Week 2 Flashcards
1
Q
What is the hemodynamic version of Ohm’s Law?
A
P = Q x R P = pressure, Q = blood flow, R = resistance from organ systems
2
Q
How do you calculate cardiac output?
A
CO= (MAP - CVP)/R
CO = cardiac output, MAP = mean arterial pressure, CVP = right atrial pressure/central venous pressure, R = resistance)
3
Q
What does 100% of CO travel through?
A
the pulmonary circulation
4
Q
How do you calculate the total resistance in series?
In parallel?
A
- add them all
- take the reciprocal and add, then the reciprocal of the answer
5
Q
If you add resistors in series, what happens to the total resistance?
A
increase the total resistance
6
Q
If you add resistors in parallel, what happens to the total resistance?
A
decrease the total resistance
7
Q
How many action potentials per minute does the SA node produce?
Why is resting HR lower than that?
A
- about 100
- normal people at rest have a parasympathetic tone on the SA node via the vagus nerve
8
Q
What is the only pathway that normally connects the chambers of the heart?
A
the AV node
9
Q
Trace the pathway of electrical conduction through the heart.
A
SA node –> AV node –> bundle of His –> left and right bundle branches –> purkinje fibers –> ventricular myocytes
10
Q
What is the intrinsic rate of the AV node?
A
40-60
11
Q
What is the intrinsic rate of the purkinje fibers?
A
30-40
12
Q
Where in the heart is there a slowing of electrical signal conduction?
Why?
A
- at the AV node
- allows for full depolarization (and thus contraction) of the atria before stimulating the ventricles
13
Q
What is the slowest conduction portion of the heart?
The fastest?
A
- the AV node
- His-Purkinje system
14
Q
Explain the phases of the cardiac action potential in ventricular myocytes.
A
- Phase 0: upstroke/depolarization phase. In ventricular myocytes, due to Na influx (fast action potential)
- Phase 1: rapid repolarization, due to K flowing out
- Phase 2: plateau, Ca in, K out, little net current or voltage change
- Phase 3: repolarization, due to K out, and Ca channels closing
- Phase 4: resting/diastole, Na/Ca exchange, Na/K pump.
15
Q
Explain the phases of the cardiac action potential in SA/AV node cells.
A
- Phase 0: upstroke/depolarization phase. In SA/AV node cells, due to Ca influx via L-type Ca channels (slow action potential)
- Phase 3: repolarization, due to K out, and Ca channels closing
- Phase 4: resting/diastole/depolarization, Na/Ca exchange, Na/K pump. In nodal cells, funny (Na) channel active, and responsible for most of this phase.
16
Q
What is the difference between slow and fast action potentials in the heart, and where are they found?
A
- slow = in SA/AV node cells, due to Ca movement
- fast = in ventricular myocytes, due to Na movement
17
Q
What is the difference in membrane potential between SA/AV node cells and ventricular myocytes?
A
nodal cell’s resting membrane potential is around -65mV, as opposed to ventricular myocytes whose resting potential is around -80mV
18
Q
During which phase are ventricular myocytes in their relative refractory period?
What can increased amount of stimuli at this point cause?
A
- Phase 3
- arrhythmias
19
Q
What participates in slow Na release?
A
the funny channels
20
Q
What gives the breast its shape?
Where do they start and end?
A
- suspensory ligaments
- skin to the deep fascia
21
Q
What are the 2 main lymphatic drainages of the breast?
A
the axillary nodes and the anterior mediastinal nodes
22
Q
What border does the cephalic vein create?
A
the border between the deltoid muscle and the pectoralis major
23
Q
What is the origin of the pectoralis major?
The insertion?
The function?
A
origin- the sternum, clavicle, and ribs
insertion- humerus
function- adduction and medial rotation of the arm
24
Q
What is the origin of the pectoralis minor?
The insertion?
The function?
A
origin- ribs
insertion- coracoid process of the scapula
function- depressing the shoulder
25
What does the thoracoacromial artery do?
supplies blood to the pectoralis muscles, as well as to the shoulder and overlying skin
26
Where does the thoroacromial artery come from?
the axillary artery
27
What is the best indicator of left atrial pressure?
left capillary wedge pressure
28
What is pulse pressure an indicator of?
stroke volume
29
What are the ways you can alter the rate of the SA node?
