Mini 2 - week 3-6 Flashcards
1
Q
Describe the regulation of F2,6BP in the cell.
A
cAMP -> PKA -> phosphorylates PFK2/FBP2 (dual enzyme) and stimulates its F2,6bisphosphatase activity which lowers F2,6BP. Glucagon or epinephrine (in skeletal muscle) stimulates this. In skeletal muscle, the PKA phosphorylation of PFK2/FBP2 is on a different side and cannot be inactivated.
2
Q
What are various organelles doing at mitosis?
A
The ER and golgi vesiculate and reform at telophase. THe mitochondria, lysosomes, and peroxisomes remain intact.
3
Q
What is the anatomical location and auscultation site of the mitral/bicuspid valve?
A
Medial left 3rd intercostal space. Auscultation site: Left midclavicular 5th intercostal space.
4
Q
What is Zellweger syndrome?
A
A peroxisomal disorder where you are homozygous for a bad copy of the PTS receptor and so have empty peroxisomes. Many die in utero/at birth. Impaired neuronal migration/positioning, brain development.
5
Q
What is fascia adherens?
A
Similar to macula adherens, anchors actin filaments, ribbon-like structure that stabilizes non-epithelial tissue.
6
Q
Which steps in glycolysis generate energy?
A
G3P -> 1,3BPG (glyceraldehyde phosphate dehydrogenase) - makes an NADH 1,3 BPG -> 3PG (phosphoglycerate kinase) and PEP -> pyruvate (pyruvate kinase) generate an ATP. All these steps happen twice for one glucose.
7
Q
What is pes planus?
A
Flat foot / fallen arches.
8
Q
Where does the biceps femoris insert?
A
The head of the fibula.
9
Q
What is the IC concentration of sodium?
A
15mM
10
Q
What does the great cardiac vein run with?
A
The anterior interventricular artery/LAD.
11
Q
What is the M-Cdk complex?
A
Cdk1-B
12
Q
Describe skeletal muscle cross-bridge cycling.
A
Ca++-troponin (made of C, I, one other subunit) move tropomyosin on the actin, exposing the myosin binding sites.
13
Q
When does heart development begin? describe it up until the formation of the primitive heart tube.
A
Week 3. Splanchnic mesoderm craniolateral to the above neural plate proliferates into a right and left tube. Apoptosis fuses the tubes (except at cranial and caudal ends) and forms an inner endocardial layer. middle cardiac jelly layer, and outer myocardial layer.
14
Q
What’s a mixed nerve?
A
Contains both afferent and efferent fibers.
15
Q
Describe the left ventricle.
A
Rough segment (trabeculae carnae), smooth segment (aortic vestibule), mitral/bicuspid valve (chordae tendinae, anterior and posterior papillary valves), a thicker wall.
16
Q
What forms the epicardium?
A
Mesodermal cells that migrate from the developing liver.
17
Q
What ganglia do CN III parasympathetic fibers synapse at?
A
Ciliary ganglion
18
Q
How can lipids move in the cell?
A
1) lateral diffusion (SER/RER) 2) Translocate between leaflets 3) Vesicular transport 4) Movement through cytosol by attaching to lipid-transfer proteins (non-specific, pick up at lipid-rich areas, drop off at lipid-poor areas)
19
Q
What is the effect of insulin?
A
Liver and muscle: upregulates glycolysis, glycogenesis, fat and protein synthesis, in muscle it also upregulates the GLUT4 transporter. Adipose: Upregulates glycolysis, upregulates adipocyte lipoprotein lipase which increases uptake of fatty acide from chylomicrons and VLDLs. Insulin dephosphorylates.
20
Q
Describe Klinefelter’s Syndrome.
A
XXY. Developmental delay/learning disability/social maladjustment. Long limbs, tall, small testes. Reduced testosterone/sexual function. 55% have gynecomastia - risk of breast cancer. 15% are mosaics (ND in mitosis). Complications can be obesity, diabetes, pulmonary disease, problem with thyroid function. Androgens can virilize but may worsen gynecomastia.
21
Q
How are nuclear lamins dealt with in mitosis?
A
They are phosphorylated and break down, then they are dephorphorylated at telophase. The assembling lamina binds condensing chromatin to the nuclear envelope vesicles - this drives envelope reassembly.
22
Q
What innervates the anterior arm muscles?
A
The median nerve except for flexor carpi ulnarus and the 4-5 digits of flexor digitorum profundus, which are innervated by the ulnar nerve.
23
Q
Describe ischemic cell injury.
A
Impairment of blood supply to the tissue results in lack of oxygen and loss of ATP generation by oxphos. Accumulated pyruvate converts to lactate, and the result is osmotic stress, activation of lysosomal enzymes, tissue acidification.
24
Q
What is talipes equinovorus?
A
“clubfoot” - a congenital defect more common in boys, treated by braces/casts of surgery.
25
What is the rate limiting enzyme in cholesterol synthesis?
HMG-CoA reductase
26
What are the nerve roots of the sciatic nerve?
L4-S3.
27
What comprises the central nervous system?
Cortex, cerebellum, spinal cord. Virtually no connective tissue.
28
What do peroxisomes synthesize?
Plasmalogens (a major phospholipid class found in myelin) - H2O2 used in steps. Also participate in synthesis of bile acids from cholesterol. Bile acids needed to digest/absorb fats and fat soluble vitamins.
29
What establishes the embryo axes?
The primitive streak - cells condense in the posterior embryo up to about halfway. Determines situs solitus vs situs inversus.
30
Describe the aortic arch.
Begins and ends at level of sternal angle, arches over the left hilum superiorly and posterolaterally to the left, then descends inferiorly beside T4-T12 vertebrae (thoracic aorta). Branches are brachiocephalic trunk, left common carotid artery, left subclavian artery. Variations - can have retroesophageal right subclavian artery (no brachiocephalic trunk), esophagus compressed. Can also have double arch of the aorta/vascular ring anomaly. Can cause stridor and dysphagia.
31
In what conditions does the trachea deviate to the affected side?
Open pneumothorax, lung agenesis, pneumectomy
32
What is the IC concentration of calcium?
10^-7 - 10^-5 mM
33
What is thought to be the cause of sirenomelia?
The loss of mesoderm un the lumbar/sacral region.
34
What is the name of the anastomosis of arteries around the knee joint?
The genicular anastomosis (genicular branches of popliteal artery)
35
What makes up the cutaneous innervation to the buttocks?
The superior/middle/inferior cluneal nerves.
36
What are the superior mediastinal structures?
Arch of Azygous Phrenic nerve Vagus nerve Thoracic Duct Left recurrent laryngeal nerve Brachiocephalic veins (and SVC) Aortic Arch (and its 3 branches) Thymus Trachea Lymph nodes Esophagus (A PVT Left BATTLE)
37
Where is the apex of the heart?
Inferolateral part of LV, lies along midclavicular line at the left 5th intercostal level.
38
Describe elastic fibers.
Made of elastin core with fibrillin surrounding it. Made by fibroblasts and smooth muscle cells in arteries, also exists in many tissues. Marfan syndrome is a mutation in these fibers - cardiovascular symptoms life threatening.
39
What is the insertion of the obturator internus and the superior and inferior gemellus?
The trochanteric fossa.
40
Where do you find pseudostratified columnar epithelium?
In the trachea (respiratory epithelium, ciliated, has goblet cells). In the epididymis (stereocilia).
41
Describe unipolar (or pseudounipolar) neurons.
Single process that bifurcates close to the cell body, longer branch extends to the peripheral ending, other to the CNS. Spinal ganglia and most cranial ganglia are like this.
42
What are the nerve roots of the tibial nerve?
L4-S3.
43
What is tennis elbow and golfer's elbow?
Tennis - lateral epicondylitis Golfer - medial epicondylitis
44
How can glands be classified?
Exocrine (retains connecting stalk) or endocrine. Simple or compound, tubular or acinar. Serous (purple/blue, secretes watery fluid usually with proteins) or mucous.
45
Where does the rectus femoris originate?
Anterior inferior ilia spine, and ilium superior to the acetabulum.
46
What kind of proteins are translated on ER ribosomes?
Secreted ones, membrane proteins, lysosomal/ER/golgi lumen proteins.
47
Describe the metaphase-to-anaphase checkpoint.
It checks that the chromosomes are complete, spindles attached. APC combines with cdc20, which activates it. (M-Cdk also helps activate it). Securin prevents separase from acting to cleave cohesins, but APC degrades securin via ubiquitination (at point of cell division it will also degrade Cyclin B)
48
What functions does stratified squamous epithelium have?
It protects the underlying tissues in areas subjected to abrasion.
49
Where do most ectopic pregnancies occur? In what kinds of women are they most commonly? To what level do these pregnancies develop? What is the triad?
In the ampullary region. Most common in women with prior surgery, endometriosis, PID (scarring can halt it). Most develop to 8-10 weeks. The triad of rupture/prerupture is amenorrhea, acute pain, vaginal bleeding.
50
What does the ilifemoral ligament do?
Limit hyperextension.
51
What is special about the tibialis anterior?
It is the most superficial muscle of the anterior compartment, and it also does foot inversion.
52
Describe the internal intercostal/oblique muscles.
Anterior and then a membrane. Go from sternum to angle of ribs. The neurovascular bundle is deep to them.
53
What does the SVC drain?
All structures superior to the diaphragm except the heart.
54
What are the three periods of embryonic development?
Week 1-2: germinal, 3-8: embryonic, 9 onwards: fetal
55
What is special about the plantaris?
It is not found in all people.
56
Describe the mechanism in E1 of PDH. Include cofactors.
Pyruvate reacts with TPP (thiamine pyrophosphate/B1) to form hydroxy-ethyl-TPP. A deficit of B1 results in Beri-beri, GI issues, and neurological findings.
57
What provides cutaneous innervation to the medial leg and bit of the foot?
The saphenous nerve (a branch of the femoral nerve).
58
What does inferior gluteal nerve injury result in?
Weakness of hip/thigh extension and lateral rotation. Weakness rising from a siting position and/or climbing stairs.
59
What is CoA-SH?
A combination of ADP, cysteamine. and panthenoic acid (B5). It acts as a carrier for high energy acyl bonds.
60
What is the Nernst Equation?
Vm = -61/z X log[i]/[o] Assumes T=37C
61
What are the nerve roots of the common fibular nerve? How does it travel?
L4-S2. It moves posteriorly to anteriorly by winding around the head and neck of the fibula - it is very superficial.
62
What is a pulmonary embolism?
Obstruction of the pulmonary artery by an embolus (usually from lower limb). Associated with acute respiratory distress, cor pulmonade (dilated RV), and pulmonary infarct. Symptoms are dyspnea, sharp chest pain, blood-tinged foamy sputum.
63
What is the normal reaction to the patellar reflex? What does it test?
The patellar nerve - should extend knee.
64
What's the structure of skeletal muscle? What are the different units?
Myofibrils are the contractile elements - made of repeating sarcomere units. They are a bundle of myofilaments - actin + myosin. A muscle is made of fascicles, which are made of fiber/cells.
65
What is NRF2?
A transcription factor. It stimulates antioxidant genes by binding ARE in promoters and enhancers. In the absence of oxidative stress, it is kept in the cytosol and sent to the proteasome by KEAP1 but oxidants release KEAP1 from NRF2. The genes it regulates are for glutathione metabolism, NADPH production, genes for proteostasis proteins, genes for phase II drug metabolism.
66
Can the visceral pleura feel pain?
No
67
What kind of neurons are sensory./dorsal root ganglia?
Always pseudounipolar.
68
When does the amnion form?
By day 8. It's made from amnioblasts, and will eventually surround the entire membrane.
69
Describe mtDNA.
Circular, double stranded, no histones/nucleosomes. 2-10 copies of genome per mitochondria. 37 genes (13 proteins, 2 rRNAs, 22 tRNAs). New mitochondria arise from the division of old mitochondria. Most mitoch proteins, however, are nuclear-encoded and post translationally transported with a mitochondrial targeting sequence. Sperm mitochondria are tagged in the testes with ubiquitin.
70
Describe the terminal sac period of lung maturation.
24 weeks - birth. The primitive alveoli develop, the epithelium thins and capillaries come in contact with it. The epithelium differentiates into type I pneumocytes (flat, sites of gaseous exchange) and type II pneumocytes (produce surfactant that decreases surface tension).
71
What is the name of the arterial arch on the plantar surface of the foot? What's it made of?
The deep plantar arch. The lateral and medial plantar artery, both of which come from the posterior tibial artery. It anastomoses with the arcuate arch.
72
Describe the placenta septa.
By month 4-5, the decidua basalis is eroded to enlarge the intervillous space. Placenta septa are wedge shaped areas of decidua that project to the chorionic place - they separate the placenta into cotyledons.
73
What kind is joint is the hip joint? What are other names for it?
Aka the coxal/acetabular joint. It is a multi-axial, ball-and-socket type joint. Blood supply to this joint is the same as blood supply to the surrounfing skin and muscles.
74
What is the EC concentration of sodium?
150mM
75
Describe mast cells.
Wandering CT cells. Large basophilic membrane-bound granules containing histamine and heparin. Frequently found around blood vessels, has IgE receptors - at Ag exposure, binds, cross-links, activates adenylate cyclase -\> entry of calcium triggers rapid granule exocytosis. It also releases prostaglandins and leukotrienes and they are also affected by eosinophil and neutrophil chemotactic factor (ECF and NCF).
76
What is the BcL2 family?
A family of enzymes that form pro and antiapoptotic heterodimers. BcLx is pro-apoptotic.
77
What is Familial Hypercholesteremia?
Almost always a defective LDL receptor or ApoB protein. Results in high serum cholesterol, might see yellow deposits of cholesterol-rich fat around the body. Heterozygotes (1/500) may develop cardiovascular disease prematurely (30-40) whereas homozygotes may have severe cardiovascular disease in childhood.
78
What direction does the patella most commonly dislocate?
Laterally.
79
Where do you auscultate the apex of the lung?
Superior to the medial 1/3 of the clavicle
80
What is PROM?
Premature rupture of the membrane (before contractions). Occurs in 10% of pregnancies.
81
What is the EC concentration of potassium?
5mM
82
How can damaged DNA affect the G1 checkpoint?
It activates ATM/ATR kinase which activates Chk1 and Chk2 which phosphorylate and activate p53, which regulates p51 (a Cdk inhibitor protein)
83
Describe the venous drainage of the heart.
Small, middle, great cardiac veins drain into the coronary sinus and tributaries. Tiny anterior cardiac veins drain into right atrium. There are also thebesian veins.
84
What is the Haber-Weiss reaction?
H2O2 + superoxide -\> hydroxylradical + OH- + O2
85
What is myasthenia gravis?
Autoimmune disease destroying Ach receptors at the NMJ. Weakness, rapid fatigue of any skeletal muscles.
86
What makes up ground substance?
Glycosaminoglycans proteoglycans, multiadhesive glycoproteins.
87
Describe a double SVC.
The left anterior cardinal vein persists, the left brachiocephalic vein fails to develop. The coronary sinus is dilated.
88
What qualifies someone as being hypoxic?
A pulse ox under 95%.
89
What is the dorsal venous arch made of?
The small and great saphenous veins.
90
Describe peroxisome structure.
Small, membrane-enclosed, have \>30 enzymes (peroxins). Spherical, smaller than mitochondria. Eukaryotes all have multiple cells with us, but not all cells have them. They are numerous in liver and kidney cells. Amount also varies based on need. They cannot be seen unless specifically stained for. Some species (but not humans) have electron dense inclusions in their peroxisomes seen on EM.
91
What are the 5 dilatations of the primitive heart tube, cranial to caudal?
Truncus ateriosis, bulbus cordis, ventricle, atrium, sinus venosus. Blood flow is caudal to cranial.
92
Where do the bronchial arteries arise from?
Right - thoracic aorta or 3rd posterior intercostal artery Left - thoracid aorta
93
What are Bouchard's and Heberden's nodes?
Bouchard's is a bony bump at the PIPs and Heberden's is one at the DIPs.
94
What is the meniscus of the knee?
A crescent shaped fibrocartilage pad that deepens the articular surface between the tibia and femur and provides shock absorption. There is a medial part firmly attached to the tibial collateral ligament and a lateral part not attached to the fibular one. The popliteus tendon also passes between the two menisci.
95
What degrades proteins?
The lysosome and proteasome.
96
What are the regulators of glucokinase?
