Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physio > Chapter 13 - cardiac function > Flashcards

Chapter 13 - cardiac function Flashcards

1
Q

describe vasculature

A

closed system of blood vessels; heart -> arteries -> arterioles -> capillaries -> venules -> veins -> heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

arteries

A

large branching vessels taking blood away from heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

arterioles

A

small branching vessels with high resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

capillaries

A

site of exchange between blood and tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

venules

A

small converging vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

veins

A

relatively large converging vessels that conduct blood to heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

erythrocytes

A

red blood cells transport oxygen and carbon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

leukocytes

A

white blood cells defend body against pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

platelets

A

cell fragments important in clotting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

plasma

A

fluid and solutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what percentage do the cells in blood make up as volume

A

50% of blood volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe pulmonary circuit

A

supplied by right heart. blood vessels from heart to lungs, and from lungs to heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe systemic circuit

A

supplied by left heart. blood vessels from heart to systemic tissues, and from tissues to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what happens in pulmonary capillaries

A

deoxygenated blood enters pulmonary capillaries. Oxygen from air diffuses to blood and CO2 diffuses from blood to air. blood leaving lungs in oxygenated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what happens in systemic capillaries

A

oxygenated blood enters tissues and becomes deoxygenated and goes on to enter right heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe full path of blood flow

A

left ventricle - aortic valve - aorta - systemic circuit - vena cavae - right atrium - AV valve - right ventricle - pulmonary valve - pulmonary trunk - pulmonary circuit - pulmonary veins - left atrium - AV valve - left ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe parallel blood flow

A

aorta branches - arteries branch - arterioles branch - capillaries. fully oxygenated blood is delivered to each organ independently from one another (same for each part of the organ). independent regulation of blood flow to organs is possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe an exception to parallel blood flow

A

portal circulation - blood flows from oe capillary bed to another before returning to heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe sequence of blood flow returning from capillaries

A

capillaries - venules - veins - vena cavae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe coronary circulation

A

heart muscle is not supplied by blood in heart chambers. heart has its own supply and a set of capillaries. R. and L. coronary arteries - the very first branches from the aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe myocardial ischemia

A

decrease in blood flow through coronary arteries can lead to this (insufficient blood flow to heart muscle). chronic myocardial ischemia can lead to myocardial infraction (heart attack)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe anatomy of heart

A

located in thoraci cavity (mediastinum) diaphragm separates the abdominal cavity from thoracic cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe three layers of heart wall

A

epicardium (visceral epicardium) is outer layer that is external membrane of connective tissue. myocardium (middle) cardiac muscle layer. Endothelium inner layer of endothelial cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe walls of left ventricle

A

very large compared to right ventricle because it pumps blood for the entire body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

cardiac cycle

A

a series of events that occur in a heartbeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe pressure difference in blood flow

A

pressure difference drives blood flow from high pressure to low pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe normal direction of blood flow

A

atria contract - ventricles contract - arteries. valves prevent backward flow of blood. all valves open and close passively based on pressure gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

describe AV valves

A

right AV valve (tricuspid). left AV valve (bicuspid/mitral valve). papillary muscles and chordae tendinae (keep AV valves from prolapsing into atria during ventricular systole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what determines if AV valves open or close

A

if atrial pressure is higher than ventricular pressure than AV valves are open. if Atrial pressure is lower than ventricular pressure AV valves close.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what determines if semilunar valves are open or closed

A

if ventricular pressure is greater than aorta pressure semilunar valves are open. if ventricular pressure is lower than aorta pressure semilunar valves are closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are the two types of cells in myocardium

A

cells of the conduction system and regular cardiac contractile cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

name four types of conduction system cells

A

SA node, AV node, AV bundle (bundle of His), and Purkinje fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what makes up bulk of myocardium

A

the regular cardiac contractile cells. conduction cells are a small fraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

describe myogenic

A

cardiac muscle contractions are triggered by signals within the cardiac muscle itself, therefore contractile activity of cardiac muscle is myogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

describe autorhythmicity

A

the ability to generate contractions in its own rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what do autorhythmic cells do

A

generate signal and provide a pathway for spreading carefully timed, coordinated and fast excitation through the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

describe pacemaker cells

A

initiate action potentials by spontaneously depolarizing to threshold. set regular intrinsic rhythm to the heartbeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

describe conduction fibers

A

rapidly conduct action potentials initiated by pacemaker cells to myocardium in carefully timed and highly coordinated manner. conduction velocity = 4m/s. whereas ordinary muscle fibers have conduction velocity of 0.4 m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

where is SA node located

A

wall of the right atrium near where it joins with superior vena cava

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

where is AV noe located

A

near the tricuspid valve in the interatrial septum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

where are bundle of His and bundle branches located

A

run within interventricular septum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

where are purkinje fibers located

A

spread throughout ventricular myocardium

43
Q

name firing rate of 3 different pacemakers

A

SA node 60-100 AP/m. AV node 40-60 AP/m. Purkinje fibers 20-40 AP/m

44
Q

what is primary pacemaker of heart

A

SA node. if SA fails then AV can control the heartbeat as a backup at a slower rate. if both SA and AV node fail then Purkinje fibers can act as tertiary pacemaker but it beats very slowly