1. alter the steepness of depolarization in phase 4
2. make the maximum diastolic potential more negative in phase 4 (will take longer to reach the more negative number and slow the HR)
3. alter the threshold for depolarization
30
What factors can increase the SA node firing rate?
1. sympathetic stimulation
2. muscarinic receptor antagonists
3. B-adrenergic receptor agonists
4. circulating catecholamines
31
What factors can decrease the SA node firing rate?
1. parasympathetic stimulation
2. muscarinic receptor agonists
3. B-blockers
32
Where does the sympathetic nervous system arise from?
| What does this include?
- the thoracolumbar spinal cord
| - T1-12 and the first few L's
33
Where does the parasympathetic nervous system arises from?
| What does this include?
- the cranial and sacral segments of the spinal cord, aka craniosacral outflow
- CN III, VII, IX, X and S2-4
34
How do parasympathetic stimuli travel?
either top down or bottom up to meet in the abdomen
35
What is the basic structure of the neural system in the somatic nervous system?
cell body in the anterior horn and lower motor neuron synapses with the target tissue
36
What is the basic structure of the neural system in the autonomic nervous system?
2 nerves are present before you get to the target tissue. You have the 1st order neuron (pre-ganglionic) that leaves the spinal cord, a synapse with a ganglion, and a 2nd order neuron (post-ganglionic) goes to the peripheral tissue
37
What is located in the lateral horn of the spinal cord?
| Where do these leave the spinal cord?
- cell bodies for the para/sympathetic/cranial nerves
| - the anterior root
38
Describe the course of the sympathetic fibers to the anterior ramus.
1. cell bodies in the lateral horn
2. leaves the spinal cord at the anterior root with the motor nerves
3. travels through the spinal cord to the anterior ramus
4. leaves the anterior ramus as a white ramus (myelinated) and goes to the sympathetic chain (ganglion)
5. leaves the sympathetic chain as a gray ramus (no myelin) to travel to the target tissues
39
Describe the course of the sympathetic fibers to the posterior ramus.
1. cell bodies in the lateral horn
2. leaves the spinal cord at the anterior root with the motor nerves
3. travels through the spinal cord to the anterior ramus
4. leaves the anterior ramus as a white ramus (myelinated) and goes to the sympathetic chain (ganglion)
5. leaves the sympathetic chain as a gray ramus and travels to the posterior ramus to innervate the intrinsic muscles of the back
40
What are the relative lengths of 1st and 2nd order neurons in sympathetic nerves?
Why?
- short 1st order, long 2nd order
| - ganglion next to the spinal cord in the sympathetic chain
41
What are the relative lengths of 1st and 2nd order neurons in parasympathetic nerves?
Why?
- long 1st order, short 2nd order
| - ganglion close to target tissues
42
What is responsible for erection of the penis?
parasympathetic S 2, 3, 4 (keeps the penis off the floor)
43
What neurotransmitter is present between 1st and 2nd order neurons?
acetylcholine
44
In a somatic nerve, what is the neurotransmitter released?
| What is the receptor?
- acetylcholine
| - N1, aka Nm, the muscle-type nicotinic receptor
45
What kinds of receptors does acetylcholine bind?
cholinergic receptors (nicotinic or muscarinic)
46
In sympathetic nerves, what is the neurotransmitter released by 1st order neurons?
What is the receptor on the 2nd order neuron?
- acetylcholine
| - N2, aka Nn, the neuron-type nicotinic receptor
47
In sympathetic nerves, what is the neurotransmitter released by 2nd order neurons ?
What is the receptor on the target tissue?
What is the exception?
- norepinephrine
- a1, a2, B1, or B2 receptors
- sweat glands, where acetylcholine is released and taken up by muscarinic receptors
48
What is the exception to the sympathetic neurotransmitter/receptor rule?
What does it use as its neurotransmitter?
What is the receptor?
- sweat glands
- acetylcholine
- muscarinic receptors
49
In what process is the N1/N2 distinction very important?
anesthesia, where you want to paralyze the muscles but not the sympathetic nervous system
50
In parasympathetic nerves, what is the neurotransmitter released by 1st order neurons?
What is the receptor on the 2nd order neuron?
- acetylcholine
| - N2, aka Nn, the neuron-type nicotinic receptor
51
In parasympathetic nerves, what is the neurotransmitter released by 2nd order neurons ?