High F6P promotes nuclear localization and binding to GKRP (glucokinase regulatory protein), wherease glucose promotes release and return to cytoplasm, therefore upregulating activity.
97
What are the 5 types of atrial septum defects? Are they cyanotic?
Acyanotic. Probe patent foramen ovale (25% of people, linked to migrains), Ostium secundum defect (incomplete fossa ovalis due to many possible reasons), Endocardial Cushion defect with ostium primum defect (often with mitral valve defects), Sinus venosus defect (close to SVC, high, often have pulmonary vein problem - might attach to RA and not LA) Common atrium/Cor Tricolae biventriculare (often associated with heterotaxy syndrome).
98
How does oligomycin work?
It blocks the ATPase in the ETC so the gradient gets very strong - too strong for the flow.
99
What's special about phosphotidylserine?
It is the only negatively charged phospholipid, and it always is in the leaflet that faces the cytoplasm.
100
Where does the iliopsoas insert?
Lessert trochanter of femur.
101
What does through the adductor hiatus?
The femoral artery and vein move through it from anterior thigh to posterior knee (popliteal fossa), and change their names to the popliteal artery and vein.
102
What functions does simple cuboidal epithelium have?
Protection, secretion, absorption.
103
How do you image chromosomes?
1) obtain from metaphase cell (usually WBC) 2) Add phytohaemagluttinin (PHA) - culture for 3 days in incubator 3) Colchicine/colcemid inhibits spindle formation/stops division 4) Hypotonic saline + fixative (alcohol) to avoid enzyme breakdown of chromosomes - let drop fall, cell bursts 5) Digest with trypsin (protease) if banded karyotype is the aim 6) Stain with Giemsin
104
What is gliosis?
A nonspecific reactive change of the glia in response to CNS damage, proliferate to form scar tissue. Mostly this is astrocytes but sometimes also microglia and oligodendrocytes. They are a feature in MS, stroke. To see astrocytes in this, use GFAP stain - GFAP (glial fibrillary acidic protein) is an astrocyte intermediate filament.
105
Describe the left coronary artery.
Gives off Anterior IV Artery/LAD (supplies RV, LV, anterior 2/3 of IV septum, apex, anastomoses with post. IV branch of RCA at apex, gives off diagonal branch). Gives off Circumflex artery (supplies LA, LV, anastomoses with RCA at coronary sulcus), which gives off Left Marginal artery (supplies LV, anastomoses at IV branches).
106
What is the difference between the main primary bronchi?
Right is more vertical and has a larger lumen.
107
Describe the second week of embryo development.
The uteroplacental circulation is established. The epiblast forms the extraembryonic mesodermal layer (cavities formed). The hypoblast divides, exocoelomic cysts form. Extraembryonic cavity now called chorionic cavity. Extraembryonic mesoderm called chorionic plate. The cytotrophoblast cells, surrounded by syncytia, proliferate and develop primary villi.
108
What happens if you have an absence of the hepatic segment of the IVC?
Usually associated with heart malformations. The blood from the caudal parts just drains into the azygos and hemiazygos veins and enters via the SVC.
109
What is special about the obturator extremis?
It laterally rotates the thigh - the other medial thigh muscles medially rotate/adduct the thigh.
110
What is a contiguous gene disorder?
A deletion/duplication in part of a chromosome - is inherited like a gene disorder but it is not a single gene issue.
111
What does the sinus horn of the embryo become?
By week 4/5 there is left to right shunting of blood - the right sinus horn grows and pushes it self into the right atrium. The remnant of the left sinus horn forms the oblique vein of the left atrium and the coronary sinus.
112
How does the TCA cycle contribute to gluconeogenesis?
It feeds pyruvate and amino acids towards it by increasing oxaloacetate concentration.
113
What provides cutaneous innervation between the first and second toes dorsally?
The deep fibular nerve.
114
What is synapsis?
The process of homologous chromosomes associating for recombination/
115
What ganglia do CN VII parasympathetic fibers synapse at?
Pterygopalatine and submandibular ganglion
116
What is the adductor canal?
A fascial compartment posterior to sartorius thorugh which travel the femoral artery/vein, nerve to vastus medialis, saphenous nerve.
117
What do the subcardinal veins form?
Portion of IVC, renal veins, gonadal veins.
118
What are the types of glucose transporters?
GLUT1 (basal uptake) GLUT2 (liver - highest Km) GLUT3 (brain) GLUT4 (muscle and fat tissue, insulin responsive)
119
How are citrate synthase, isocitrate dehydrogenase, and alpha-KG dehydrogenase regulated?
By product inhibition, energy state/need, and NAD+ supply. alpha-KG dehydrogenase is regulated exactly like PDH, theyre very similar.
120
Where do the posterior intercostal arteries originate from?
1-2nd from the subclavian - costocervical trunk. 3-11th from the thoracic/descending aorta.
121
What is the action of the lumbricals? What innervates them?
Flex the metacarpophalangeal joints, extend the interphalangeal joints of digits 2-5. 1+2 - the median nerve (medial and lateral branches) 3+4 - the deep branch of the ulnar nerve
122
What is the action of the lateral leg muscles? What is the blood supply/innervation?
Eversion and weak plantarflexion. The perforating branches of the fibial and posterior tibial arteries and veins. The superficial fiibular nerve.
123
What are the free radicals, in increasing order of harmfulness?
H2O2 (hydrogen peroxide), O2- (superoxide), OH (hydroxyl radical).
124
What organelles are localized to the perikaryon/soma?
Most of the ER (but SER can extend sometimes) and all of the golgi.
125
What is the crista terminalis called externally?
The sulcus terminalis.
126
What conditions is oxidative stress linked to? ROSs?
Aging, neurodegenerative disorders, atherosclerosis through LDL oxidation. ROS is required for normal muscle function but high amounts are associated with muscle fatigue.
127
What is the action and origin of the gastrocnemius?
Plantarflexion when knee is extended, flexes leg at knee. Origin: the lateral and medial condyles of the femur.
128
Describe postductal coarctation/stenosis of the aorta.
Most common distal to the left subclavian artery. Results in dilated torturous arteries, rib notching on the 3-9th rib inferior margins, lowered blood pressure in lower limb and higher in upper limb. Collateral circulation: aortic arch -\> subclavian -\> internal thoracic -\> anterior intercostal -\> posterior intercostals -\> thoracic aorta. Coarctation can be pre or postductal and with or without patent ductus arteriosus.
129
How is pyruvate converted to oxaloacetate?
Through pyruvate carboxylase. Requires the hydrolysis of ATP, and needs biotin (B7) as a cofactor.
130
What innervates adductor pollicis?
The deep branch of the ulnar nerve.
131
Describe cardiac muscle.
Only in the heart, striated uninuclear, less organized actin/myosin arrangement. Lots of mitochondria, fatty acids, lipofuscin granules often found in long-lived cells. Have intercalate discs (gap junctions, desmosomes/macula adherens, fascia adherens). We are born with a set number of cardiomyocytes, less than half of which get turned over in a lifetime.
132
Can cardiac muscle regenerate?
Barely. Defects are replaced by CT growth and proliferating fibroblasts.
133
Describe heart conduction.
SA node is the pacemaker -\> AV node (through AV bundle and right and left bundle branches) -\> papillary muscles/ventricular walls on each side of IVS.
134
What are myoepithelial cells?
Contractile non-muscle cells. Keratin IFs, similar contraction to smooth muscle.Possess desmin. Exist in certain glands and share basal laminae of secretory and duct cells, express secretory material from glandular epithelium out of gland into ducts. In lacrimal glands in response to Ach and in mammary glands in response to oxytocin.
135
What comprises a peripheral nerve?
axon + Schwann cells + CT + blood vessels
136
What's more lateral, the extensor carpi radialis longus or brevis?
Longus is more lateral.
137
What is HSP70?
A chaperone protein that assists in folding. It is ATP-binding, recognizes a series of hydrophobic amino acids, binds, waits for a 'clock' to hydrolyze ATP - this gives time for the rest of the protein to be made.
138
What provides cutaneous innervation to the dorsum of the foot (except for the skin between the first and second toes)?
The superficial fibular nerve.
139
What is the action of catalase?
It converts hydrogen peroxide into two waters.
140
Which steps in glycolysis require ATP?
Glucose -\> G6P (glucokinase/hexokinase), and F6P into F1,6BP (PFK1)
141
Where do you do a pericardiocentesis?
Left 5-6th intercostal space near the sternum at an infrasternal angle.
142
What do growth factors do?
They stimulate the PI3K pathway which stimulates TOR and upregulates all translation.
143
Describe synapses.
Mostly chemical but can be electrical via gap junctions - often where the fastest response in needed e.g. defensive reflexes. Mostly axodendritic but can be other.
144
What is the general action of the anterior thigh?
Extension at the knee, flexion at the thigh.
145
What are cervical ribs?
0.5-2% of the population, can be uni or bilateral. They are associated in thoracic outlet syndrome - compression of neurovascular structures exiting/entering the superior thoracic aperture.
146
What do the 4th aortic arch arteries become?
Left becomes arch of aorta (also formed from partitioning of outflow tract), Right becomes proximal right subclavian (distal right subclavian comes from 7th intersegmental artery).
147
Describe ventricle formation, including the septum.
Rough part from primitive ventricle, smooth part from bulbus cordis. The muscular IVS forms in end of week 4 from myocardium but halts in week 7 and does not fuse with the endocardial cushion (IV foramen). The membranous IVS is an extension of tissue from the right side of the endocardial cushion as well as tissue from the aorticopulmonary septum (neural crest cells), as outflow tract is being partitioned.
148
Which cells are professional phagocytes?
Neutrophils and macrophages.
149
Where is the base of the heart?
Mainly the LA, some RA. T5-T8 level, overlays esophagus and thoracic aorta. Receives pulmonary veins on LA part, SVC/IVC on RA part.
150
How do the common iliac arteries form embryologically?
They form from the 5th intersegmental arteries 5ISA. These also give rise to the external iliac and proximal iliac arteries.
151
What do the 6th aortic arch arteries become?
Right forms right pulmonary artery, Left forms ductus arteriosus (begins ligamentum arteriosum after birth) and some of left pulmonary artery.
152
What is hemoptysis?
Spitting blood. If it's from the lungs, 95% its from the bronchial vessels.
153
What is the action of the piriformis?
It laterally rotates an extended thigh, abducts a flexed thigh. It exits through the greater sciatic foramen and so do the superior and inferior gluteal artery.
154
What kind of gland is the pancreas?
Both endo and exocrine.
155
How many ATPs are made from TCA? DIrectly and indirectly.
20 (2GTP, 6NADH, 2FADH2)
156
What innervates the popliteus? What is its action?
The tibial nerve. Weak knee flexion / unlocks knee joint by rotating femur 5 degrees laterally on fixed tibia (or tibia 5 degrees medially on fixed femur).
157
Describe GAGs.
Long straight repeating disaccharide units, mostly sulfated/carbonyls (negative charge). They attract cations which attract water, which hydrates the gel and makes it able to resist compressive force.
158
What screening test values go up, down, and stay the same with increased disease prevalence?
Up: accuracy, PPV Down: NPV LR+ and LR- stay the same.
159
What's the A-band of a sarcomere?
The overlap of myosin and actin.
160
What ganglia do CN X parasympathetic fibers synapse at?
Ganglia near the innergated organ. Vagus nerve is the "wanderer" - travels as far as the left colic flexure.
161
What is the general blood supply and innervation of the anterior thigh?
Femoreal artery/vein/nerve (L2, L3, L4)
162
Describe the paths of the phrenic nerves.
Anterior to the lung roots. Right descends along right side of SVC/IVC and pierces diaphragm near caval opening. Left descends lateral to left subclavian artery, course superficial to left atrium and ventricle, pierces diaphragm to left of pericardium.
163
What do the 2nd aortic arch arteries become?
Dorsal end forms hyoid arteries from which arise stapedial arteries. These connect the branches of the future internal and external carotid arteries.
164
What is multiple sclerosis?
A CNS autoimmune demyelinating disease.
165
What is cohesin?
It is an enzyme that holds sister chromtids together.
166
What are muscle spindles?
CT capsule surrounding a fluid-filled space that has a few thin, non striated fibers dense with nuclei called intrafusal fibers. Several sensory axons wrap around these fibers. The change in length of the surrounding striated extrafusal fibers are detected by the muscle spindles and the information is relayed to the spinal cord.
167
What proteins are involved in vesicle budding?
Clathrin (RME), COPI, COPII induce curve in the membrane, dynamin cuts the stalk.
168
Where do the rough and smooth parts of the left atrium develop from embryologically?
A single pulmonary vein grows out of the primitive atrium (eventually splits into 4), the rough part are the cells that outgrew to do this, the smooth is the cells that outgrew but returned.
169
What is a nerve fiber vs a nerve?
A nerve fiber is an axon or dendrite, a nerve is a collection of fibers (mostly axons and mostly myelinated).
170
What is the general autonomic visceral motor pathway?
2 neuron pathway. Preganglionic neuron cell body in lateral horn, postganglionic varies. Generally the preganglionic axon is myelinated and the postganglionic is unmyelinated.
171
Name all the monosomies compatible with life.
Just X. \>99% die in utero.
172
What is a P value?
The probability a test statistic could have occurred by chance. It needs to be less than alpha to conclude statistical significance. The smaller a P value, the greater difference between groups, smaller probability of making a type I error, greater the significance of the finding.
173
Describe pulmonary circulation.
Pulmonary arteries turn into lobar arteries which turn into tertiary segmental arteries (and segmental branches) which supply a single bronchopulmonary segment. 2 pulmonary veins drain into a single lung, run independent of arteries and bronchi. They are intersegmental.
174
Where does shingles lie dormant?
In the dorsal root ganglion.
175
What are the hypothenar muscles and what innervates them?
Abductor digiti minimi Opponens digiti minimi Flexor digiti minimi brevis The deep branch of the ulnar nerve.
176
What are myoepithelial cells?
Cells between gland cells and their basal lamina. When innervated, they cause secretion out of the gland. They are 'true' epithelial cells, with keratin intermediate filaments. They are found in sweat, lacrimal, salivary, and mammary glands.
177
What happens if you damage the median nerve at the wrist?
Thenar damage, loss of thumb opposition, weakened abduction and flexion, "Ape hand".
178
What are PNS satellite cells?
The primary glia - cover the surface of the soma in sensory and autonomic ganglia. Thought to play a similar role to astrocytes, supply nutrients, some protective/structural functions.
179
What functions does transitional epithelium have?
Expansion to hold increased volume and protect against hte hypertonic and cytotoxic effect of urine.
180
What is variable expressivity?
Where there is a difference in severity or age of onset for the same genotype. Usually in dominant illnesses, there's no no symptoms just variation.
181
What is patent ductus arteriosus?
A connection between the aortic arch and the pulmonary trunk. It can close spontaneously by day 3 in 60% of normal term neonates - give preemies NSAIDs - block E1 prostaglandins that keep it open. Can be ligated with relatively low risk.
182
What do the sympathetic fiber axons from T1-T4 do?
Innervate the heart and lungs. (Cardiopulmonary splanchnic nerves).
183
Describe the venous system of the embryo.
3 paired veins - Umbilical (right and left, drain poorly oxygenated blood from the yolk sac), Vitelline (right and left, return oxygenated blood from the placenta), Cardinal (anterior, posterior, subcardinal, supracardinal, drain poorly oxygenated blood from the embryo).
184
What is a primary lysosome?
A "virgin" lysosome, it buds off from the golgi before receiving any material to be digested.
185
What causes hay fever?
Histamines by nasal mucosa mast cells.
186
What are the four types of junctional complexes in the lateral domain of epithelia?
Zonula occludens/tight junctions, zonula adherens, macula adherens/desmosomes/spot adhesion, gap junctions.
187
How does CO work in regards to the ETC?
It binds heme on complex IV of the ETC but the initial symptons are not because of that, they're because of the loss in O2 carrying capacity.
188
What makes up the lumbar nerve plexus?
The ventral rami of L1-L4.
189
What is the threshold for action potentials?
About 15mV higher than the resting membrane potential?
190
Desribe reticular lamina.
It is secreted by CT fibroblasts, and attached to the basal lamina below it, with collagen VII (anchoring fibrils) and III (reticular fibrils).
Basal lamina and reticular lamina make up the basement membrane, which can be seem in LM.
191
What is Dupuytren's Contracture?