45
Q

describe the events of the spread of excitation between cells in order

A

wave of excitation - depolarization of atria - atria contract as a unit - wave of excitation - depolarization of ventricles - ventricles contract as a unit

46
Q

how is coordination of excitation possible

A

the presence of gap junctions allows for instant communication

47
Q

describe intercalated disks

A

connections between adjacent myocardial cells (desmosomes link cells mechanically to resist stress, gap junctions link cells electrically)

48
Q

where all are intercalated disks found

A

only in cardiac cells

49
Q

name 5 steps of initiation and conduction of an impulse during heartbeat

A

AP initiated in SA node. Signals spread through atrial muscle. Signal travels to AV node, AV nodal delay. Atrioventricular bundle (bundle of His). Splits into left and right bundle branches. Purkinje fibers

50
Q

what is timing of excitation from SA node to right and left atrium and AV node

A

they propagate simultaneously. It is very rapid

51
Q

how long is AV nodal delay

A

0.1 msec so atria contract before the ventricles

52
Q

what is the only electrical pathway between Atria and ventricles

A

AV node

53
Q

what are 3 most important ions for cardiac muscles

A

potassium, sodium, and calcium ions

54
Q

describe intracellular levels of important ions

A

Na low, Ca low, K high

55
Q

describe extracellular levels of important ions

A

Na high, Ca high, K low

56
Q

describe membrane permeability leading to depolarization

A

increased Na and Ca permeability makes membrane potential more positive leading to depolarization

57
Q

describe membrane permeability leading to repolarization

A

increased K permeability makes membrane potential more negative leading to repolarization and hyperpolarization

58
Q

what type of potential do autorhythmic cells have

A

pacemaker potential (unstable membrane potential) it is a slow depolarization

59
Q

name channels involved in spontaneous depolarization in pacemaker cells

A

closing K channels. Na in and K out (funny channels): net slow depolarization. Ca channels in: further depolarization to threshold.

60
Q

what happens when pacemaker cell reaches threshold

A

voltage gated fast Ca channels (L-type) in are opened. this leads to rapid depolarization (action potential)

61
Q

what happens after action potential in pacemaker cells

A

Ca channels close, Open K channels (repolarization). Repolarization activates funny channels

62
Q

describe stroke volume

A

amount of blood pushed by ventricle per beat.

63
Q

define cardiac output

A

volume of blood pumped by each ventricle per minute

64
Q

what is average CO

A

5 liters (per ventricle) per minute at rest

65
Q

what is average blood volume

A

5.5 liters

66
Q

whats possible CO for conditioned athlete during strenuous exercise

A

30-35 L/min

67
Q

how is CO regulated

A

cardiac output is entirely determined by stroke volume and heart rate. regulate through changes in heart rate and stroke volume

68
Q

describe extrinsic CO regulation

A

neural (autonomic system) and hormonal

69
Q

describe intrinsic CO regulation

A

originates within the heart - autoregulation

70
Q

how are parasympathetics transmitted to heart

A

through the vagus nerve (originating in medulla)

71
Q

what do parasympathetics innervate

A

the pacemaker cells but not the contractile cells. So the SA and AV nodes are innervated

72
Q

what determines heart rate

A

SA node firing frequency

73
Q

what is SA node firing rate without extrinsic control

A

SA node intrinsic firing rate is 100 beats/min

74
Q

describe the influences on the SA node

A

sympathetic input ups HR. parasympathetic input slows HR. at rest the parasympathetics dominate; HR around 70 bpm. during exercise/excitement sympathetic input increases and parasympathetic input decreases so HR rises. Epinephrine from adrenal gland has effects similar to sympathetics

75
Q

describe pathway of sympathetic stimulation increases in HR

A

sympathetic nerves release norepinephrine - B1 adrenergic receptors in SA node - open more of “funny” and Ca channels so more Na and Ca flow into cell - spontaneous depolarization is faster (threshold is reached faster) - HR is increased

76
Q

describe pathway of parasympathetic stimulation decreases in heart rate

A

vagus nerve releases acetylcholine - muscarinic cholinergic receptor in SA node - open more K channels and close Ca channels - decrease rate of spontaneous depolarization and hyperpolarize cell (slower to reach threshold) - heart rate is decreased