What is the receptor on the target tissue?
- acetylcholine
| - muscarinic receptors
52
What is unique about the innervation of the adrenal medulla?
Why?
What neurotransmitter does the nerve release?
What receptor does the medulla use?
What pathway is it a part of?
- a neuron from the spinal cord directly innervates it
- allows medulla to secrete catecholamines quickly
- acetylcholine
- N2 receptors
- sympathetic
53
What are the 1st messengers in the autonomic nervous system?
acetylcholine, epineprhine, and norepinephrine
54
What effector is Galpha-s associated with?
adenylyl cyclase
55
What effector is Galpha-i associated with?
adenylyl cyclase
56
What effector is Galpha-q associated with?
phospholipase C
57
What G's do beta receptors use?
Gs
58
What G's do alpha receptors use?
Gq
59
What are common agonists for muscarinic receptors?
| Antagonists?
agonist: acetylcholine and muscarine
antagonist: atropine
60
What is the typical signalling pathway for M1/M3 receptors?
Gq
61
What is the typical signalling pathway for M2 receptors?
Gi
62
What are the common agonists for a1-adrenergic receptors?
| Antagonists?
agnoists: norepinephrine and phenylephrine
antagonists: phentolamine and prazosin
63
What are the common agonists for a2-adrenergic receptors?
| Antagonists?
agonists: norepinephrine and clonidine
antagonists: phentolamine
64
What is the typical signalling pathway for a1-adrenergic receptors?
Gq
65
What is the typical signalling pathway for a2-adrenergic receptors?
Gi
66
What are the common agonists for B1-adrenergic receptors?
| Antagonists?
agonists: epinephrine, norepinephrine, and isoproterenol
antagonists: propranolol and atenolol
67
What are common agonists for B2-adrenergic receptors?
| Antagonists?
agonists: epinephrine, isoproterenol, and albuterol
antagonists: propranolol
68
What is the typical signalling pathway for B1-adrenergic receptors?
Gs
69
What is the typical signalling pathway for B2-adrenergic receptors?
Gs
70
In the pulmonary system, what receptors are used in the para/sympathetic system?
What do they do?
- sympathetic: B2, increase airway radius
| - parasympathetic: M, decrease airway radius, increase secretions
71
In the heart, what receptors are used in the para/sympathetic system?
What do they do?
- sympathetic: B1, increase HR, increase myocyte contractility, and increase nodal conductance
- parasympathetic: M, decrease HR and decrease nodal cocnductance
72
In the blood vessels, what receptors are used in the para/sympathetic system?
What do they do?
- sympathetic: mostly a1, but also a2, B2, decrease blood vessel radius (M3 increase radius)
- parasympathetic: n/a
73
In the sweat glands, what receptors are used in the para/sympathetic system?
What do they do?
- sympathetic: M, stimulates sweat secretion
| - parasympathetic: n/a
74
What are the functions of skin?
1. protection
2. sensory
3. heat and water regulation
4. immune function
5. metabolic
6. endocrine
7. excretion
8. sexuality
75
In what layer of the skin are blood vessels located?
dermis
76
What are the layers of the epidermis from top to bottom?
1. stratum corneum (horny cell layer)
2. stratum granulosum
3. stratum spinosump
4. stratum basalis
77
Which layer of the epidermis consists of proliferating cells that are responsible for maintenance of cell populations of the dermis?
stratum basalis
78
Where is most of skin's keratin synthesized?
stratum granulosum
79
What are the components of the basal lamina?
the lamina lucida and lamina densa
80
How are basal keratinocytes attached to the basil lamina?
1. intracellular tonofilaments are attached to the desmosome plaque
2. desmosomal plaque is attached to lamina densa anchoring filaments
3. lamina densa attached to underlying reticular, collagen, and elastic fibers via anchoring fibrils (collagen VII)
81
What are the specialized cell types located in the skin?
| Which layer are they located in?
- melanocytes, Merkel cells, and Langerhans cells
| - the epidermis
82
What do Langerhans cells do?
-they are derived from bone marrow and are part of the immune system of the skin; participate in phagocytosis
83
What do Merkel cells do?
| Where are they located?
- act as mechanoreceptors
| - the basal layer of the epidermis
84
Where are melanocytes located?
the basal layer of the epidermis
85
What are the layers of the dermis?
| What are they comprised of?