The palmar fascia of the medial hand thickens, pulling the fourth digit in flexed.
192
What is the general action of the posterior leg muscles? What are their blood supply/innervation?
Plantarflexion. The posterior tibial, fibular, popliteal arteries/veins. The tibial nerve (L4-S3).
193
What do the sympathetic fiber axons from T12 do?
Form the least splanchnic nerve -\> innervates inferior mesenteric ganglia.
194
Describe epineurium.
Dense irregular CT (fascia), mainly type I collagen, continues down to fill spaces between bundles, surrounds entire nerves.
195
Describe dark G-bands.
Later replication, fewer transcriptionally active genes, probably shorter loop structures, more condensed chromatin structure, higher in A-T base pairs, stain dark with quinacrine (q-bands) and are light with R-banding.
196
What is the Fenton reaction?
A way that iron catalizes hydroxyl radical formation H2O2 + Fe2+ -\> OHradical + OH- + Fe3+ Fun fact: iron can also be reduced by superoxide
197
Describe the general mechanism of fatty acid synthesis.
Occurs in liver when there is sufficient carb influx to raise acetyl CoA concentrations beyond local energy needs. AcCoA converted into FAs which are then added to glycerol phosphate and become VLDLs. This process gets its ATP from oxphos, and its NADPH from HMP/PPP (which can also make ribose via ribose-5-phosphate).
198
How does the foregut opening form?
The oropharyngeal membrane (endoderm+ectoderm) ruptures in week 4 to form it.
199
What are A type chromosomes?
Large, mear metacentric. 1-3.
200
What are uncouplers? Name some.
Small, hydrophobic acids that can just diffuse in. THey bring H+s with them into the mitochondrial matrix, thereby reducing the gradient and turning off ATP synthesis. 2,4 dinitrophenol, FCCP, CCCP, acetylsalicylate (aspirin) at high concentrations, UCP1/thermogenin in brown fat of hibernating animals.
201
How can you make more peroxisomes?
By fission or de novo (upregulate translation of PTS receptor, upregulate translation of peroxins all with PTS)
202
What muscles are affected by ulnar nerve damage at the elbow?
The medial 1/2 of the flexor digitorum profundus. Cannot flex the DIPs of 4-5. Claw becomes less prominent "ulnar paradox".
203
What happens once the sperm enters?
The sperm and egg PM break down and bind at the fusion area. The sperm cell membrane enters the oocyte cytoplasm and its mitochondria and tail degenerate. The sperm nucleus forms the male pronucleus, the secondary oocyte finishes meiosis II, and the two pronucleii fuse into a zygote.
204
What are the inheritances of different loss of function mutations?
Compensation or 1/2 the product is enough - recessive inheritance. 1/2 the amount of product is not enough (haploinsufficiency) is dominant inheritance.
205
What is reduced penetrance inheritance?
When someone has the genotype but doesn't show symptoms (usually in dominant inheritance).
206
What makes up the femoral triangle?
The inguinal ligament, the sartorius, and the adductor longus.
207
What does it mean that the EC and IC are electroneutral?
They each have the same number of positive and negative ions?
208
What is allelic heterogeneity?
Different alleles at the same locus/gene. Symptoms may be the same or different.
209
Where do you find stratified squamous epithelium?
linings of the esophagus, mouth, vagina, urethra, anus. Keratinized is only found in the epithelium.
210
Describe leg lymph drainage.
It follows the route of the great saphenous vein then goes to the superficial inguinal LNs, then the deep inguinal, external iliac, and lumbar/aortal.
211
What is stage 1 hypertension?
For someone 18-60/diabetic/renal disease: systolic 140-149, diastoic 90-99 For someone over 60: 150-159 systolic
212
What is Patellofemoral pain syndrome?
"Runner's Knee". It is pain/inflammation deep to the patella due to abnormal gliding over the femur surface. Causes: excessive downhill running, direct trauma to patella, weak vastus medialis, osteoarthritis.
213
What is the anatomical location and auscultation site of the tricuspid valve?
Medial aspect of right 5th costal cartilage. Auscultation site: Left parasternal 5th intercostal space
214
What are shin splints?
Small tears in the periosteum (dense layer of vascular CT) at the attachment of the anterior compartment muscles - commonly tibialis anterior. Treat with rest.
215
What innervates the mediastinal pleura?
The phrenic nerve (anterior rami C3-C5). It also innervates the pericardium (pain referred to root of the shoulder) and central diaphragm.
216
What is "trigger finger"?
Flexor tendinitis - the tendom becomes inflames and swells too much to pass back into the sheath, locking the finger in a flexed position. Common in diabetics and people with rheumatoid arthritis.
217
How does the BCV develop?
Develops from the anastomoses of the left and right anterior cardinal veins when the caudal left anterior cardinal vein degenerates.
218
When does the embryo embedded fully in the endometrium?
Day 9-10. The defect is closed by a fibrin coagulum plug.
219
What do the 3rd aortic arch arteries become?
The common carotid arteries - the internal also comes from the dorsal aortae.
220
What do the umbilical veins form?
Ligamentum teres. They degenerate early in fetal life.
221
What is inside the femoral triangle?
The femoral nerve, artery, vein, an empty space, and the lacunar ligament. NAVEL
222
What are Nissl bodies?
Neuron specific RER + free ribosome aggregations due to the neuron's high synthetic activity. They stain basophilic.
223
How is the transverse pericardial sinus formed?
The dorsal mesoderm differentiates and provides structural support to the posterior body wall. When the heart gets stronger, it degenerates and leaves behind the transverse pericardial sinus.
224
What does rib 2 have that typical ribs do not?
A serratus anterior tuberosity.
225
What are the ligaments of the knee?
Patellar (continuation of quadriceps femoris tendon to the tibial tuberosity). Tibial and Fibular collateral. Anterior and posterior cruciate.
226
Describe notochord formation.
It forms as the endoderm cells differentiate and push into the mesoderm and fuse, detaching from the underlying endoderm. Failure can lead to a spontaneous abortion. It degenerates as vertebrae form, the remnants remain as nuclei pulposi.
227
Which anterior arm muscles originate at the medial epicondyle?
Pronator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis Flexor carpi ulnaris
228
What are the three layers of the maternal part of the placenta and where does it differentiate from?
The endometrium. The decidua is the functional layer that separates from the uterus in childbirth. Decidua basalis Decidua capsularis (overlying, superficial part of decidua) Decidua parietalis
229
What is a screening test for?
To identify a subset of people likely to have the disease - and to therefore increase efficientc of the diagnosis. Early detection, diagnosis, treatment.
230
What are the medial and lateral and inferior borders of the popliteal fossa?
Lateral - biceps femoris Medial - semimembranosus/semitendinosus Inferior - Heads of the gastrocnemius
231
Which step in the TCA cycle creates FADH2?
Succinate -\> Fumarate via succinic dehydrogenase.
232
Where do the flexor/extensor ulnaris and radialis originate?
At the base of the 5th and 2nd metacarpals respectively.
233
What's the Z-line of a sarcomere?
Connected to the sarcolemma.
234
How can the RER exchange with the SER?
Through diffusion - they are continuous.
235
What are dendritic spines?
Projections on dendrites, each is the site of a synapse. Highly plastic, morphology depends on actin, reduces with age, poor nutritition, retardation.
236
What is sperm capacitation?
The glycoprotein coat is removed from the acrosomal region plasma membrane. Only capacitated sperm can cross the corona radiata. The zona pellucida helps in cell binding - maintains binding and induces the acrosomal reaction. The acrosomal enzymes (acrosin, esterase, neuraminidase), are released, which lets sperm penetrate.
237
What is the cytoskeleton of neurons made of?
Actin.
238
Describe microglia.
The main form of CNS active defense. They are descended from monocytes, migratory, pretty evenly distributed through white and grey matter.
239
What is the transverse sinus of the pericardium?
Passage between the ascending aorta and the pulmonary trunk. A ligature is passed through this to clamp ascending aorta and pulmonary trunk during surgery.
240
How are prostaglandins synthesized?
PKC (Galphaq) stimulates MAPKwhich activates PLA2. PLA2 releases arachidonic acid, which is converted to prostaglandins and leukotrienes.
241
What are amniotic bands?
Pieces/tears of amnion that can encircle part of the fetus and result in limb constriction, amputation, craniofacial deformities.
242
Describe the G1 checkpoint.
Needs the G1-Cdk, G1/S-Cdk, S-Cdk. They hyperphosphorylate pRb - it lets go of E2F which becomes active and affects transcription to go through the checkpoint.
243
What does the nerve to obturator internus innervate?
The obturator internus and the superior gemellus.
244
What evidence do we have that neurons express a trophic effect on the cell with which they synapse?
If an axon is severed and the neuron degenrates and cannot regenerate, the post-synaptic cell atrophies and degenerates as well.
245
Describe C fibers.
1um thick, unmyelinated, 0.5-2m/s (avg 1m/s). Skin afferent fibers from nociceptors and sympathetic postganglianic efferent fibers.
246
What does the azygous vein drain?
Back, mediastinal, viscera, thoracoabdominal wall.
247
What are gliomas?
Glial tumours. Most common is astrocytoma but can also have oligodendrocytoma and ependyoma. Neuronal tumours are rare but exist.
248
What does the pubofemoral ligament do?
Prevents hyperabduction.
249
What can plantar fasciitis lead to?
A calcaneal/heel spur.
250
What is the normal delta G of glycolysis and what is it in the cell?
-7.3 kcal/mol and -13 kcal/mol due to ATP.
251
What is endothoracic fascia?
The glue holding the parietal pleura to the thoracic wall. It is made of LCT, and above the 1st rib-C7 transverse process it is thickened to cover the lung apex (Sibson's fascia).
252
Describe partitioning of the outflow tract.
Cranial version of bulbus cordis tapers into conus cordis and merges with the truncus arteriosus. The neural crest cells migrate and incade the truncal and bulbar ridges, which twist around each other and grow in a spiral fashion to form aorticopulmonary septum. The septum divides the truncus arteriosus and conus cordis into the pulmonary tract, ventral aorta, aortic sac. The aortic sac forms right and left horns to form brachiocephalic trunk, ascending aorta, proximal aortic arch.
253
What is the purpose of the Na+/K+ pump?
K+ leaks out of the cell and Na+ leaks in. THe pump exports 3 Na+s and imports K+s to maintain the gradients. This pump takes up 2/3 of the body's energy.
254
What ganglia do CN IX parasympathetic fibers synapse at?
Otic ganglion
255
Describe transposition of great vessels.
A partitioning of outflow tract defect. Septum is straight and now spiral, 3:1 males:females, results in aorta being attached to right ventricle and pulmonary trunk to left. Most infants die in first few days, extremely cyanotic. Incompatible with life unless there's an accompanying shunt (VSD, patent foramen ovale, patent ductus arteriosus). Give baby prostaglandins to keep ductus arteriosus open. Increased risk associated with rubella, other viruses in pregnancy.
256
Describe the process of PNS neural regeneration.
2 weeks post injury - less Nissl substance (RER autophagy), nucleus moves off to one side, debris removed by macrophages. 3 weeks - Schwann cells proliferate and form Schwann Tube, end of cut axon forms sprouts, one finds Schwann tube and begins elongating through it (others degenerate). In the meanwhile, the muscle is atrophying. 3 months - if successful, axons sprout through tube and grow 3-4mm/day, reaches postsynaptic membrane and establishes contact. Can be blocked by scar tissue, if its a mixed nerves you can get sensory fibers growing to a muscle which will do nothing.
257
How does neurulation begin?
The notochord induces the ectoderm to thicken and form the neural plate. By the end of week 3, lateral edges of plate elevate - form folds/groove.
258
What is special about the sartorius?
It flexes at the knee unlike most anterior thigh muscles - it also produces the cross legged position.
259
When does the primitive streak disappear? What if it doesn't?
Around week 4, it apoptoses as gastrulation nears. If something goes wrong, a sacrococcygeal teratoma can form. This is the most common newborn tumour, mostly not malignant, 80% in females.
260
What is the action of superoxide dismutase?
It converts a superoxide to O2 and water.
261
What kind of molecule is myelin?
A lipoprotein.
262
What are F type chromosomes?
Small metacentric. 19-20.
263
What is the general action of the medial thigh?
Adduction at the hip.
264
Describe ventricular septal defects.
Acyanotic. More common in males. Membranous type (issue with muscle layer) is 70%, associated with defects in the AP septum. The muscular type is often swiss cheese. Large VSDs can cause excessive pulmonary blood flow - hypertension, cardiac failure in infanct.
265
What does the coronary sinus run with?
The circumflex artery.
266
Describe the right ventricle.
Rough segment (trabeculae carnae), smooth segment (conus arteriosus/infundibulum), tricuspid valve (chordae tendinae, anterior/posterior/septal papillary muscles), septomarginal trabeculae/moderator band (runs from base of anterior papillary muscle to IV septum, carries right branch of AV node).
267
What can inhibit the complexes needed for the G1 checkpoint?
TGFbeta (epithelial cells), DNA damage, contact inhibition, cAMP (fibroblasts, smooth muscle cells).
268
What do the 1st aortic arch arteries become?
Mostly degenerates, but in adults become maxillary arteries.
269
Describe the mechanism of HIF.
Prolyl Hydroxylase is active in the presence of oxygen, where it hydroxylates HIF and it is degraded. In the absence of oxygen, it cannot do that and HIFa goes ot the nucleus and meets HIFb, where it acts as a transcription factor and increases the transcription of a bunch of stuff.
270
What makes up the right and left borders of the heart?
Right: RA, SVC, IVC Left: LV (mainly) and left auricle
271
How do cells maintain a high NADPH:NADP+ ratio?
1) G6P dehydrogenase (HMP/PPP) 2) Malic enzyme converting malate to pyruvate 3) Mitochondrial transhydrogenase that uses the proton gradient Erythrocytes depend on G6P dehydrogenase - if deficiency, can result in hemolytic anemia during oxidative stress. Lots of people have a partial deficiency - Fava beans and certain drugs can trigger this happening.
272
What are the other names for complexes I-V?
I: NADH dehydrogenase II: Succinate dehydrogenase III: Cytochrome reductase / Cyt bc1 IV: Cytochrome oxidase V: ATP synthase
273
What exits through the lesser sciatic foramen?
The tendon of the obturator internus.
274
How do ribs 10-12 differ from typical ribs?
One facet on the head. 11 and 12 have no transverse tubercle.
275
What is involved in vesicle targeting and fusion?
V-SNARE on vesicles, T-SNAREs on target membranes. a RABS (GTP binding protein) on the vesicle is localized specific tethering proteins on the membrane - the tether binds RAB, bends, and lets SNAREs bind. They have until the 'clock' of RABS hydrolyzing their GTP runs out.
276
Describe the calcaneal tendon reflex. What if it ruptures?
Normal response plantarflexion - tests S1/S2 roots of tibial nerve. Rupture - cannot rise to tiptoes, bulge in posterior leg, palpable gap where it ruptured.
277
Where do you find stratified columnar epithelium?
It's rare - some in the male urethra and in the large ducts of some glands.
278
Describe CV of the ETC.
Protons leak back into the matrix, causing the F0 rotor to spin. This induces a conformational change in F1. Protons enter through the channel and bind the c subunits of F0. The c subunit then is forced to rotate and causes the gamma subunits to do so as well. THe gamma subunit rotates in the alpha/beta hexamer, causing them to change conformation. There are 3 beta subunits that each have an ATP synthesis site. One full rotation (~10 H+s) drives the synthesis of 3 ATPs.
279
Where does the fibularis brevis insert?
The tuberosity of the 5th metatarsal.
280
What are some fat soluble dietary antioxidants?
alpha-tocopherol (vit E), retinoids, carotenoids, ubiquinone.
281
What modifications does the golgi make?
Glycosylates lipids (this only occurs in the golgi!) O-linked glycosylation of the proteins. Modification of N-linked sugars - galactose, GlcNAc (N-acetylgalactosamine), sialic acid/NANA/N-acetylneuraminic acid (negatively charged)
282
What are the structures in the posterior mediastinum?
Descending aorta Azygous (and hemiazygous and accessory hemiazygous veins) Thoracic duct Esophagus Sympathetic trunk/splanchnic nerves Intercostal arteries Vagus nerve plexus and trunks (DATES IV)
283
Where does the trachea divide into the primary bronchi?
At the sternal angle (last bit of cartilage is called the carina).
284
What is carcinoma?
Cancer originating from epithelial cells.
285
Describe endoneurium.
Type III collagen, around individual nerve fibers, merges with basal lamina
286
What is genu varum?
Bowlegged
287
What is endomysium?
Mainly collagen type I and II. Surrounds individual muscle fibers.
288
What are some functions of apoptosis in development?
Deleting unwanted structures, sculpting specific tissues by ablating fields of cells, controlling cell numbers, eliminating cells that are nonfunctional/abnormal/dangerous (e.g. self-reactive immune cells)
289
What does the ER protein modification of a GPI do?
It causes them to clutter in the caveolae (you can also do this if you have an above average TM domain).
290
What is Lyonization?
At the 2-10,000 cell stage, random X-inactivation, turning a heterozygote female into a mosaic. A good example is X-linked anhydrotic displasia.
291
Where do you find simple squamous epithelium?
Blood/lymphatic vessels (endothelium), lining of certain body cavities (mesothelium), alveoli in lung, parietal layer of Bowman's capsule.
292
What is the G1/S-Cdk complex?
Cdk2-E
293
What is the lateral collateral ankle ligament made of?
The posterior and anterior talofibular, and the calcaneofibular ligaments.
294
What detoxifies ingested alcohol?
The SER and peroxisomes equally. This is not usually the case for things!
295
What is a confidence interval?
It corresponds to 100%-alpha.
296
Describe the JAK/Stat pathway.
Cytokines bind an RTK that has a JAN kinase that autophorphorylates itself. This recruits Stat2, which is phosphorylated, dimerizes, and goes to the nucleus to affect transcription.
297
What are colles and smith fractures?
Colles is a fracture where you fall on the palm - radius displaces dorsally. "Dinner fork deformity". Can come with median and ulnar nerve injury, carpal fracture, radioulnar joinr dislocation. Smith is a reverse Colles fracture - radius displaces ventrally. Can come with acute carpal tunner, ischemia, compressive neuropathy.
298
What type of glucose transporter is in the basal membrane?
Glucose carriers, passive transport, works with glucose concentration.
299
Where do you auscultate the superior lobe of the lung?
2nd intercostal space
300
Where does the semimembranosus insert?
The posterior medial condyle of the tibia.
301
What is a nerve fiber vs a nerve?
A nerve fiber is an axon or dendrite, a nerve is a collection of fibers (mostly axons and mostly myelinated).
302
What does the plantar reflex test?
The tibial nerve, roots L4-S2. The normal response is flexion - abnormal is Babinski's sign.
303
What is sensitivity (Se, Sn) in a screening test?
Proportion of diseased correctly classified as diseased. High Se means ruling out disease.
304
Describe the subcostal muscles.
Orientation similar to innermost intercostals, span the intercostal spaces.
305
Describe H&E stain.
Hematoxylin is basic - stains DNA, RNA, cartilage (basophilic things). Stains them blue. Eosin is acidic - stains cytoplasm, mitochondria, lysosomes, collagen, muscle (acidophilic things). Stains them pink/red/orange.
306
What do the rough and smooth part of the right atrium derive from embryologically?
Rough - original primitive atrium, Smooth - sinus venarum forms from sinus horn
307
Describe smooth muscle.
Enclosed by endomysium, full of dense bodies (alpha-actinin, also attach IFs inside the cell and adhesive junctions between cells). THey have caveolae (indentations in sarcolemma) which may act like T-tubules. It can be single-unit/visceral (gap junctions, spontaneous APs) or multi-unit (has motor units, graded contractions, cells structurally independent). Instead of a neuromuscular junction, there are axonal varicosities.
308
What is cardiolipin?
Mitochondria imports lipids from SER and makes them into cardiolipin - a "double phospholipid" with 4 FA tails. It is about 20% of the lipid in the mitochondrial IM and packs tight to help resist the PMF stress.
309
What are the anastomoses of the heart?
Right marginal branch and left marginal branchat IV branches. Posterior interventricular artery and LAD. Circumflex artery with RCA at coronary sulcus.
310
Where do you find the posterior tibial artery pulse?
Inferior to the medial malleolus in the tarsal tunnel.
311
What's the name of the deep fascia of the foot?
The pedal fascia.
312
What do the sympathetic fiber axons from L1-L2 do?
Form the lumbar splanchnic nerve -\> innervate the inferior mesenteric ganglia.
313
What does rib 1 have that typical ribs do not?
A groove for the scalene tubercle and subclavian vessels. It also only has a single facet.
314
The flow of what vessel can be damaged by a femoral neck fracture?
Medial circumflex femoral artery. Common complication is necrosis of the femoral head.
315
What are some inhibitors of complex I of the ETC?
Rotenone and amytal.
316
What is lymphoma/myeloma?
Cancer that begins in the cells of the immune system.
317
What is the gold standard?
The current best diagnostic criterion/standard used to definitively distinguish disease from wellness.
318
Where are membrane proteins translated?
On the RER. They have 20+ hydrophobic amino acids as the signal sequence. WHen the aas hit the channel, the channel will open and release the protein into the membrane. In its lifetime the protein will only come out once to be degraded by the proteosome.
319
How do vesicles travel?
Via kinesin and dynein but myosin/actin always takes over near the end.
320
Describe the formation of the lateral crest cells.
Before the folds of the neural groove fuse, some cells break away from the lateral margins to form the right and left bundle of neural crest cells which will eventually fuse into the neural crest ridge.
321
Besides wrist flexion, what are the actions of flexor carpi radialis and flexor carpi ulnaris?
Flexor carpi radialis abducts the hand, flexor carpi ulnaris adducts the hand.
322
What's the signal called that a ligand needs to be phagocytosed/opsonized?
"Eat me"
323
What is negative predictive value (NPV) in a screening test?
The proportion with negative test results who are actually well.
324
Where do all the lung parts originate from embryologically?
The epithelium is of endodermal (foregut) origin. The cartilage/muscle/CT/visceral pleura are derived from the surrounding splanchnic mesoderm. The parietal pleura is derived from the somatic mesoderm.
325
Where do the neural crest cells from the trunk region go after the closure of the neural tube?
Dorsal pathway - through the dermis to the ectoderm via holes in the basal lamina, these will form melanocytes. Ventral pathway - through the anterior half of somites, will form the sensory dorsal ganglia, sympathetic, parasympathetic, and enteric neurons, Schwann cells, and cells of the adrenal medulla.
326
Describe the thoracic aorta and its branches.
Begins left of T4 and descends posterior to esophagus. The most inferior part is dead center, esophagus displaced left. Anterior unpaired branches - to gut, pericardial, mediastinal Lateral paired branches - to viscera other than guts Posterolateral paired branches - 3-11th posterior intercostal arteries, subcostal arteries (1 each side) that supplies diaphragm
327
What is the tetralogy of fallot?
Unequal division of truncus arteriosus caused by arnterior displacement of aorticopulmonary septum. Results in pulmonary stenosis, VSD membranous type, rightward overriding aorta, RV hypertrophy by higher pressure. Cyanotic.
328
What is the ER signal sequence?
\>8 nonpolar amino acids, usually at the N-terminus, usually cleaved by signal peptidase in the ER lumen.
329
What does the ischiofemoral ligament do?
Stabilizes the hip joint posteriorly.
330
Where is loose connective tissue found?
Beneath epithelia, around glands, around blood vessels, around various tubular organs like GI/respiratory.
331
Describe periodic acid-schiff stain.
It stains glycogen and carb containing structures magenta.
332
Where do you find the dorsalis pedis artery pulse?
Superficially over the tarsals, near the tendon of the extensor hallucis longus.
333
Describe the path of the esophagus. Where is it prone to constrict?
Goes pharynx-\>stomach. Is posterior to the left atrium, exits through esophageal hiatus at around the T10 level along with the anterior and posterior vagal trunks. Prone to constrict at level of left og left primary bronchus, at level of aortic arch, at esophageal hiatus.
334
What is pectus excavatum?
Sunken chest - due to intrauterine chest pressure, can compress lung. Appears at puberty.
335
What's the chemical mechanism of smooth muscle contraction?
Hormone ligands trigger calcium release, the calcium binds calmodulin, this binds/activates MLCK
336
What section of the mediastinum is the heart in?
The middle.
337
About how long are G1, S, and G2?
G1 varies, S is usually ~8 hours, G2 is 2.5-3 hours (the shortest one)
338
What are the similarities between cohesin and condensin?
They both bind ATP, and form rings that encircle multiple strands of DNA. At the beginning of anaphase, SEPARASE inactivates the last cohesins.
339
Where do muscle cells originate from in development?
Almost all mesodermal in origin.
340
What are Schmidt-Lanterman clefts?
Small pockets of cytoplasm left behind during Schwann cell myelination.
341
What are the regulated enzymes of glycolysis?
Hexokinase/Glucokinase (Glucose -\> G6P) Phosphofructokinase (PFK1) (F6P -\> F1,6BP) Pyruvate kinase (PEP -\> pyruvate)
342
What makes up the anatomical snuffbox?
Anteriorly - abductor pollicis longus Posteriorly - extensor pollicis longus Floor - scaphoid + radial artery Roof - superficial branch of radial nerve + cephalic vein
343
What kind of proteins to lysosomes and proteasomes each degrade?
Lysosomes - cell surface proteins, endocytosed EC proteins, autophagosomed IC proteins. Proteasomes - IC proteins that are ubiquitinated (ubiquitin signal is string of hydrophobic aas)
344
Describe the innermost intercostal/oblique muscles.
Same fiber direction as internal intercostals. Exist in lateral compartment only. Neurovascular bundle superficial to them.
345
How many ATPs are made from PDH? Directly and indirectly.
5 (2 NADH)
346
Describe collagenous fibers.
Collagen type I. Thick, dense CT found in tendons/ligaments. Stains eosinophilic by H&E.
347
What's the predominant glia in CNS white matter?
Oligodendrocytes.
348
Go over anterior/medial leg arteries/blood supply.
The common iliac artery comes from the abdominal aorta and branches into the internal and external iliac arteries. The internal iliac branches into the obturator artery. The external iliac artery branches into the femoral artery which quickly branches into the deep artery of the thigh. THe deep artery of the thigh branches into the medial circumflex femoral artery, the lateral circumflex femoral artery (in front of the femur - ascednding and descending branch), and the perforating arteries.
349
What is arthritis?
The cartilage thins, joint rubs, and the synovial joint membrane is inflamed.
350
What exits the greater sciatic foramen and enters the lesser sciatic foramen?
The pudendal nerve, internal pudendal artery/vein, nerve to obturator internus.
351
What do the anterior cardinal veins form?
SVC, internal jugular veins.
352
What are the bursae of the knee?
Fluid filled sacs that act as cushions. Suprapatellar (between femur and quadriceps frmoris tendon) Subcutaneous prepatellar (between skin and anterior patella) Subcutaneous infrapatellar (between skin and tibial tuberosity) Deep infrapatellar (between patellar ligament and tibia)
353
What are the shunts in fetal heart circulation?
Ductuc venosus (bypasses liver), Foramen ovale (RA-\>LA) to bypass lungs (bad shunt), Ductus arteriosus also to avoid lungs.
354
What are stereocilia/stereovilli?
Made of actin, non-motile, much longer than microvilli. They exist in the epididymis (have an absorptive function during sperm maturation), and in the sensory hair cells in the ear (act as mechanoreceptors). They look just like cilia.
355
At what level is the horizontal fissure of the right lung?
Along the 4th rib and costal cartilage
356
Describe the left atrium.
Gets oxygenated blood from 4 pulmonary veins. Has larger smooth wall portion and smaller muscular portion than that of right atrium, auricle (rough/pectinate muscle), semilunar depression (floor of fossa ovalis).
357
Describe axonal transport within neurons.
Microtubules form tracks - anterograde (kinesin) and retrograde (dynein). Retrograde transport plays a major role in neutrophic and injury response signalling. Herpes, Rabies, Polio travel to the soma via retrograde transport.
358
Which anterior thigh muscle has its own innervating branch?
The vastus medialis - has a branch of the femoral nerve called nerve to vastus medialis.
359
Where do sympathetic nerve fibers originate from?
T1-L2.
360
Describe adipocytes in regard to connective tissue.
Fixed cells. Brown/multilocular (diminishes in first ten years of life) has tons of mitochondria and uncouples ATP. White/unilocular are a single non-membrane bound fat droplet - they work as padding, insulation, TG energy reserve, release of hormones like leptin (is considered an endocrine hormone).
361
Discuss the closure of the neural tube.
The neural folds fuse gradually in the midline at the 5th somite in the cervical region. Fusion moves out cranially and caudally into the neural tube. The anterior and posterior unfused parts are called the neuropones. The cranial one, and then the caudal one close around week 4. Failure to close can result in anencephaly and spina bifida respectively.
362
What can thymomas compress?
Right lobe - SVC (SVC syndrome, swelling os neck, face, chest wall, upper limb). Left lobe - BCV.
363
What is a diaphragmatic hernia?
The pleuroperitoneal folds fail to form properly (95% on the left side), resulting in a large posterolateral opening. Small bowel loops are present in the thoracic cavity, which hinders formation of lungs (pulmonary hypoplasia). It is the degree of hypoplasia that determines survival - 50% mortality.
364
What is the effect of glucagon?
Glucagon mainly affects the liver, it triggers a phosphorylation cascade and basically causes the opposite effects of insulin. It is active in conditions of low glucose or high amino acids. There are no receptors for it in skeletal muscle.
365
Describe CIII of the ETC.
QH2 drops one e- at a time to cyt c (can only hold one at a time, must do CoQ recycling). At the end, 2 CoQH2s drop off electrons and 4 protons are pumped out.
366
Which posterior arm muscles are specifically innervated by the posterior interosseus nerve, a continuation of the deep branch of the radial nerve?
Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis
367
What do the 3 palmar interossei do? What innervates them?
Adduct digits 2, 4, 5 and flex the metacarpophalangeal joints. The deep branch of the ulnar nerve.
368
What happens if you move the critical cutoff points in a screening test to the left?
Increase all positive test results, Se, NPV, medical referrals. Decrease all negative test results, Sp, PPV, medical referrals.
369
What are MELAS and MERRF?
Mitochondrial myopathies - mitochondrial myophathy, encephalopathy, lactic acidosis, stroke like episodes and myoclonic episodes and ragged red fibers respectively. They result from maternally inherited defects in genes encoding mitochondrial tRNAs. mtDNA mutates faster than nuclear DNA.
370
How can you get a xiphoid process fracture?
Poor CPR or contact sports. Can have dislocation of xiphisternal joint, compromised diaphragm, broken pieces can injure the heart/liver.
371
Where do you auscultate the inferior lobe of the lung?
Anteriorly in the 6/7th intercostal space Posteriorly in the triangle of auscultation (trapezius, latissimus dorsi, medial border of scapula)
372
What is special about the adductor magnus?
It has two heads and dual innervation. The hamstring division is innervated by the tibial division of the sciatic nerve. It also has an opening in its tendon called the adductor hiatus. The hamstring part originates at the ischial tuberosity and inserts on the adductor tubercle.
373
What is a negative likelihood ratio (LR-) in a screening test?
The ratio of likelihood of getting a negative test in a person without the disease to a person with. 1-Sp/Se Helps find posttest probability.
374
From what components does the diaphragm develop?
septum transversum, pleuroperitoneal membranes, dorsal mesentery of esophagus, muscular ingrowth from somites of C3-C5.
375
What does the trophoblast divide into?
The outer syncytiotrophoblast (invades the endometrium, and forms cytotrophoblastic lacunae/spaces), and the inner cytotrophoblast.
376
Describe a thoracocenteis.
AKA a pleural tap - if you want to sample fluid in the pleural cavity. Infiltrate all layers on upright patient (so fluid accumulates in costodisphragmatic recess) in expiration, go in at 9th intercostal space at midaxillary line. Can also do at 7th intercostal space at midclavicular line or 10th intercostal space at paravertebral line.
377
What is Duchenne's muscular dystrophy?
X-linked recessive mutation of the dystrophin protein, part of a complex that connects the cytoskeleton of a muscle fiber to the surrounding ECM through a cell membrane. This condition leads to muscle degeneration and premature death.
378
Which cellular processes are halted at mitosis and why?
Like everything - transcription, translation, endo/exocytosis, vesicular transport. THis is because of phosphorylation.
379
What is the medial collateral ankle ligament made of?