77
Q

describe hormonal control of heart rate

A

most important is epinephrine released by adrenal medulla. Has same effect as sympathetic nervous system. increases action potential frequency at SA node. increases velocity of action potential conduction in muscle fibers

78
Q

name 3 primary factors affecting stroke volume

A
  1. ventricular contractility: strength of cardiac muscle contraction 2. end-diastolic volume (preload): the volume of blood in the ventricles just before the contraction 3. afterload: arterial pressure against which the ventricles pump
79
Q

describe influence of end-diastolic volume on stroke volume

A

increased EDV stretches muscle fibers. fibers are thus closer to optimal length. optimal length leads to greater strength of contraction. this results in increased stroke volume.

80
Q

what is the significance of starling’s law

A

at any given heart rate an increase in venous return will automatically force an increase in cardiac output

81
Q

what is the cardiac cycle

A

events associated with the flow of blood through the heart during a single complete heartbeat

82
Q

name the two main periods of cardiac cycle

A

systole: ventricles contraction and diastole: ventricles relaxation

83
Q

why do valves open

A

they open passively due to pressure gradients. AV valves open when atrial pressure is greater than ventricular pressure. semilunar valves open when ventricular pressure is greater than arterial pressure

84
Q

describe phase 1 of cardiac cycle

A

ventricular filling: we start in middle of diastole. venous return, AV valves are open, blood moves from atria to ventricles, pulmonary and aortic valves are closed, passive filling until atria contract

85
Q

describe phase 2 of cardiac cycle

A

isovolumetric contraction: this is start of systole. ventricles contracting causes increase in pressure. all 4 valves are closed. no blood entering or exiting ventricle

86
Q

describe phase 3 of cardiac cycle

A

ventricular ejection. remainder of systole. pressure in ventricles exceeds pressure in arteries, semilunar valves open, blood exits ventricles (ejection), ventricular pressure falls below aortic pressure, semilunar valves close, end of systole

87
Q

describe phase 4 of cardiac cycle

A

diastole starts. ventricles relax so pressure decreases, all 4 valves are closed, no blood entering or exiting ventricles, ends with AV valves opening

88
Q

describe change in atrial and ventricular pressure for phase 1

A

ventricular filling. atrial pressure rises slowly with filling of blood, ventricular pressure (VP) stays low. small rise in VP at end due to atrial contraction

89
Q

describe change in pressures in phase 2

A

isovolumetric contraction. rapid rise in VP, atrial pressure falls

90
Q

describe change in pressures in phase 3

A

VP continues to rise and then starts to fall, atrial pressure falls further until late systole

91
Q

describe pressure changes in phase 4

A

VP pressure falls rapidly to almost zero

92
Q

describe aortic pressure (AP) in diastole (phases 4,1)

A

aortic valve closes, blood is moving from aorta to periphery, so pressure falls. lowest point in AP = diastolic pressure

93
Q

describe aortic pressure (AP) in systole (phases 2,3)

A

aortic valve opens as soon as VP pressure exceeds AP. pressure rises rapidly with ejection. highest point in AP = systolic pressure. blood flow into aorta decreases, AP decreases. aortic valve closes, systole ends. closure of aortic valve causes slight increase in AP (dicrotic notch)

94
Q

describe walls of aorta and large arteries

A

they have very elastic walls. act as pressure reservoir that stores energy during systole as elastic walls expand and releases energy during diastole as walls recoil inward.

95
Q

what does aortic pressure do

A

maintains continuous blood flow through the entire cardiac cycle

96
Q

what is end-diastolic volume (EDV)

A

volume of blood in ventricle at the end of diastole

97
Q

what is end-systolic volume (ESV)

A

volume of blood in ventricle at the end of systole

98
Q

what is stroke volume (SV)

A

volume of blood ejected from ventricle each cycle

99
Q

what is normal stroke volume

A

SV = EDV - ESV. so SV = 130ml - 60ml = 70ml

100
Q

what is ejection fraction (EF)

A

fraction of EDV ejected during heartbeat so EF = SV/EDV so EF = 70ml/130ml = 54% at rest

101
Q

describe pressure-volume curve through 4 phases

A

phase 1: ventricular volume increases from 60mL to 130mL, small pressure increment with filling phase 2: volume is constant; pressure increases dramatically phase 3: volume decreases to 60mL during ejection; pressure rises, then starts falling phase 4: pressure falls rapidly; volume is constant

102
Q

what is the soft lubb heart sound

A

it is the first sound of AV valves closing simultaneously

103
Q

what is louder dupp heart sound

A

it is the second sound of semilunar valves closing simultaneously

Physio (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions