Week 2

Question 1

Indirect vs Direct Hernia

Answer 1

Indirect: Congenital vs adult, through inguinal canal and transversalis fascia, lateral to inferior epigastric artery
Direct: Not through inguinal canal, medial to inferior epigastric artery

Question 2

Neural crest derivatives

Answer 2

DRG, sympathetic trunk, collateral ganglia, adrenal medulla cells, parasympathetic ganglia, melanocytes

Question 3

Describe how a muscle is organized into cells and fasicles and how they relate to endomysium, perimysium and epimysium

Answer 3

Fibrils–>Fibers(cells)–>Fasicles–> Muscle
Endomysium- thin connective tissue layer surrounding fibers
Perimysium- surrounds fasicles and forms the larger septa within muscles
Epimysium- connective tissue surrounding the whole muscle

Question 4

Describe the internal organization of a muscle cell (skeletal)

Answer 4

Thin myofilaments- actin, tropomyosin, troponin complex
Thick myofilaments- myosin (tail consisting of 2 heads with actin/ATP binding site+ 2 tails with heavy chains)
Sarcomere- from Z line to Z line, unit of contraction
Nuclei are peripheral

Question 5

Describe the internal organization of a muscle cell (skeletal) cont.

Answer 5

Mitochondria- between myofibrils
Sarcoplasmic reticulum- smooth ER and reservoir of calcium
T-tubule- adjacent to SR, bring depolarization into interior of the cell
Triad- 2 terminal cisterna of SR + t-tubule

Question 6

Z line

A band

H band

Answer 6

Marks the boundaries of sarcomere, attached to thin and thick filaments
Length of the thick filament in the middle of the sarcomere, contant length through contraction
Center with only myosin no actin

Question 7

M line

I band

Answer 7

Overlap and interconnection of thick filaments

Consists of thin filaments. Z band bisects the I band
I+H band shorten during contraction

Question 8

Histological Basis of DMD and myasthenia gravis

Answer 8

DMD- loss of dystrophin, loss of connection of muscle cells to connective tissue
MG- autoimmune disease where antibodies block the Ach receptor sites on the sarcolemma

Question 9

Contraction Cycle

Answer 9

Nerve impulse arrives, t tubules carry depolarization to A and I band junction, L-type channel change conformation so open SR Ca channels to release calcium into sarcoplasm, calcium binds to troponin c, changes conformation of troponin I, allows myosin to bind with actin, ATP binding causes release, ATP hydrolysis causes head bending and new site attachment, P release causes head to tightly bind to actin

Question 10

Muscle Innervation

Answer 10

Terminal axon enters sarcolemma of muscle cell at synaptic cleft defined as a motor end plate, sacrolemma of synaptic cleft has numerous folds
Motor unit- number of muscle fibers supplied by 1 neuron
More motor units great force of contraction

Question 11

imaging modalities

Answer 11

x-ray radiographs, ultrasound, computerized tomography, magnetic resonance imaging, nuclear medicine, positron emission tomography

Question 12

5 x-ray densities (from black to white)

Answer 12

air, fat, soft tissue or water, calcium or bone, metal or contrast

Question 13

ALARA

Answer 13

minimize exposure to ionizing radiation

Question 14

Identify organs of the lymphatic system

Answer 14

lymph vessels, lymph nodes and nodules, thymus, spleen, bone marrow, tonsils

Question 15

Functions of the lymphatic system

Answer 15

Drain excess fluids from body tissues, re-circulate proteins from blood capillaries, absorb emuslified fat via lacteals in intestinal villi, B and T cells

Question 16

Differences between lymphatic circulation and cardiovascular circulation

Answer 16

Lymphatic vessels begin blindly with no connection to blood capillaries, endothelial cells have no basal lamina and the cells have gaps between them

Question 17

B vs. T lymphocytes

Answer 17

T cells undergo initial differenitaitonin the thymus and are involved in cell=mediated response to foreign invasion
B cells undergo initial differentiation in the bone marrow and travel to peripheral sites (plasma or memory cells)

Question 18

Primary Lymphoid Tissue

Secondary Lymphoid Tissue

Answer 18

Thymus and bone marrow

Lymph Nodes, Mucosa associated lymphatic tissue, Spleen

Question 19

Lymphatic component of Lymph nodes

Blood Vascular Component

Answer 19

Cortical afferent lymphatics, subcapsular sinus, trabecular sinus, medullary sinus, hilus and efferent lymphatics
Afferent arteriole, efferent venule