AKA the deltoid ligament. The posterior and alterior tibiotalar, the tibiocalcaneal, and the tibionavicular ligaments.
380
Which side of the diaphragmatic dome is higher?
The right because of the liver.
381
What does N-linked glycosylation do?
It slows down degradation rate, aids folding, creates a recognition domain.
382
Where are the lung nerves derived from?
The pulmonary plexus (parasympathetic X finers, sympathetic fibers from shympathetic chain, visceral afferent fibers from X).
383
Describe ependymal cells.
Epithelial-like cells that line ventricles and neural tube. Some of them possess cilia. They are joined by junctional complexes (tight junctions and zonula adherens). Modified ones produce CSF (mainly in the choroid plexus). They're not epithelial cells because they do not sit on a basal lamina - basal ends are elongated and extend into the neuropil.
384
When does vasculature form embryologically?
It forms from cell in yolk sac and in splanchnic mesoderm - initial connections between placenta and embryo established by week 4.
385
Describe pericarditis.
Inflammation of the pericardium, sounds like a rustle of silk.
386
What are some non free radical oxidants?
Ozone (O3), singlet oxygen, hyperchlorous acid (HOCl-), peroxynitrite (ONOO-)
387
What does superior gluteal nerve injury result in?
Weakness of hip/thigh adduction, inability to stabilize pelvis. A positive Trendelenburg's sign is when you stand on one leg and the unsupported side pelvis drops.
388
How does Arsenate effect metabolism?
HAsO4-- substitutes for phosphate and uncouples both substrate level and oxidative phosphorylation. Messes up TCA and glycolysis.
389
What is the anatomical location and auscultation site of the aortic valve?
Medial left 3rd intercostal space. Auscultation site: Right parasternal 2nd intercostal space.
390
How does lung development begin?
Around day 22, the foregut of the primitive gut tube grows ventrocaudally into the surrounding mesodern. Tracheoesophageal ridges separate the two into dorsal esophagus and trachea and ventral right and left lung buds. Around week 5, the main and secondary bronchi form - as growth occurs, primitive lungs invade pericardioperitoneal canals (which form the pleural cavities)..
391
How does the amniotic fluid leave the lungs?
Before birth, the fetus starts fetal breathing movements - the fluid is mostly absorbed into the blood and lymph, a small amount is expelled from the pressure of a vaginal birth (need to aspirate in C-sections).
392
What are the regulators of PFK1?
Activated by: AMP, ADP, F2,6BP (which also inhibits FBP1) Inhibited by: ATP, PEP, Citrate
393
What is the unhappy triad?
Torn anterior cruciate ligament, tibial collateral ligament, medial meniscus. Caused by a lateral hit to the extended knee or excessive lateral twisting of the flexed knee.
394
What does the nerve to quadratus femoris innervate?
The quadratus femoris and inferior gemellus.
395
Describe the right vagus nerve.
Enters anterior to the right subclavian artery, travels between right BCV and trachea, posterior to right hilum. Gives off right recurrent laryngeal branch - hooks under subclavian artery and ascends between trachea and esophagus.
396
Describe the brachiocephalic veins.
Right is short and runs vertically, left runs diagonally and overlies the three branches of the aortic arch. They join into the SVC posterior to the sternoclaviicular joint at the 1st right costal cartilage.
397
Describe the malate shuttle.
This is the principal mammalian shuttle for getting NADH into the mitochondria. 1) Oxaloacetate -\> malate via malate dehydrogenase (NADH-\> NAD+) 2) Malate enters, reverses back to oxaloacetate with equivalent mitochondrial enzyme (NAD+-\> NADH) 3) Oxaloacetate + glutamate -\> aspartate + alpha-KG 4) Both of these get sent out, and regenerate oxaloacetate and glutamate 5) Glutamate goes back in via glutamate/aspartate antiporter
398
Where do you auscrultate the middle lobe of the right lung?
Anteriorly in the 4th intercostal space
399
Where is the visceral pleura continuous with the parietal pleura?
At the hilum.
400
What provides cutaneous innervation to the lateral bit of the foot?
The sural nerve.
401
Where is the arch of the azygous vein? How can it be compressed?
Loops superiorly over the right lung hilum before opening into the SVC. Can be compressed by enlarged right superior tracheobronchial or hilar nodes, or by tracheal or right lung tumours.
402
What is the oblique sinus of the pericardium?
Posterior to heart, reflection of the pericardium surrounding the pulmonary veins, IVC, esophagus.
403
Describe the glycerophosphate shuttle.
1) DHAP -\> G3P via glycerophosphate dehydrogenase (NADH-\> NAD+) 2) G3P enters, gets converted back to DHAP with equivalent mitochondrial enzyme - this creates FADH2/CoQ 3) DHAP exits FADH2 is irreversible, has less redox potential, and is overall less efficient than NADH
404
What functions does pseudostratified columnar epithelium have?
Protection, secretion, absorption.
405
Where do the secretory and endocytotic pathways meet?
At lysosomes.
406
What is the equilibrium potential of potassium?
-90mV
407
Where does gluconeogenesis occur and under what conditions?
90% liver, 10% kidney. Low insulin, high glucagon/cortisol/epinephrine/norepinephrine.
408
Which components of the ETC are mobile?
Comlex II and cytochrome C.
409
Describe gap junctions.
Permit rapid exchange of small molecules - high calcium of low pH will stimulate closure. They are formed by pairs of connexons.
410
What is condensin?
It is an enzyme that condenses chromosones in their mitotic structures.
411
What is hypophosphatemia?
X-linked dominant condition - causes tickets, misshapen or bent weight-bearing bones.
412
What's interesting about phenobarbital?
The SER metabolizes it in the liver, and the hepatocyte will double in size metabolizing it - will return to normal size 24h after stopping.
413
Describe basal lamina.
ECM proteins secreted by epithelial cells that attach them to the CT lamina propria. It is so thin that it is hard to see with LM, and acts as a selective filter or as scaffolding along which regenerating epithelial cells can migrate after injury. Glycoproteins secreted by epithelial cells are major components (type IV collagen, perlacon, laminin, entactin). Integrins project and bind laminin, perlacon has negatively charged side chains, which gives the basal lamina a fixed negative charge.
414
What is a type I error?
Rejecting a true null hypothesis. Probability is alpha. Probability of correct acceptance is 1-alpha.
415
How is the ETC regulated?
Little regulation except for mass action - slowed by lots of ATP, by high NADH, step H+ gradient. Electrons move to sites with successively higher affinity/redox potential.
416
Define fitness.
The number of offspring of an organism that reach reproductive age, divided by the average number in the population.
417
Where do the flexor/extensor ulnaris and radialis originate?
At the base of the 5th and 2nd metacarpals respectively.
418
What are the four types of human tissue?
Muscle, nervous, epithelial, connective.
419
What are PNS satellite cells?
The primary glia - cover the surface of the soma in sensory and autonomic ganglia. Thought to play a similar role to astrocytes, supply nutrients, some protective/structural functions.
420
What are the tarsals?
Talus, calcaneus, cuboid, navicular, lateral/medial/intermediate cuneiform.
421
When does the interatrial septum form and how?
End of week 4. Septum primum grows towards the endocardial cushion (mesoderm) in the midline (hole is ostium primum). Right before fusion, ostium secundum forms at the other end. The septum secundum forms at the right of the septum primum as a crescent and then the primum functions as a primitive valve. After birth, LA pressure increases and adheres the septa to each other resulting in the fossa ovale.
422
Describe head folding.
The embryonic disc bulges into the amniotic cavity with the growth of brain vesicles, and folds cephalocaudally. The endoderm enlarges and pushes mesoderm caudally.
423
How does NO function?
Ach triggers IP3, causes calcium release, which activates NO synthase that makes NO from Arg. NO binds guanylyl cyclase, cGMP stimulates PKG, causes relaxation of smooth muscle (affects the endothelial layer).
424
Where do the anterior intercostal arteries originate from?
1-6th from the internal thoracic/mammary arteries. 7-9th from the musculophrenic arteries (also branches of the internal thoracic arteries). The superior epigastric arteries also branch from the internal thoracic arteries, and anastomose with the posterior epigastrics arounf the umbilicus.
425
How can you identify the medial view of the foot?
The sustenaculum tali with the groove for the tendon of flexor hallucis longus. Also, the medial longitudinal arch is higher than the lateral one.
426
Describe mitochondria.
They are tubular and mobile. Their sizes vary as do how many of them are per cell. depending on ATP needs. They can also be positioned right where the cell needs the ATP.
427
At what level are the oblique fissures of the lungs?
T2-6
428
How are proteins brought to be translated on the ER?
SRP binds the ER signal sequence, pauses translation, carries the ribosome with the mRNA and partial protein and takes it to the RER where it binds the SRP receptor. That recruits the translocon, SRP disengages, translation resumes and the protein is threaded through the translocon into the ER lumen.
429
What is a myocardial infarction?
Occlusion of major artery by embolus - most common is LCA (40-50%), then RCA (30-40%), then circumflex artery (15-20%).
430
Describe the mechanism of E2 of PDH. Include cofactors.
The hydroxyethyl of hydroxyethylTPP is given to the lipoyl moiety of Lipoic Acid (a cofactor of E2). The disulfide bond is broken, one S is reduced to an SH, the other S now has an acetate attached as a thioester bond. CoA comes in and replaces its S for the lipoyl sulfur and makes Acetyl Coa (and a reduced lipoyl). This occurs near a Lysine residue.
431
Describe CI of the ETC.
- NADH + FMN -\> NAD+ + FMNH. - electrons get transferred one at a time to a chain of Fe-S clusters tethered to the complex by cysteines. - uniquinone becomes ubiquinol (QH2) - This pumps 4H+s out into the IMS from the matrix. CoQ is membrane bound, CoQH2 is soluble. CII also makes QH2 but does not pump out any protons.
432
Which steps in TCA cycle require and give off water?
Citrate -\> cis-Aconitase via aconitase gives off water. cis-aconitase -\> D-isocitrate via aconitase, and fumarate -\> malate via fumarase require water.
433
What are C type chromosomes?
Smaller than B, submetacentric. 6-12, x.
434
How does Azide work?
It binds the heme in complex IV of the ETC and prevents it from working.
435
What is the EC concentration of calcium?
1.8mM
436
There are two types of sodium gates in action potentials, a normal one that opens at threshold, and then the VG ones.
Just a reminder ;)
437
Can smooth muscle regenerate?
Yes, under injury they undergo mitosis. Contractile pericytes from the walls of small blood vessels also participate in repair.
438
Where do you find simple columnar epithelium?
Stomach, small intestine, gall bladder, other organs.
439
What are the typical ribs and what do they have?
3-9. Head, neck, shaft, costal angle, transverse tubercle, articular facet, costal groove.
440
What is the pulmonary ligament?
Not a true ligament - a loose fold of mediastinal pleura inferior to the hilum. Provides space for the expansion of hilum structures.
441
What is the difference between a one-tailed and two-tailed test?
One tailed tests an increase/decrease whereas two-tailed tests a difference.
442
What's the difference between relative and absolute refractory period?
In the relative one, some VG Na+ channels are open and some are closed - but a strong enough depolarization can reopen the ones with the open inactivation gate and can make an AP with a lower amplitude. Refractory period prevents the signal propagation in the wrong direction.
443
What is Cardiac Tamponade?
A pericardial effusion can compress the heart (fibrous pericardium cannot stretch), causes Beck's Triad (hypotension (reduced SV, CO), muffled heart sounds, jugular-venous distention).
444
What makes up the sacral plexus?
The ventral rami of L4-S4. The lumbosacral trunk (L4, L5) also contributes to it.
445
How is a cyclin-Cdk complex formed? How can it be inhibited.
A cyclin binds, partially activating the CDK. CAK protein makes it fully active. Cyclin inhibitory proteins (e.g. p27) can bind the cyclin-CdK complexes and inhibit them.
446
What comprises a peripheral nerve?
axon + Schwann cells + CT + blood vessels
447
What is pleiotropy?
A mutation in one gene that has \>1 effect.
448
What is the acetabulum made of? At what age does it fuse?
The ilium, ischium, and pubis. Fuses at 25.
449
Where does the fibularis longus insert?
In the medial cuneiform and the base of the 5th metatarsal.
450
What is the general action of the muscles of the gluteal region and posterior thigh?
Laterally rotate the and abduct the thigh.
451
Name some vasoconstrictors.
Epinephrine, angiotensin, vasopressin.
452
What is the equilibrium potential of sodium?
+60mV
453
What are the regulators of hexokinase?
Activated by ADP, inhibited by G6P.
454
What do peroxisomes do?
Break down VLCFAs (\>22 carbons) through beta oxidation to octanyl-CoA and then mitochondria break down the rest. This yields H2O2 (very reactive). Catalase is only in peroxisomes, and it breaks H2O2 down.
455
What is the difference between a graded and action potential?
The amplitude of a graded one varies, propagation reduces the amplitude, and it is prone to spatial and temporal summation. It can also be inhibitory.
456
What is a normal respiration (not brady or tachypneic)?
12-20 breaths per minute.
457
What joint does inversion and eversion happen at?
The subtalar joint. It has a talocalcaneal ligament.
458
What cells make myelin?
CNS: Oligodendrocytes, one covers several axons PNS: Schwann cells, many needed per axon
459
What's the M-line of a sarcomere?
Connected to the sarcolemma.
460
What is the result of a PDH deficiency?
Lactic acidosis from accumulated pyruvate and alanine. Brain malfunction. A severe deficiency (\<20%) results in neonatal acidosis and death. A moderate (20-40%) results in brain damage with microcephaly, motor/mental retardation, optical atrophy, death in childhood. A mild deficiency (40-50%) results in carb intolerance, slowly progressive spinocerebellar ataxia.
461
Describe the G2 checkpoint.
It checks if the DNA is completely replicated and undamaged. CAK activates M-Cdk (which phosphorylates cdc25, which blocks Wee1, an inhibitor)
462
Name some vasodilators.
ANF, Acetylcholine, bradykynin.
463
How does Arsenite affect metabolism?
H2AsO3- binds to reduced lipoic acid of E2 and chelates the two sulfurs, killing the PDH activity.
464
What are phenocopies?
It looks like a known genetic disorder but it is caused by environmental influence.
465
Describe Aalpha fibers.
15um thick, myelinated, 70-120m/s (avg 100m/s). They are the primary afferent fibers from muscle spindles, efferent fibers to skeletal muscle.
466
What is the approximate size of 1 band in chromosome banding?
10M bp.
467
Describe the structure of the golgi.
In human cells, 1 on top of the MTOC on one side of the nucleus. Has 4-8 non-connected cisternae and a swarm of vesicles. The vesicles are cis (close to ER), medial, or trans (exit face).
468
How does cyanide work?
It binds to Fe3+ on hemes in complex IV of the ETC. You can get Kanzo (spastic paralysis that leads to musculoskeletal deformities) from eating cassava roots. You can treat it with an oxidizer like amyl nitrite or sodium nitrite which makes methemoglobin that CN binds to better.
469
Are chromosomes condensed in interphase?
No, except for Barr bodies and constitutive heterochromatin.
470
What is the action of tibialis posterior?
Plantarflexion and inversion of the foot.
471
What can be damaged in a posterior hip joint dislocation?
The sciatic nerve.
472
What are D type chromosomes?
Larger acrocentric. 13-15.
473
Why can't muscle supply other organs with glucose?
It lacks glucose 6 phosphatase.
474
Describe the external intercostal/oblique muscles.
"Hands in pockets" orientation. Exist posteriorly, then the membrane comes. Go from rib tubercles to the costochondral junction
475
What are B type chromosomes?
Smaller than A, submetacentric. 4-5.
476
What is gliosis?
A nonspecific reactive change of the glia in response to CNS damage, proliferate to form scar tissue. Mostly this is astrocytes but sometimes also microglia and oligodendrocytes. They are a feature in MS, stroke. To see astrocytes in this, use GFAP stain - GFAP (glial fibrillary acidic protein) is an astrocyte intermediate filament.
477
Where is the most frequent site of fracture in the tibia?
The shaft.
478
How does cross-bridging occur in smooth muscle?
Ca++ binds calmodulin, activates myosin kinase, which transfers a phosphate from ATP to myosin heads. Relaxation by myosin phosphatase.
479
Tell me about the sciatic nerve.
