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Anatomy > Ch. 20 - Heart Physiology > Flashcards

Ch. 20 - Heart Physiology Flashcards

1
Q

at what period in the cardiac cycle are all 4 valves closed?

A

isovolumetric ventricular contraction & isovolumetric ventricular relaxation

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2
Q

what type of junction connects myocardiocytes?

A

intercalated discs, gap junctions

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3
Q

what connects myocardiocytes to underlying connective tissue?

A

hemidesmisomes

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4
Q

what does depolarization mean?

A

the cell gets more positive, increase permeability for Na+ (it comes in w + charge)

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5
Q

how do cardiac muscles’ action potential differ from skeletal muscles?

A

cardiac muscles act slower than skeletal bc they must allow full contraction

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6
Q

what is spontaneous depolarization? what causes it?

A

cells can reach threshold without help because of leaky Na+ channels

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7
Q

what are the main conducting cells?

A

pacemaker cells

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8
Q

purpose of conducting cells

A

spread action potential throughout the heart

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9
Q

purpose of contractile cells

A

create force of contraction, respond to conducting cell signals

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10
Q

describe impulse conduction pathway through the heart

A 
SA Node 
AV node
atria
inter ventricular septum
purkinje fibers & papillary muscles
ventricular myocardium
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11
Q

purpose of SA node, location?

A

create HR, natural pacemaker. in right atrium

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12
Q

purpose and location of purkinje fibers

A

push blood out, help papillary muscles with contraction, in ventricles

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13
Q

purpose and location of AV node

A

pacemaker activity, delay so atria can fully contract

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14
Q

what is more serious, premature ventricular contractions (PVCs) or ventricular fibrillation?

A

ventricular fibrillation, bc the ventricles are quivering and aren’t pumping enough blood

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15
Q

possible causes of premature ventricular contractions (PVCs)

A

early firing of ectopic focus

stress, lack of sleep, irritation of heart

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16
Q

what is ectopic focus?

A

any part of heart thats doing its own thing

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17
Q

which direction do you want impulse to flow?

A

apex —> base

18
Q

other names for semilunar valves

A

pulmonary & aortic

19
Q

phases of cardiac cycle

A

atrial systole
AV valve opens, blood —> ventricles
atrial diastole, AV valve closed
isovolumetric ventricular contraction
end of ventricular systole
semilunar valves closed (isovolumetric relaxation)
AV valve opens, passive atrial filling occurs

20
Q

formula for stroke volume

A

end diastolic volume - end systolic volume

21
Q

what happens to ventricular volume during passive filling?

A

increases (because ventricles are filling w blood)

22
Q

what make up walls of ventricles?

A

papillary muscles, trabeculae carnae, purkenje fibers

23
Q

what is the name of process of listening to the heart

A

auscultation

24
Q

formula for cardiac output

A

HR x SV

25
Q

what raises HR?

A

sympathetic autonomic nervous system, epinephrine (adrenaline)

26
Q

what is stroke volume?

A

amount of blood pumped out by heart in 1 min

27
Q

what makes the “lubb” “dubb” sound

A 
lubb = AV valve closing & semilunars opening
dubb = ejection of blood from heart, semilunars closing, AV opens
28
Q

what is a heart murmur? are they always pathological?

A

irregularity of blood flow, not always bad

29
Q

what is cardiac reserve?

A

resting output - maximal output

30
Q

which branch of autonomic nervous system increases HR?

A

sympathetic (fight or flight)

31
Q

medulla oblongata role in HR

A

location of autonomic reflex centers, manipulates HR as needed

32
Q

nerve used to transmit signal through sympathetic nervous system

A

cardiac nerve

33
Q

nerve used to transmit signal through parasympathetic nervous system

A

vagus

34
Q

hormone affects on heart

A

inc HR and contractility

35
Q

what are baroreceptors?

A

sensory inputs sensitive to pressure (barometer measures pressure)

36
Q

what are chemoreceptors?

A

sensory inputs sensitive to gases (CO2 & O2)

37
Q

what is barostatic reflex?

A

dec HR bc of inc BP in head and neck region

38
Q

what is atrial reflex?

A

inc HR bc of inc venous return (more blood returning to heart through veins)

39
Q

what is preload

A

tension in ventricular myocardium right before systole

40
Q

what is afterload

A

BP in aorta & pulmonary trunk, opposes opening of semilunar valves and limits stroke volume

41
Q

what is Frank-Starling Law of the Heart

A

ventricles will adapt to contract to push out the amount of blood it receives

42
Q

which cells can spontaneous depolarize

A

conducting cells, pacemaker cells

Anatomy (15 decks)

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