Cardiovascular - Physiology

Front 1

what are the three structures in the carotid sheath?

Back 1

internal jugular vein (lateral)
common carotid artery (medial)
vagus nerve (posterior)

Front 2

in most cases, what supplies the SA and AV nodes?

Back 2

RCA

Front 3

80% of the time, what supplies the inferior portion of the LV via the PD artery?

Back 3

RCA (right dominant)

Front 4

when do the coronary arteries fill?

Back 4

during diastole

Front 5

what supplies the anterior interventricular septum?

Back 5

LAD

Front 6

what is the most posterior part of the heart? enlargment can cause what?

Back 6

left atrium; dysphagia

Front 7

what artery gives off large obtuse marginal branches that supply the lateral and posterior walls of the LV?

Back 7

circumflex

Front 8

what supplies the anterior 2/3 of IV septum, apical portion of anterior papillary muscle, and the anterior surface of the LV?

Back 8

LAD

Front 9

where does the RCA travel?

Back 9

in the right AV groove

Front 10

what supplies the inferior and posterior wals of the ventricles and the posterior 1/3 of the IV septum?

Back 10

posterior descending (typically a branch of RCA)

Front 11

Cardiac output = ?

Back 11

stroke volume x heart rate

Front 12

what is the Fick principle?

Back 12

CO = rate of O2 consumption/ (arterial O2 content - venous O2 content)

Front 13

how do you calculate mean arterial pressure?

Back 13

CO x TPR
also: 1/3systolic + 2/3diastolic

Front 14

pulse pressure = ?

Back 14

systolic - diastolic
(approximates stroke volume)

Front 15

stroke volume = ?

Back 15

CO/HR
EDV - ESV

Front 16

what variables affect stroke volume?

Back 16

contractility, afterload, and preload - SV CAP

Front 17

what effect does increased intracellular calcium have on contractility and SV?

Back 17

increases contractility and SV

Front 18

how does decreased extracellular sodium affect contractility and SV?

Back 18

increases contractility and SV

Front 19

5 things that decrease contractility and SV?

Back 19

1. B1 blockade
2. heart failure
3. acidosis
4. hypoxia/hypercapnea
5. Ca2+ channel blockers

Front 20

what effect does digitalis have on contractility and SV?

Back 20

increases them

Front 21

preload is equal to what volume?

Back 21

end diastolic volume

Front 22

afterload is equal to what presure?

Back 22

systolic arterial pressure (proportional to peripheral resistance)

Front 23

what effect do venous dilators (e.g. nitroglycerin) have?

Back 23

decrease preload

Front 24

what effect do vasodilators (e.g. hydralazine) have?

Back 24

decrease afterload

Front 25

this increases slightly with exercise, increased blood volume (overtransfusion), and excitement (sympathetics)

Back 25

preload

Front 26

ejection fraction = ?

Back 26

SV/EDV
(EDV-ESV)/EDV
(index of ventricular contractility)

Front 27

ejection fraction is normally greater than or equal to?

Back 27

55%

Front 28

resistance is directly proportional to what?

Back 28

viscosity

Front 29

resistance is inversely proportional to what?

Back 29

radius to the 4th power

Front 30

delta P = ?

Back 30

Q x R

Front 31

resistance = ?

Back 31

driving pressure (delta P)/flow (Q)
8(vicosity)xlength/pir4

Front 32

what does viscosity mostly depend on? when is it increased?

Back 32

hematocrit
incrased in polycythemia, hyperproteinemic states (e.g. multiple myeloma), hereditary spherocytosis

Front 33

when in the cardiac cycle is O2 consumption highest?

Back 33

isovolumetric contraction

Front 34

this is the period between mitral valve closing and aortic valve opening

Back 34

isovolumetric contraction

Front 35

this is the period between aortic valve opening and closing

Back 35

systolic ejection

Front 36

this is the period between aortic valve closing and mitral vale opening

Back 36

isovolumetric relaxation

Front 37

when does rapid filling occur?

Back 37

just after mitral valve opens

Front 38

when does slow filling occur?

Back 38

just before mitral valve closes

Front 39

when is JVD seen?

Back 39

right heart failure

Front 40

what is cardiac muscle contraction dependent on?

Back 40

extracellular calcium, which enters the cells during plateau of action potential and stimulates calcium release from the sarcoplasmic reticulum (calcium-induced calcium release)

Front 41

what is the plateau in the cardiac muscle action potential due to?

Back 41

calcium influx

Front 42

where does the pacemaker action potential occur?

Back 42

SA and AV nodes

Front 43

what accounts for the automaticity of the SA and AV nodes?

Back 43

slow diastolic depolarization - membrane potential spontaneously depolarizes as Na+ conductance increases (funny channel)

Front 44

what determines heart rate?

Back 44

slope of phase 4 in the SA node

Front 45

what are the peripheral chemoreceptors? what do they respond to?

Back 45

carotid and aortic bodies - they respond to decreased (less than 60 mmHg)/increased PCO2, decreased pH of blood

Front 46

what do central chemoreceptors respond to?

Back 46

changes in pH and PCO2 of brain interstitial fluid, which in turn are influenced by arterial CO2

Front 47

what does the aortic arch respond to? how does it transmit and to where?

Back 47

responds to increased BP; transmits via vagus to medulla

Front 48

how and to where does the carotid sinus transmit information?

Back 48

via glossopharyngeal to the medulla

Front 49

how do the central chemoreceptors respond to increased intracranial pressure?

Back 49

hypertension (sympathetic response) and bradycardia (parasympathetic response)

Front 50

what organ receives the larges share of systemic cardiac output?

Back 50

liver

Front 51

what organ receivest eh highest blood flow per gramof tissue?

Back 51

kidney

Front 52

how does the heart meet increased O2 demand?

Back 52

incrased coronary blood flow, not by increased extraction of O2

Front 53

hypoxia in the pulmonary vasculature causes what?

Back 53

vasoconstriction (unique because in other organs hypoxia causes vasodilation)

Front 54

what are the local factors in the heart that determine autoregulaton?

Back 54

O2, adenosine, NO

Front 55

what are the local factors in the brain that determine autoregulation?

Back 55

CO2 (pH)

Front 56

how do the kidneys determine autoregulation?

Back 56

myogenic and tuboglomerular feedback

Front 57

what local factors determine autoregulation in skeletal muscle?

Back 57

lactate, adenosine, K+

Front 58

what is the most important mechanism for determining autoregulation in the skin?

Back 58

sympathetic stimulation - temperature control

Front 59

what is the effect of carotid massage?

Back 59

incrases pressure on carotid artery - increasing stretch and leading to decreased HR

Front 60

what is the ultimate consequence of baroreceptors sensing hypotension?

Back 60

vasoconstriction, incrased HR, contractility, and BP - important in the response to severe hemorrhage