It is the largest nerve in the body. It has L4-S3 nerve roots. divides into the tibial and common fibular nerve in the greater sciatic foramen, under the piriformis, and travels in its divisions posterior to the knee. 12% of people have nerve variations where it branches earlier or one branch travels above/through the piriformis. Damage can be be fround medial buttock injury/surgery, trauma to posterior thigh, posterior dislocation of the femural head) It also gives rise to the superior and inferior gluteal nerves.
480
Where does aspirated fluid go to in the lung?
Upright - right posterior basal segment Supine - right superior segment
481
Describe persistent truncus arteriosus.
A partitioning of outflow tract defect, cyanotic (if untreated, death at 2 years old). Always associated with ventricular septum defects.
482
What is the Philadelphia Chromosome?
The centromere of 22 + the tip of the q arm of 9. The BcR and Abl genes combine to result in Chronic Myelogenous Leukemia (CML). Decreased leukocyte alkaline phosphatase activity - normally presents in middle age as overproduction of WBC. Initially, fatigue, night sweats, low grade fever, enlarged spleen and sometimes sternum tenderness (phase can last months-years). Accelerated phase = fever, bone pain, splenomegaly. Last phase = blast-crisis, bleeding and infection related to BM failure, failure if untreated (tyrosine kinase inhibitors).
483
Describe the thymus.
In adults, replaced by fatty tissue. Anterior to SVC and left BCV. Blood supply by the anterior intercostal and internal thoracic arteries. Veins drain into BCV, internal thoracic, inferior thyroid veins.
484
What are the plexi in the enteric nervous system?
Auerbach's/Myenteric and Meissner's/submucosal plexus.
485
What does the medial plantar nerve innervate?
Abductor hallucis Flexor digitorum brevis 1st foot lumbrical Flexor hallucis brevis
486
What is the muscle basal lamina made of?
Secreted by myocytes - made of primarily collagen IV, laminin, perlecan.
487
What is mass action?
The rule that if substrate concentration is high and product concentration low, then movement through the pathway will be favoured if the enzyme is not saturated.
488
What is the outer mitochondrial membrane permeable to?
Anything under 5000 Da because it has porins that are "leaky"/always open.
489
What is the action of the dorsal interossei?
Abduct 2-4 digits and flex metatarsophalangeal joints.
490
Where does the fetal part of the placenta differentiate from?
The chorionic plate
491
What is perimysium?
Mainly collagen I. Surrounds muscle fascicles.
492
What is the structure of pyruvate dehydrogenase (PDH)?
8 trimers of E2 (lipoamide reductase/transacetylase), 6 dimers of E3 (dihydrolipoyl dehydrogenase), 12 dimers of E1 (pyruvate decarboxylase).
493
What are the 3 critical cutoff points in screening tests?
1) maximal accuracy 2) 100% Se and NPV (extreme value for diseased) 3) 100% Sp and NPV (extreme value for well)
494
What structures can a sternal fracture damage?
Superior mediastinal ones.
495
What are all the glia? Which is the most common?
CNS: Oligodendrocytes, astrocytes (most common), microglia, ependymal. PNS: Schwann cells and satellite cells.
496
Where should the sperm meet the egg?
In the infundibulum.
497
What is the glycocalyx?
All the covalently added carbs on proteins and lipids form the glycocalyx around the plasma membrane - serves a protective function, important in cell recognition.
498
Where does the popliteus originate and insert?
Origin: lateral condyle of femur Insertion: Proximal posterior tibia
499
What are myofibroblasts?
A contractile non-muscle cell, has vimentin intermediate filaments. Resembles fibroblasts but possess more actin/myosin. May contract in wound healing.
500
What is peristalsis?
Smooth muscle is often arranged into sheets of opposing fibers, forming a longitudinal and circular layer. The contraction of the opposing layers can result in the rhythmic contraction known as peristalsis.
501
What are regulators of PDH?
Active when dephosphorylated. Ca2+ activates phosphatase and Pyruvate inhibits kinase. ATP, AcCoA, NADH, citrate, malonyl-CoA activate kinase.
502
Where are the pleura prone to injury?
Cervical pleura (rupulae), right infrasternal angle, costobertebral angles (no costal coverage inferomedial to 12th rib).
503
What innervates the piriformis?
Anterior rami of S1-S2.
504
What triggers skeletal vs smooth muscle contraction?
Skeletal always nerve innervation, smooth not always.
505
What's the H-zone of a sarcomere?
Myosin without actin.
506
What are the dimensions that the thoracic wall moves in in response to changes in intrathoracic volume and pressure?
Anteroposterior - primarily involves 2-6th ribs (convexity/concavity at costotransvere joints allow for rotational movement) Lateral - primary involves 7-10th ribs (flat costotransverse joints allow for gliding movements) Superior/inferior - primarily involves diaphragmatic dome
507
Where does the TCA cycle take place?
In the mitochondrial matrix.
508
What are the 1st layer of the muscles of the sole of the foot and where do they originate?
Abductor hallucis Flexor hallucis brevis Abductor digiti minimum Calcaneus
509
How do mitochondrial diseases typically present?
As encephalomyopathies because of the high ATP requirement of the brain and muscle. They are usually a nuclear DNA issue (~85% of the time). An mtDNA issue ~15% of the time.
510
What nerves pass superior and inferior to the inferior extensor retinaculum of the foot?
Superior - superficial fibular nerve. Inferior - deep fibular nerve.
511
Describe the common MAPK pathway.
Adaptor protein Grb2 binds an RTK via its SH2 domain. It's SH3 domain binds Ras-GEF (a small GTP binding protein that needs RasGap to hydrolyze GTP). Ras activates Raf (MAPKKK) which activates Mek (MAPKK) which activates MAPK. MAPK has lots of dosnwtream transcription effects.
512
What is the name of the deep fascia of the leg?
Crural fascia.
513
Why do cyclin concentrations drop off?
The anaphase promoting subunit ubiquitinates the cyclin and then the proteasome destroys it.
514
Why can the CNS not regenerate?
Oligodendrocytes and microglia cannot phagocytose myelin debris as well as macrophages, which are blocked by the BBB. Myelin contains inhibitors of axon regeneration. Gliosis also contributes.
515
Describe the intercostal veins.
11 posteriorly on each side. 1st drains (usually) into BCV. 2-3rd form superior intercostal trunk, which branches into the azygous to the right and the BCV to the left. 4-11th drain into the azygous/hemiazygous system, which goes into the SVC. The anterior intercostal veins drain into the internal thoracic vein. The anterior and posterior intercostal veins anastomose as they approach the vertebral column.
516
What do peroxisomes detoxify?
Phenols, formic acid, formaldehyde, 20-50% of ingested alcohol.
517
In what conditions does the trachea deviate away from the affected side?
Tension pneumothorax, pleural effusion.
518
Describe the transverse thoracic muscles.
Fiber direction opposite to innermost intercostals. Span the 2-6th intercostal spaces.
519
Describe Auerbach's plexus.
Myenteric plexus. More superficial, located between the longitudinal and the circular layers of the muscularis externa. Aids in mobility, contraction, relaxation of smooth muscle.
520
List some multiadhesive proteins.
Fibronectin (many tissues), Laminin (basal lamina and external lamina of adipocytes, muscle cells, Schwann cells), Osteopontin (bone), Entactin (basal lamina).
521
Describe the left vagus nerve.
Enters between the left common carotid and left subclavian artery, descends along left side of aortic arch - courses posterior to left hilum. Gives off left recurrent laryngeal branch - loops under aortic arch (lies posterior to ligamentum arteriosum), ascends between trachea and esophagus.
522
What are the true, false, floating ribs?
True (1-7): vertebrosternal. False (8-10): vertebrochondral Floating (11-12): vertebral (terminate in posterior abdominal muscles).
523
What provides cutaneous innervation to the sole of the foot?
The tibial nerve (medial/lateral plantar nerve, medial calcaneal nerve).
524
What is characteristic of peroxisomal disorders?
Lower plasmalogen quantity in red blood cells, increase of VLCFAs.
525
How can mannose play into metabolism?
Phosphorylated by hexokinase and then made into F6P which figures into glycolysis.
526
What intermediate filaments are in neurons?
Neurofilaments but some glia express vimentin subclass called glial fibrillary acidic proteins.
527
What is the most superior structure in the left hilum?
Pulmonary artery.
528
What do the 5th aortic arch arteries become?
Nothing usually.
529
What functions does simple squamous epithelium have?
Site for fluid, metabolite, gas exchange.
530
How do cells degrade their ECM?
Matrixins/matrix metalloproteins/MMMPs. They are balanced by inhibitory TIMPs. Degradation occurs naturally in development, growth, tissue repair, wound healing.
531
What travels inside the popliteal fossa?
From superficial -\> deep Tibial nerve, popliteal vein, politeal artery
532
What are some differences between axons and dendrites?
Axons have a constant diameter, dendrites thin out as they subdivide. Dendrites are not myelinated. Axons branch less (come from axon hillock of perikaryon) - just beyond axon hillock is the unmyelinated initial segment where the action potential begins.
533
What are caspases?
The proteins that actually chew up the cells in apoptosis. They activate a scramblase that makes phosphotidylserine exposed on the EC leaflet on the bilayer - this is an "eat me" signal.
534
What can freely diffuse in and out of the mitochondria?
Oxygen and carbon dioxide.
535
What is sarcoma?
Cancer that begins in the CT/supportive tissues much as bone, cartilage, fat, muscle (rhabsarcoma), or blood vessels.
536
How do atractyloside and bongkrekate work?
They block the ADP/ATP antiporter, causing a backup of ATP in the mitochondria which deprives the body of energy.
537
Describe receptor tyrosine kinases.
They have a TK domain on the inside of the cell, and one alpha helix TM domain. Ligand binding makes them homodimerize and autophorphorylate.
538
Describe perineurium.
Mainly type III collagen, around each nerve fascicle, comprises blood-nerve barrier
539
What functions does stratified columnar epithelium have?
Protection and secretion.
540
What is special about the fibularis tertius?
Not every person has one, its belly blends in with the extensor digitorum longus, and it does weak eversion of the foot.
541
Describe astrocytes.
Star shaped projections, the largest and most numerous of the glia. They form the glial limiting membrane/glia limitans beneath the pia mater (a 3D projection). They make contact with synapses and coordinate around blood vessels - blood brain barrier, regulate synaptic transmission, neurovascular coupling.
542
What are E type chromosomes?
Smaller than C, submetacentric. 16-18.
543
What functions does simple columnar epithelium have?
It provides some more height to the cell to separate different transport vesicles going to apical/basolateral membranes. It also functions in protection, secretion, absorption.
544
Describe lung lymphatic drainage.
Deep LNs -\> pulmonary LNs -\> Hilar/Bronchopulmonary (superficial straight here) -\> Tracheobronchial/Carinal -\> Paratracheal -\> Bronchomediastinal lymph trunk -\> Thoracic duct (L) and Right lymphatic duct -\> Venous system via R and L venous angles. Sometimes left lower lobe drains into the right superior tracheobronchial nodes.
545
What does the SER do?
Synthesize lipids, cholesterol, steroids. IT's prominent in adipocytes, adrenal cortex cells, steroid secreting cells like liver and Leydig cells.
546
What causes the hand of benediction?
Damage to the median nerve via supracondylar fracture.
547
What is it called when the placenta is in the wrong place?
Placenta previa
548
What is a type II error?
Failing to reject a false null hypothesis. Probability is beta. Probability of correct rejection is 1-beta, also called power.
549
Where do you find transitional epithelium?
Urinary bladder, ureter, upper urethra.
550
What are the carpals?
Laterally to medially and proximally to distally Scaphoid Lunate Triquetum Pisiform (not visible dorsally) Trapezium (tubercle anteriorly) Tapezoid Capitate Hamate (hook anteriorly)
551
What are the three sections of intraembryonic mesoderm around the notochord? What happens to these?
Paraxial, intermediate, and lateral. The lateral mesoderm forms holes and divices into the parietal/somatic and visceral/splanchnic layers that line the intraembryonic mesoderm. Parietal layer + overlying ectoderm will form the lateral and ventral body walls. Visceral layer + underlying endoderm will form the wall of the gut tube.
552
What is pectus carinatum?
Pigeon chest - due to CT disorders. Can cause scoliosis, links to congenital heart disease.
553
What mechanisms participate in GCPR desensitization?
Arrestin, internalization.
554
Describe zonula occludens/tight junctions.
Claudins and occludins form strands that seal the plasma membrane of 2 adjacent membranes It lets the cell sheets act as barriers and lets proteins go to only the apical or basolateral domains.
555
Where does the semitendinosus insert?
The medial tibia.
556
What is an inhibitor of complex III of the ETC?
Antimycin A.
557
What are lipofuscin granules?
Residual bodies left from lysosomal digestion, brown.
558
What is a muscular triad?
1 T-tubule (sarcolemma invagination), 2 terminal cisternae of the sarcoplasmic reticulum surrounding it.
559
What can excessive Myc cause?
Activation of Arf -\> inactivation of MdM2 (cannot bind p53 for degradation) - active p53 results in apoptosis
560
What do the posterior cardinal veins form?
Common iliac veins, root of Azygos.
561
What are cristae?
Folds in the IM of mitochondria which increase the surface area to do more electron transport.
562
How many ATPs come from a NADH and a FADH2?
2.5 and 1.5 respectively.
563
What innervates the peripheral parts of the diaphragm?
6-12th intercostal nerves.
564
Where is the respiratory chain/ATP synthase located?
On the inner membrane of the mitochondria.
565
Where do aortic arch arteries arise from embryologically?
Cranially they arise from the aortic sac, dorsally connect to left and right dorsal aortae. The dorsal aortae fuse from T4-L4 to form descending aorta (except they remain separate in region of aortic arch arteries) - right degenerates cranial-T4.
566
What is genu valgum?
Knock-kneed
567
Can skeletal muscle cells regenerate?
Yes, with the help of satellite cells that are activated and proliferate to form new fibers. Similar activity is implicated in growth after exorcise.
568
What is the S-Cdk complex?
Cdk1-A, Cdk2-A
569
How do oral rehydration salts work?
They are a glucose-electrolyte solution that works because glucose is needed to take up sodium and then water (which follows salts) by the intestines.
570
What are flippases?
They flip phospholipids from the extracellular membrane leaflet to the cytoplasmic one.
571
How is a double IVC caused? How does the body deal?
Formed when the inferior portion of the left supracardinal vein persists. The second IVC crosses at the left renal vein anteror to the aorta and joins the normal IVC.
572
Where do you do a chest tube/drain?
5/6th intercostal space at the midaxillary line. If removing air angle tube superiorly, if fluid then inferiorly.
573
What is specificity (Sp) in a screening test?
Proportion of well correctly classified as well. High Sp means ruling in disease.
574
What causes rigor mortis?
The lack of ATP and so the inability to detach actin from myosin.
575
What level is the xiphoid process at?
T10.
576
What are floppases?
They flip phospholipids from the cytoplasmic membrane leaflet to the extracellular one.
577
Describe Meissner's Plexus.
Submucosal Plexus. Deeper, between circular muscle and luminal mucosa. Regulates GI blood flow and epithelial function.
578
How can you classify glands by how they release their products?
Merocrine - simple exocytosis, usually rgulated secretion. Apocrine - apical portion of the membrane is also secreted. Holocrine - the whole cell bursts and dies and mixes with the secretory product.
579
What is receptor mediated endocytosis? Give examples.
A form of pinocytosis where the cell specifically absorbs ligands (sometimes viruses) through inward budding of PM vesicles containing proteins with receptors to the molecules being endocytosed. e.g. LDL (LDL receptor, LDL is wrapped in ApoB) and iron (transferrin)
580
Describe the actions of the PDGF receptor.
It recruits PI3K, which phosphorylates PIP2 (needs that P at the 3rd position), and turns it into PIP3. PKK1 binds PIP3 and recruits Akt, which it them phosphorylates and activates with the help of MTOR. Akt dissociates and activates Bad. Bad dissociates from apoptosis inhibitory protein (AIP), this activating it. PDGF can also activate PLCgamma (mobilizes calcium).
581
Where is an intercostal nerve block done?
Proximal to the midaxillary line above the rib between the internal and innermost intercostal muscles (before the origin of the lateral cutaneous branches).
582
What is pneumothorax?
Air in the pleural cavity. Can be tension or open - due to trauma or bronchopulmonary fistula (communication between lung and pleural cavity).
583
Where are the important places where the ribs articulate with the sternum?