- papillary dermis: loose CT
| - reticular dermis: dense irregular CT
86
Where are most skin appendages located?
in the reticular dermis
87
What are the skin appendages?
nail, hair follicles, sebaceous glands, and eccrine and apocrine sweat glands
88
What do sebaceous glands secrete?
| Where does their duct open into?
- lipids/oils
| - the hair follicles
89
What do eccrine glands secrete?
| Where does their duct open into?
- sweat
| - the surface of the skin
90
What do apocrine glands secrete?
Where does their duct open into?
Where are they located?
- viscous, odorless sex secretion
- hair follicles
- axilla and genital skin
91
Where is the main arterial blood supply to the skin located?
the subcutis
92
Which layer of the pericardium restricts expansion?
the fibrous pericardium
93
On an EKG, how much time does a small horizontal block represent?
0.04 seconds
94
On an EKG, how much time does a big horizontal block represent?
0.2 seconds (0.04 x 5)
95
Explain the +/- of the standard 3 lead system
lead I- negative right arm, positive left arm
lead II- negative right arm, positive left leg
lead III- negative left arm, positive left leg
96
In what directions do the unipolar limb leads run?
aVR- body center towards positive right arm
aVF- body center towards positive left leg
aVL- body center towards left arm
97
What does the P wave represent?
atrial depolarization
98
What does the QRS complex represent?
ventricular depolarization
99
What does the T wave represent?
ventricular myocyte repolarization
100
Where can atrial repolarization be found in the PQRST system?
hidden in the QRS complex
101
On an EKG, when does conduction from the AV node, bundle of His, bundle branches, and Purkinje fibers occur?
between the P and Q wave
102
How do you measure the PR interval?
| What does this give you information about?
- the start of the P wave to the first deflection of the Q wave
- conduction through the AV node
103
On an EKG, what difference would you expect to see if you had hypertrophy of the myocardium?
prolonged QRS complex
104
How do you calculate HR from an EKG strip?
60/R-R interval
105
What are normal values for the Mean Electrical Axis (MEA)?
-30 to +90
106
What is perpendicular to lead I?
aVF
107
What is perpendicular to lead II?
aVL
108
What is perpendicular to lead III?
aVR
109
What are the "rules of EKG"?
1. de/repolarization perpendicular to the axis of an electrode has no net deflection
2. Depolarization towards a + end gives upward deflection; repolarization towards a + end gives a downward deflection
3. larger tissue mass causes larger deflection (ventricles more than atria)
4. all EKG leads are recording the same information, just from different angles
110
What value does the lead perpendicular to the MEA have?
NET 0
111
What is the mitral valve aka?
bicuspid valve
112
What designates when end diastolic volume occurs?
when the tricuspid/bicuspid valve closes
113
What represents the maximal pressure that can be generated by the heart for any given volume?
the End Systolic Pressure Volume Relationship (ESPVR)
114
How do you calculate stroke volume?
end systolic pressure - end diastolic pressure
115
What designates when end systolic volume occurs?
when the tricuspid/bicuspid valve opens
116
How do you calculate the ejection fraction?
EF = (EDV-ESV)/EDV
117
What happens to the PV loop if you increase preload?
- end diastolic volume (EDV) increased
| - stroke volume increases
118
What happens to the PV loop if you increase afterload?
- prolong the time it takes for the aortic valve to open (isovolumetric contraction)
- decreases the stroke volume
119
What happens to the PV loop if you increase contractility?
- increase slope of ESPVR
| - increases stroke volume
120
Which takes more time of the cardiac cycle- systole or diastole?
Why?
- diastole
| - diastole is when ventricles fill, and you want sufficient time for this to happen before contraction
121
If you increase the HR, which decreases more- systole or diastole?
diastole
122
What does diastole include?
- ventricular relaxation
- ventricular filling
- atrial contraction
123
What does systole include?
- ventricular contraction
| - ventricular ejection
124
Which pleura cannot sense pain?
| Why?
- visceral pleura
| - it has no sensory innervation
125
What are the "divisions" of the pleura?
1. costal
2. cervical
3. mediastinal
4. diaphragmatic
126
What are the contents of the superior mediastinum?
1. thymus
2. trachea
3. esophagus
4. aortic arch
5. brachiocephalic veins
6. superior vena cava
7. vagus nerves
8. phrenic nerves