Question 20

MALT (Mucosa-associated lymphatic tissue)

Answer 20

Unencapsulated lymphoid tissue (Peyer’s patches), lamina propria lymphocytes, plasma cells and macrophages, the mucosal intra-epithelial lymphocytes, the mesenteric lymph nodes

Question 21

How do lymphatic vessels differ from blood vessels

Answer 21

Lymph vessles don’t have blood cells, extremely thin wall of mostly endothelium and CT, lymphatic vessles have valves to prevent backflow

Question 22

Spleen (White pulp)

Answer 22

Periarteriolar Lymphoid sheath (T cell)
Germinal Center (B cell)

Question 23

Spleen (Red pulp)

Answer 23

Sinus and Cords

Question 24

Development of Coelom

Function

Answer 24

Pleural and peritoneal cavities are separated by diaphagm; pleural and pericardial cavities separated by pleuropericardial folds
Function of Coelom:allows internal organs to shift around and move independently of body wall

Question 25

Contents of the mediastinum

Answer 25

pericardium, great vessels, trachea, esophagus, vagus/phrenic/sympathetic trunk nerves Middle mediastinum: pericardial sac and great vessels

Question 26

Axons that are myelinated

Answer 26

somatomotor, presynaptic sympathetic, and both processes of general sensory neurons (pseudounipolar)

Question 27

Cell process morphology

Answer 27

``` Unipolar Pseudounipolar (general and visceral sensory neurons) Multipolar (somatomotor, autonomic, and interneurons) ```

Question 28

Supporting cells PNS Schwann cells Satellite cells

Answer 28

Surrounds axons in both unmyelinated and myelinated nerves (1 schwann cell surrounds many axons if unmyelinated) Equivalent cells surrounding cell bodies

Question 29

Supporting Cells CNS Oligodendrocytes Astrocytes Microglia

Answer 29

CNS equivalent of schwann cells A scaffolding in brain tissue, derivative from neural crest Phagocytic cells

Question 30

Sheath of Schwann (neurilemma) Myelin Schmidt-Lanterman Cleft Myelin basic protein Protein O

Answer 30

Cytoplasm and organelles that are squeezed to the periphery Schwann cell membrane Narrow bands of continuity of cyoplasm from the axon to the exterior of the sheath Contribute to compacting the myelin layer creating intracellular major dense lines Extracellular intraperiod lines

Question 31

Epineurium Endoneurium Perineurium

Answer 31

Connective tissue sheath enveloping the entire nerve Delicate connective tissue surround each individual neuron and its Schwann cell neurilemma Surrounds groups of neurons, but it is not the nerve equivalent of perimycium. Contains collagen, tight junctions, and contractile filaments. Create nerve-blood barrier

Question 32

Compare and contrast malformations, deformations, and disruptions

Answer 32

ORGAN Malformation during embryonic period- poor formation of tissue, abnormal developmental process (incomplete, redundant, aberrant morphogenesis) ex. cleft lip, polydactyly, spina bifida REGIONAL Deformation during fetal period- normal tissue formation but acted upon by abnormal forces ex. mandibular asymmetry, micgrognathia Disruptions- normal tissue formation that then breaks down ex. encephalocele due to amniotic tear

Question 33

Common causes of malformation

Answer 33

single gene defects, chromosome abnormalities, multifactorial traits, maternal influences, unknown

Question 34

Sequences

Answer 34

1 single anomaly leads to another anomaly. Ex. Potter's sequence (failure of kidneys to form leads to clubbed feet)

Question 35

Pleuropericardial folds

Answer 35

Separate pleural cavities from pericardial cavity which form fibrous layer of pericardium

Question 36

Phrenic vs. Vagus

Answer 36

Innervation: Diaphragm versus Thoracic and abdominal viscera Origin: Cervical 3,4,5 versus Cranial 10 Location: Adherent to pericardium versus run alongside gut tube

Question 37

Factors in teratogenicity

Answer 37

Dose- determined by route of administeration, distribution, maternal metabolism effiency of transplacental transfer Developmental stage- before implantation (no embryo), between 2-8 weeks (development of organs), after (affects the growth or function of organ) Timing- critical period (when development is disrupted and may result in major congenital anomalies) Maternal and fetal genotype- epoxide hydrolase activity and hydantoin

Question 38

Torch agents

Answer 38

toxoplasmosis, o (syphillis), rubella, cytomegalovirus, herpes