2nd rib at angle of Louis/manubriosternal joint. 7th rib at xiphisternal joint.
584
What travels between the heads of the gastrocnemius?
The small saphenous vein and the sural nerve.
585
Is the default state of cells alive or dead?
Dead - they require constant signals to keep living (e.g. growth factors that increase the transcription of antiapoptotic proteins)
586
Which step in the TCA cycle creates GTP?
Succinyl-CoA -\> succinate via succinyl-CoA dehydrogenase.
587
Where is dense connective tissue found?
Regular - ligaments, tendons Irregular - dermis, organ capsules, intestine submucosa. Has relatively little substance.
588
How is pyruvate converted to Acetyl CoA?
Through pyruvate dehydrogenase. An NAD+ is required, as well as a CoA-SH.
589
What kind of damage can reactive oxygen species cause?
Proteins: they can oxidize Cys and Mets, disrupt Fe-S centers, break peptide bonds DNA: they can oxidize bases (e.g. 8-oxoguanine), cause double stranded breaks Lipids: They can oxidize polyunsaturated FAs, causing rancidity. If something oxidizes a polyunsaturated lipid, it can become malondialdehyde (a cross-linker that can cause damage). They can also create a lipid radical (lipid peroxide), which can then oxidize another lipid, continuing the cycle.
590
What factors influence power/the probability of a correct rejection of a null hypothesis?
Sample size, small variance/variability, larger differences between groups, a low alpha.
591
What innervates the posterior arm muscles?
The radial nerve.
592
How can fructose play into metabolism?
Converted into F1P and then an aldolase makes it into glyceraldehyde, which are both made to G3P.
593
Describe the pericardium.
Fibrous (tough, hard, attached to central tendon of diaphragm and sternum), serous parietal layer, serous visceral layer/epicardium. In between serous layers there is a pericardial cavity with fluid secreted by the serous mesothelium. Has transverse sinus and oblique sinus. Supplied by pericardiocophrenic arteries (run with phrenic nerves), and innervated by vagus nerces and sympathetic trunk.
594
What is the pH of the mitochondrial matrix?
7.5 - slightly basic because of all the protons pumped out.
595
What type of glucose transporter is in the apical membrane?
Na+ driven glucose symporter. Active transport, works with the sodium gradient.
596
Describe the sodium gates in action potentials.
At rest, the activation gate is closed and the inactivation gate is open. At threshold, A opens and I starts to close. Eventually, I closes (this is the peak). When it repolarizes, the gates return to normal.
597
What is the IC concentration of chlorine?
10mM
598
What are the types of aldolases and where do they work?
A (adult muscle and erythrocytes), B (liver) - a deficiency would lead to fructose intolerance, C (brain).
599
What's something that can cause apoptosis or necrosis?
UV damage.
600
What makes up the superior and inferior/diaphragmatic borders of the heart?
Superior: atria and auricles Inferior: RV (mainly) and LV
601
Where does the "true hamstring"/posterior thigh compartment originate? What are the innervations?
The ischial tuberosity and the tibial division of the sciatic nerve. Biceps femoris short head = origincates on lateral lip of linea aspera and is innervated bu fibular division of sciatic nerve.
602
Describe CIV of the ETC.
Cyt c drops off electrons at the Cu center, which are them transferred to heme a (this causes one H+ to be pumped out). This happens four times total. At heme a3, a water is made from 2 H+s. At the end, 4 H+s are pumped out into the IMS.
603
What is meiosis cadherin-mediated contact inhibition?
Both cells arrest in G1 when their cadherins are in contact, and this keeps the cells in a tissue from dividing to control organ growth.
604
What are the layers of the thoracic wall from superficial to deep?
Skin, superficial fascia, intercostal muscles, endothoracic fascia, parietal pleura (cervical, costal, mediastinal, diaphragmatic), pleural space/cavity. The visceral pleura is not part of the thoracic wall.
605
Which posterior arm muscles are specifically innervated by the deep branch of the radial nerve?
Extensor carpi ulnaris Extensor digiti minimi Supinator
606
What organs absolutely only use glucose?
The red blood cells. Also the brain, mostly, but it can deal with ketone bodies.
607
What is hypotension?
Systolic \< 90 or Diastolic \< 60
608
What is the anatomical location and auscultation site of the pulmonic valve?
Medial left 3rd costal cartilage. Auscultation site: Left parasternal 2nd intercostal space.
609
What's the difference between continuous and saltatory conduction?
Continuous - no myelin, slower. Saltatory - myelin, Rm is increased, signal propagates quicker by depolarization, is interrupted by nodes of ranvier.
610
What is the G1-Cdk complex?
Cdk4-D, Cdk6-D
611
What is the mechanism of action of antioxidants?
They react with a free radical and form a free radical that is not sufficiently reactive to cause any damage.
612
What are some indications for karyotyping?
Suspicion of recognized syndrome, unexplained mental retardation/congenital malformations, pregnancy loss, infertility, abnormality in sexual development, malignancies.
613
What's special about CAM-kinase II?
It is a dodecamer. It mediates Ca++-calmodulin signalling. It stimulated with calcium at a low frequency, you get the same response every time. But if you stimulate it with calcium at a high frequency the response steadily increases. Its subunits come off to phosphorylate things - frequent Ca++ can make more than one come off and they can phosphorylate each other.
614
Which posterior arm muscles originate at the lateral epicondyle?
Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Supinator
615
What is sex-limited inheritance?
Genes that are on autosomes and typically influence traits expressed in one sex only or traits influenced by the sex hormones.
616
Describe necrosis.
Caused by anything that depletes the cell of ATP. It results in a ragged cell appearance, and is very unlikely to just affect one isolated cell.
617
What is a trigger zone?
On muscle spindle stretch-sensitive receptors, a graded potential propagates decrementally to this zone, where if it is big enough it will trigger an AP.
618
What are the types of exocytosis?
Constitutive or regulated by ride of cytosolic calcium (triggers release of vesicles from actin binding proteins). In neurons, specific SNARE proteins need calcium to fuse. Botox degrades these.
619
What is the most common carpal fracture?
A fracture of the scaphoid - pain in th snuffbox, risk of avascular necrosis.
620
Where do you find simple cuboidal epithelium?
Kidney tubules, ducts, covering of ovary.
621
Describe the mechanism of E3 of PDH. Include cofactors.
Lipoyl is oxidized (FADH2 created which subsequently donates its H+s to make NADH). Riboflavin/B2 is a cofactor. A deficit of B2 causes fissures in the corner of the mouth, red/purple tongue inflammation, skin disease, often severe irritation of the eyes.
622
How many calciums does calmodulin bind?
4
623
Where do the coronary arteries arise from?
Arise from right and left aortic sinuses - are the first to get ox. blood.
624
What is metaplasia? What are examples?
A potentially reversible change from one fully differentiated cell type to another, implying adaptation to environmental stimuli. Smoker's couch - pseudostratified columnar with goblet cells switch to stratified squamous. Barrett's Esophagus - from GERD, normal squamous epithelium replaced by columnar with goblet cells.
625
What determines heart dominance?
The origin of the posterior interventricular artery. Right dominance (RCA) ~70%.
626
What do the sympathetic fiber axons from T5-T9 do?
Form the greater splanchnic nerve -\> innervates celiac ganglia.
627
What innervates the gluteus maximus?
The inferior gluteal nerve.
628
What is the role of 2,3 BPG in metabolism?
Only red blood cells do this, 1,3BPG is made into 2,3BPG which is then made to 3PG, generating no ATP. where ATP would normally be generated. The 2,3BPG lowers hemoglobin's affinity for oxygen in low oxygen conditions.
629
What is accuracy in a screening test?
The proportion correctly classified overall.
630
Quadriceps femoris is the anterior thigh. Quadratus femoris is the gluteal region.
Just a reminder!
631
What is the IC concentration of potassium?
150mM
632
How can IP3 have an oscillation?
Because Ca++ itself can activate IP3 receptors and cause more Ca++ release.
633
What is epimysium?
Mostly collagen I. Dense CT, exists at myotendinous junctions and is continuous with the tendon - surrounds entire muscles.
634
Describe leukocytes in regards to connective tissue.
Neutrophils, lymphocytes, basophils, eosinophils, monocytes/macrophages (can fuse e.g. osteoclasts, foreign giant cells). Depending on the type of CT that monocytes wander into, they will differentiate into a different cell type - mononuclear phagocyte system. Macrophages are APCs (Dendritic cells best APCs). Diapedesis is the process by which they enter.
635
When does gastrulation begin?
At the end of week 2.
636
What are G type chromosomes?
Small acrocentric. 21,22,Y.
637
What is Mallory Trichrome?
Stains collagen blue/green.
638
What exits through the greater sciatic foramen?
Piriformus, superior and inferior artery/vein/nerve, nerve to quadratus femoris, sciatic nerve, posterior and cutaneous nerve of thigh.
639
In the mediastinum, what's the general orientation of arteries to veins.
Arteries generally more anterior and right.
640
Name all the trisomies compatible with life.
13, 16, 18, 21, X/Y. 16 is the most common. 80% of 21s die in utero.
641
What are the thenar muscles and what innervates them?
Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis The recurrent branch of tte medial nerve.
642
What anterior thigh muscle has dual innervation?
The pectineus - femoral nerve and also obturator nerve.
643
What are lumbar ribs?
AKA 13th ribs - less than 1% of the population. Can be uni or bilateral. They articulate with the ventral surface of the lumbar transverse processes. They're rarely associated with any issues.
644
What's a way that superoxide can be generated?
Complex I can generate it - an electron leaves from FMNH2 one at a time and O2 can steal one.
645
What do monozygotic and dizygotic twins share?
Dizygotic have their own placenta, amnion, chorionic sac. Monozygotic just have their own chorionic sac, share everything else.
646
What do the hypoblast and epiblast become in gastrulation?
Hypoblasts become the endoderm, epiblasts migrate through the primitive streak and displace hypoblasts, becoming the mesoderm and ectoderm.
647
Describe the formation of the intraembryonic circulatory system.
Cytotrophoblast proliferates into primary villi, mesoderm (chorionic plate) pushes in towards decidua basalis and forms secondary villi. Mesodermal cells differentiate to form villus capillary system - tertiary villi. The tertiary villi capillaries make contact with the capillaries deveoping in the mesoderm of the chorionic plate and connecting stalk. This happens as gastrulation is progressing.
648
What do the vitelline veins form?
IVC (right), hepatic veins/sinusoids, portal vein, ductus venosus, splenic vein, inferior and superior mesenteric vein.
649
What kind of protein modifications occur in the ER?
Signal peptidase, N-linked glycosylation, replacement of TM domain with GPI (glycerophosphatidylinositol), S-S bonds to the TM portion facing the lumen (or if the protein is already in the lumen).
650
Describe multipolar neurons.
Most neurons are like this - 2 or more dendrites. All motor neurons, and CNS interneurons are multipolar.
651
Describe formation of the IVC.
Hepatic segment from hepatocardiac channel (right vietlline vein), Prerenal/Suprarenal segment from right subcardinal vein, Renal Segment from supcardinal/supercardinal anastomoses, Post/Infrarenal Segment from right supracardinal vein (controversial).
652
Where do skeletal muscle satellite cells reside?
Between the muscle fiber and external lamina.
653
What do the 4 dorsal interossei do? What innervates them?
Abduct digits 2-4 and flex the metacarpophalangeal joints. The deep branch of the ulnar nerve.
654
What is the chemiosmotic hypothesis?
Peter Mitchell in 1961 hypothesized that there is no chemical mediator for ATP synthesis, rather just a proton gradient.
655
What are some water soluble dietary antioxidants?
Ascorbic acid (vit C), uric acid, sulfhydryl compounds, phytochemicals
656
What's the only medial thigh muscle that only adducts, doesn't flex the thigh.
Adductor longus - obturator externis doesn't flex the thigh either, it laterally rotates the leg and steadies the head of femur in the acetabulum.
657
What is the role arsenic can play in glycolysis?
AsO4-- is a phosphate analog, and it can interfere with the step that makes 1,3BPG by glyceraldehyde phosphate dehydrogenase, making an unstable analog that eventually falls apart and ends up generating 3PG with no ATP made. Arsenic is therefore an uncoupler.
658
What is the action of the plantar interossei?
Adduct 3-5 digits and flex metatarsophalangeal joints.
659
What are gliomas?
Glial tumours. Most common is astrocytoma but can also have oligodendrocytoma and ependyoma. Neuronal tumours are rare but exist.
660
What are the dorsum intrinsic muscles and what innervates them?
Extensor digitorum brevis and extensor hallucis brevis. The deep fibular nerve.
661
How do structures in the head get sympathetic innervation?
Thoracic cell bodies send axons to the cervcical ganglion, postganglionic axons travel as the carotid plexus around the carotid artery. As the artery gives off branches, sympathetic nerve branch fibers piggypack off of those to get to their target organs.
662
What can cancer cells do in regards to pro/antiapoptotic factors?
They can overexpress antiapoptotic proteins, or activate PKB which can phosphorylate/inactivate proapoptotic factors.
663
What is Tay-sachs?
An autosomal recessive lysosomal disorder, common among Ashkenazim. It is a mutation in Hex A, which breaks down gangliosides. The lysosome swells, and neurons eventually die. A cherry-red spot in the macula is characteristic. Degeneration begins at 7 months, death by 4 years old.
664
What is locus heterogeneity and what is an example?
Deaf-mutism. A double heterozygote does not have the diseased phenotype - involvement involves different loci/genes.
665
What is the arrangement of the posterior thigh muscles?
Medial to lateral: semimembranosus, semitendinosus, biceps femoris.
666
What does the embryoblast divide into?
The epiblast (columnar), and hypoblast (cuboidal) - which make up the bilaminar germ disc.
667
What is the left side equivalent of the azygous vein?
1st posterior intercostal veins (drains into BCV) Left superior intercostal veins (drain 2-4th IC spaces, into left BCV) Accessory hemiazygous veins (drain 5-8th IC spaces, sometimes left brachial veins, cross right at T7/T8 to drain into azygous) Hemiazygous veins (drain 9-12th IC spaves, crosses right at T9 to drain into azygous)
668
Describe macula adherens/desmosomes/spot adhesions.
Spot-welds, very important for holding tissue layers together. Desmosomes link cell-cell and hemidesmosomes link cell-basal lamina. In hemidesmosomes, cell adhesion is mediated by integrins and intermediate filaments.
669
What is a normal pulse?
60-100bpm.
670
What is positive predictive value (PPV) in a screening test?
The proportion with positive test results who are actually diseased.
671
How many ATPs are made from Glycolysis? Directly and indirectly.
7 (2ATP + 2NADH)
672
What is Nox2?
NADPH oxidase - forms superoxide in phagosomes on purpose to degrade things.
673
What kind of neurons are sensory./dorsal root ganglia?
Always pseudounipolar.
674
What is the name of the arterial arch on the dorsum of the foot? What's it made of?
The arcuate arch. The lateral tarsal artery and the dorsalis pedis artery, both of which come from the anterior tibial artery. It anastomoses with the deep plantar arch.
675
What is the main flexor of the thigh at the hip joint?
Iliopsoas.
676
What is the general mechanism of gluconeogenesis? What are some precursors?
Pyruvate -\> oxaloacetate -\> PEP -\> F1,6BP -\> F6P -\> G6P -\> (glucose phosphatase) glucose Precursors: lactate, alanine, glutamine, glycerol, other things that feed into the TCA cycle.
677
What is the EC concentration of chlorine?
110mM
678
How does anaerobic respiration work?
Glycolysis is carried out, then pyruvate is made into lactate to regenerate NAD+, and then it is sent to liver to be made back into glucose (Cori Cycle).
679
What is the length constant?
sqrt(Rm/Ra)
680
Describe hyaluronic acid.
A GAG made on the PM. Not sulfated, giant, links to proteoglycans and forms aggregates. Many pathogens (e.g. S. aureus) secrete hyaluronidase that turn the gel into a sol.
681
What are the three types of membranes?
Cutaneous (many layers of epithelial cells), Mucosa (has surface epithelium, lamina propria, basal lamina, and muscularis mucosae sometimes) which likes the inside of cavities that open directly to the exterior, and Serosa (has a parietal and visceral layer) that lines cavities that do not open to the external environment.
682
What are the muscles of the 2nd layer of the sole of the foot and what do they do?
Quadratus plantae - assists flexor digitorum longus in flexion of 2-5 digits Lumbricals - Flex proximal phalanges, extend middle and distal and phalanges of 2-5
683
What are the pleural recesses?
Areas of the pleural reflections not occupied by lung during deep inspiration. Costomediastinal (left\>right due to cardiac notch) and costodiaphragmatic (more pronounced around rib 8-10).
684
What's the I-band of a sarcomere?
Actin without myosin.
685
What converts the trilaminar germ disc into a roughly cylindrical embryo shape?
Lateral folding.
686
How do umbilical arteries arise embryologically?
They arise in week 4 from the connecting stalk (future umbilical cord). They are initially connected to sacral dorsal aortae, disconnect in week 5, fuse, distal part connect to proximal internal iliac arteries and form distal internal iliac arteries (also superior vesicle arteries). The distal umbilical arteries close a few minutes after birth by smooth muscle contraction after birth - fibrous proliferation closes them permanently after 2-3 months.
687
Where do the bronchial veins drain into?
Right - azygous vein Left - accessory hemiazygous vein
688
Where is the most frequent site of fracture in the fibula?
Proximal to the lateral malleolus.
689
What are the risk factors for aortic aneurysms?
Connective tissue disorders, trauma, atherosclerosis.
690
What do mitogens do?
Bind the mitogen receptor, stimulate Ras which stimulates MAPK -\> immediate early genes (Myc) -\> activates G1-Cdk
691
What is normal and febrile temperature?
36.5/98.6 38/100.4
692
What does the middle cardiac vein run with?
The posterior interventricular artery.
693
Describe bipolar neurons.
1 axon. Sensory neurons of the retina, olfactory mucosa, and inner ear are like this.
694
What is the proton chemical and electrical gradient in the mitochondrion?
~1 pH unit (-1.4 kcal/mol). 200mV (-3.3 kcal/mol)
695
What are the types of visceral motor (GVE) fibers?
Sympathetic, parasympathetic, enteric.
696
What is a pancoast tumour?
A tumour in the lung apex, can compress sympathetic trunk (Horner's syndrome - miosis, ptosis, anhydrosis), brachial plexus (lower trunk injuries), or subclavian artery/vein (pulselessness, pallor, pain).
697
What muscle(s) are innervated by the superior gluteal nerve?
Gluteus minimus, gluteus medius, tensor fascia latae.
698
What is stage 2 hypertension?
Systolic \> 166 or Diastolic \> 100
699
Describe reticular fibers.
Collagen type III. Thin, branched fibers that do not form bundles - form supportive networks instead. Found in soft tissue, around nerves, small blood vessels, muscle cells. Argyrophilic in silver stain. Ehlers-Danlos type III (the least severe form) is caused by these.
700
What functions does stratified cuboidal epithelium have?
Provide more robust lining than simple cuboidal.
701
What's the relationship between cancer progression and mutation?
As cancers progress, there is an accumulation of mutations that allow faster cell divisions, spread to other locations, etc. Visible as aneuploidy, homogenously staining regiong, double minutes, marker chromosomes.
702
What is pleuritis?
Irritation of the parietal pleura - sharp chest pain and audible grating in cough/deep breath.
703
Describe zonula adherens.
Below the zonula occludens. Extracellularly, cadherins mediate adhesion, and intracellularly, actin filaments of the adhesion belt and terminal web form it.
704
Where do you find stratified cuboidal epithelium?
It's rare - you can find it in the larger ducts of various glands including the pancreas, salivary glands, sweat glands.
705
What is the general structure of collagen?
Repeating Gly X Y sequence where X/Y is often proline or hydroxyproline. THe subunits are assembled extracellularly, and fibrils form fibers form bundles.
706
Describe the apical domain of epithelia.
Can have cilia, microvilli, stereocilia. Where there is microvilli, actin filaments anchor into a terminal web/adhesion belt in the zonula adherens.
707
How do synapses form?
Axonal growth cone extends to find target - actin polymerization forms lamellipodium and filopodia (actin containing spikes containing receptors for + and - signals).
708
What are some functions of apoptosis in adults?
Maintaining homeostasis by maintaining cell number, eliminating cells that are damaged/mutated/infected by a virus (killer lymphocytes trigger apoptosis)
709
What is hallux valgus?
Bunions - lateral deviation of the big toe at the metatarsophalangeal joint. Caused by degenerative joint disease, wearing pointed shoes.
710
What are the lung maturation periods?
Pseudoglandular (5-17 weeks), Canalicular (16-25/28) where bronchioles begin, Terminal sac (24-birth), alveolar (birth-8) where 95% of mature alveoli are developed/formed.
711
What are some other free radical oxidants?
Peroxyl (RO2), alkoxyl (RO), hydroperoxyl (HO2), nitric oxide (NO)
712
What do the sympathetic fiber axons from T10-T11 do?
Form the lesser splanchnic nerve -\> innervates superior mesenteric ganglia.
713
What is mesothelium?
Epithelium that lines the wall and covers contents of closed cavities of the body. It is mostly simple squamous.
714
What are the length ratios of axons in the SNS vs the PNS?
Sympathetic - short preganglionic, long post. Parasympathetic: long pre, short post
715
What nerve can a hamate fracture compress?
The ulnar nerve - runs underneath it in the Guyon's canal.
716
Describe the ankle joint. What's another name for it?
aka the talocrural joint. Uniaxial, hinge-type joint. Made up of tibia, fibula, and trochlea of talus.
717
What is psoas major innervated by?
The anterior rami of L1-L3. An exception to the anterior thigh muscles.
718
Describe fibroblasts in regard to connective tissue.
Fixed cells, spindle-shaped with tapering cytoplasmic extensions, secrete all fibers/ground substance. Myofibroblasts share a lot in common with smooth muscle.
719
What happens when pro-apoptotic proteins start to cause apoptosis?
They form a channel in the mitochondrial OM. This releases cytochrome c and AIP from the IMS, which assembles other proteins to form the apoptososome.
720
What does the paraxial mesoderm form?
It is organized into somitomere blocks. Some form neuromeres (striated muscle of the face, jaw, throat), most form somites (sclerotomes - involved in vertebra formation, myotomes - muscle precursors, dermatomes - dermis of back)
721
What are the different vesicle types?
The trans-golgi sorts things into CONSTITUTIVE (no signal, goes to PM, "bulk flow"), REGULATED (goes to PM but a signal needed to release - IC calcium), LYSOSOMAL (lysosomal hydrolases, enzymes recognized because of M6P targeting sequence)
722
What is the thoracic duct?
The largest lymphatic channel in the body. originates from chyle cistern at L2 level - ascends to right of T5-L2 and thoracic aorta, left of azygous vein, posterior to esophagus, crosses to left at sternal angle, empties at left venous angle (union of left internal jugular and subclavian vein). It drains everything except the right upper quadrant (right lymphatic duct - right venous angle).
723
How can galactose play into metabolism?
Phosphorylated to Gal-1P. UDP-glucose from glycogen symthesis can be used to make UDP-galactose and G1P.
724
Describe tension pneumothorax.
Widening of the intercostal spaces, diaphragm displaced inferiorly on affected side, air enters through one-way, valve-like opening.
725
What are the parasympathetic splanchnic nerves?
Pelvic splanchnic nerves. The preganglionic axons that form these leave the ventral root before the spinal rule is formed, hence there are no parasympathetic fibers in any spinal nerves. The GVE axons then go to the hypogastric plexi and then to the target organ.
726
What is the general blood supply and innervation of the medial thigh?
Obturator artery/vein/nerve (L2-L4).
727
Where does connective tissue originate from?
Mesoderm - elongated mesenchymal stem cells.
728
How is uteroplacental circulation established?
The cells of the syncytiotrophoblast in week 2 continue to penetrate the uterine wall, erode the endothelial lining of the maternal sinusoid capillaries - and the lacunae become continuous with the sinusoids.
729
How does the anal opening form?
The cloacal membrane ruptures in week 7.
730
hen is the embryo most susceptible to abnormal development?
The embryonic period - maximum susceptibility peaks at week 5.
731
What are the causes and what is the result of tarsal tunnel syndrome?
Scar tissue, varicose veins, bone spurs, repetitive foot eversion. Results in pain/numbness at the sole of the foot, as well as weakness of the intrinsic foot muscles controlled by the tibial nerve.
732
What germ layers do epithelia derive from?
All 3.
733
Describe rib dislocation vs rib separation.
Dislocation is at the sternocostal joint or between the interchondral joints. Separation is at the costochondral joints and can displace superiorly and overlie rib above.
734
Where does the sartorius originate ahd insert?
O: Anterior superior iliac spine I: superior medial tibia
735
What's the general route for sympathetic GVE axons?
Leave lateral horn, go to ventral root, exit spinal nerve in white rami communicans, reach paravertebral ganglion travel up/down or go to same level to exit on splanchnic nerves then synapse in the prevertebral ganglia. Neuron 2 then goes to the target. If innervating blood vessels or sweat glands, it will synapse in the paravertebral ganglion and then traven on gray rami communicans to leave sympathetic chain and enter spinal nerve. Some heart and lung innervating neurons also synapse in the paravertebral ganglia.
736
What are the innervations to the heart?
Vagus (parasympathetic), Sympathetic (presynaptic T1-T4 and postsynaptic cervical and superior thoracic ganglia), Visceral afferent fibers (travel with sympathetic fibers).
737
How does the affected limb in an acquired hip joint dislocation present?
Shorter and medially rotated.
738
What is the primary cause of tail folding of the embryo?
The growth of the caudal part of the neural tube. This results in the demarcation of the foregut, hindgut, midgut.
739
Describe a left SVC (not double SVC).
There is no left BCV, and a huge coronary sinus.
740
What are the muscles of the quadriceps femoris? Where do they insert?
Rectus femoris, vastus medialis, vastus intermedialis, vastus lateralis. They insert on the patella via the quadriceps femoris tendon, and the tibial tuberosity via the patellar ligament.
741
What do the carpals articulate proximally with?
The radius.
742
What is the most superior structure in the right hilum?
Eparterial bronchus.
743
Describe the right coronary artery.
Descends in interventricular groove. Supplies RA. Gives off SA nodal branch (supplies PT, SA node), Right marginal branch (supplies RN, apex, anastomoses at IV branches), Posterior Interventricular branch (supplies RV, LV, posterior 1/3 of IV septum. Anastomoses with LAD. Gives off AV node.)
744
What is prehypertension?
Systolic 120-139 Diastolic 80-89
745
Where is the tarsal tunnel? What is inside it?
Posterior to the medial malleolus between calcaneus and flexor retinaculum. Tibialis posterior tendon Flexor digitorum longus tendom Posterior tibial artery + vein Posterior tibial nerve Flexor hallucis longus tendon
746
What does the SER do?
- Stores Ca++, the mitochondria also do this. - Has a bound G6Phosphatase needed in gluconeogenesis. - Does most of the detox (in hepatocytes). - Has cyt-P405 in its membrane that adds O2 to molecules so they become more water soluble.
747
What muscles are affected by ulnar nerve damage at the wrist?
Hypothenars, interossei, 3rd and 4th lumbricals. Cannot flex the metacarpophalangeal joints of 4-5, extend the IPs, or move digit 5.
748
What makes up the cutaneous innervation of the posterior thigh and knee?
The posterior cutaneous nerve of the thigh (S1-S3).
749
What innervates the costal parietal pleura?
1-12th intercostal nerves.
750
What does the small cardiac vein run with?
The right marginal artery.
751
What is Troisier's sign?
Enlarged Virchow's nodes (left supraclavicular fossa). Indicative of GI cancer that has spread through the thoracic duct.
752
What is the general action of the anterior leg muscles? What is the blood supply/innervation?
Dorsiflexion. Anterior tibial artery/vein, deep fibular nerve.
753
How does lymph drainage of the palm go?
Palm to dorsal.
754
What activates pyruvate kinase?
The accumulation of F1,6BP.
755
What is a positive likelihood ratio (LR+) in a screening test?
The ratio of likelihood of getting a positive test in a person with a disease to the person without. Se/1-Sp Helps find posttest probability.
756
What comprises a ganglion?
soma + axons + loose fibrocollagenous support tissue + PNS glia
757
Describe the right atrium.
Gets deoxygenated blood from the SVC, IVC, coronary sinus, anterior cardiac veins. Has smooth segment (sinus venarum), rough segment (pectinate muscle), crista terminalis, fossa ovalis, auricle (space for increased blood flow).
758
What causes asthma?
Leukotrienes by respiratory mast cells.
759
Where does glycolysis take place?
In the cytoplasm.
760
Which steps in the TCA cycle create NADH?
D-isocitrate -\> alpha-ketoglutarate via isocitrate dehydrogenase. alpha-ketoglutarate -\> succinyl-CoA via alpha-KG dehydrogenase. Malate -\> oxaloacetate via malate dehydrogenase. This last one is unfavourable so the oxaloacetate concentration in the mitochondria is very low but the [NAD+] = 5x[NADH]
761
What do the supracardinal veins form?
Portion of IVC, intercostal veins, rest of azygos vein (root is from posterios cardinal veins), hemiazygos vein.
762
What are the distributions of hexokinase vs glucokinase?
Hexokinase: muscle, most tissues. Glucokinase: Liver, pancreas, kidney.
763
What sugars can glucose be converted to if necessary?
Galactose and fructose (polyol pathway).
764
What supports the endosymbiotic origin hypothesis of mitochondria?
Own DNA + ribosomes, 2 membranes, neither give or receive vesicular transport.
765
What is the cortical reaction?
Only one sperm can make contact with the oocyte surface, because of the cortical reaction. It is the release of lysosomal granules from the oocyte plasma membrane, which makes it impermeable.
766
Where is Collagen type IV found?
In basal lamina.
767
Describe the knee/tibiofemoral joint.
A biaxial modified hinge joint. It has articulations at the lateral and medial condyles of the tibia with the femur, and at the patella with the femur.
768
Where do parasympathetic nerve fibers originate from?
S2-S4, CN III, VII, IX, X.
769
How can laryngeal nerves be compressed?
Aortic arch aneurysm, esophageal/tracheal/mediastinal tumours. Unilateral damage can cause hoarseness, bilateral damage can cause aphonia.
770
What is leukemia?
Cancer that starts in blood forming tissue such as bone marrow, causes large numbers of abnormal blood cells to be produced and go into the blood.
771
What are the differences between criteria for a good screening test vs a good gold standard?
Screening test acceptable for population use, inexpensive/free, done in a community setting (school, worksites), non/minimally invasive.
772
What comprises a ganglion?
soma + axons + loose fibrocollagenous support tissue + PNS glia
773
What are scramblases?
They flip phospholipids between the two bilayer leaflets equally.
774
What is the insertion of the superficial posterior leg muscles?
The calcaneus via calcaneal tendon.
775
Which is lateral between the flexor hallucis longus and the flexor digitorum longus? Besides plantarflexion, which action do they share?
The flexor hallucis longus. They both support the arch of the foot.
776
What cells are gametes derived from?
Primordial germ cells formed in the epiblast in week 2 of development. They migrate to the yolk sac which will be the future gonadal region.
777
What is BiP?
A protein in the ER homologous to HSP70 - proteins have to release from the BiP - "quality control" - misfolded ones dislocated back through the ER to be ubiquitinated and degraded.
778
What's the ratio of glial cells to neurons?
About 5-10X more glia.
779
Go over week 1 of embryo development.
The zygote goes through cleavages in the first 30 hours to form increasingly smaller blastomeres (cannot expand the ZP). At the 8 cell stage, compaction begins (tight junctions forming around the outer cell mass). The 16 cell stage at around 3 days is called the morula. In day 4, the blastocyst forms with an embryoblast (inner) and a trophoblast (outer). The ZP degenerates, and the blastocyst implants in the functional layer of the endometrium on the posterior superior wall of the uterus on day 6-7.
780
Differentiate between mallet hand, swan neck, and boutonniere deformity.
Mallet hand - hyperflexed DIP. Swan neck - hyperxetended PIP, flexed DIP. Boutonniere - flexed PIP, hyperextended DIP.
781
What are the vitelline arteries?
Paired blood vessels of the yolk sac wall. Yolk sac eventually regresses, vesself anastomose into vascular plexi, lose connection to yolk sac, join (now fused) descending aorta. They become the celiac trunk (T12 foregut structures), superior mesenteric artery (L1 midgut structures), interior mesenteric structures (L3 hindgut structures).
782
What is endothelium?
Epithelium that lines blood vessels and lymphatic vessels
