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CPR > cardiac cycle and sounds > Flashcards

cardiac cycle and sounds Flashcards

1
Q

describe phase 4 of fast action potential?

A

phase 4: rest

Na,K, Ca channels are closed

cell is at resting potential

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2
Q

do cardiac myocytes have many funny sodium channels?

A

no, can’t really use them to depolarize

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3
Q

describe phase 0 of fast action potential?

A

rapid upsweep

voltage gates Na+ channels open

cell depolarizes

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4
Q

describe phase 1 of fast action potential?

A

initial repolarization

sodium channels inactivated, no Na+ enters

voltage gate k+ channels open, potassium can leave

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5
Q

describe phase 2 of fast action potential?

A

repolarization is interrupted

voltage gates Ca chanels open, calcium enters muscle cell

potassium continues to leave cell

membrane potential stabilizes at positive potential

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6
Q

describe phase 3 of fast action potential?

A

voltage gated calcium channels close

K+ channels remain open

repolarizaion completed

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7
Q

describe order of fast action potential phases

A

4,0,2,3

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8
Q

what cells does slow action potential occur in?

A

cells of conduction pathways

SA and AV nodes

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9
Q

describe phase 4 of slow action potential?

A

steady depolarization

opening of funny sodium channels

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10
Q

how can we alter heart rate? what part of the heart has most of these channels

A

how fast funny sodium channels open, SA node has the most of these channels!

thats why its the pacemaker

AV node is the backupp

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11
Q

describe phase 0 of slow action potential?

what is special about this?

A

calcium influx causes depolarization

influx is slower than Na, depolarization takes shorter amount of time

does not get as positive as in skeletal tissue

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12
Q

describe phase 1 of slow action potential?

A

initial repolarization

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13
Q

where is slow action potential phase 1 and phase 2 not found?

A

SA and AV nodal tissue

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14
Q

describe phase 2 of slow action potential?

A

calcium enters cell, allows for contraction

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15
Q

describe phase 3 of slow action potential?

A

repolarization

efflux of K+

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16
Q

what is P in an ECG?

A

atrial depolarization initiated by SA node depolarization

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17
Q

what is QRS in an ECG?

A

phase 0 depolarizations of ventricular myocytes

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18
Q

what is T wave in an ECG?

A

ventricular repolarization

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19
Q

Relevance of PR interval?

A

begin at P wave, ends at beginning of QRS wave

time it takes for depolarization to pass from atria to ventricles via AV node

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20
Q

what does PR interval represent, what happens if there is damage?

A

slow conduction velocity of AV node

damage to AV node means PR interval is prolonged

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21
Q

Relevance of ST interval?

A

end of QRS to beginning of T wave

includes no wave

amplitude gives us clinical information

22
Q

Relevance of QR interval?

A

beginnng of QRS complex to end of T wave

includes QRS complex and T wave

total time ventricular myocytes are depolarized

23
Q

what s the x axis on wiggers diagram

A

time in millieconds

24
Q

what s the y axis on wiggers diagram

A

volume or pressure

25
Q

expected sequence of ECG?

A

P wave

Pr interval

QRS complex

St segment

T wave

Isoelectric line

26
Q

what does the aortic pressure line represent?

A

at beginning, shows aortic pressure in slow decline
-no blood being ejected

initial decline in pressure is due to movement of blood from aorta into periphery

27
Q

what does aortic pressure change on ECG represent?

A

decline in pressure represents how fast blood moves to periphery

slow decline in aortic pressure means blood moving to periphery slowly

and vice versa

28
Q

when does decline in aortic pressure end?

what is important about this point?

A

when pressure of ventricle opens aortic valve and blood goes into aorta

aortic pressure is measure diastolic blood pressure
aortic and ventricular pressure are close together

29
Q

when does peak of aortic pressure occur, what does it represent?

A

systolic blood pressure

after aortic valve opens

30
Q

describe dicrotic notch

A

blip produced by closing of aortic valve

caused by decline in aortic pressure

31
Q

what does ventricular pressure curve start at?

A

0, pressure has to be lower than atrial so blood can come in

32
Q

what happens when ventricular pressure exceeds aortic pressure?

A

aortic valve open, blood goes into aorta

33
Q

after peak systolic pressure, what happens to ventricular pressure?

A

ventricle relaxes, pressure starts to decrease

34
Q

when does atrial pressure increase?

A

shortly after p wave occurs

pushes blood into ventricle

35
Q

what is isovolumetric contraction? why does it happen?

A

ventricular pressure causes av valve to bulge back into atria

causes atrial pressure to increase slightly

low pressure in atria, ventricular pressure causes closue of AV valve almost immediatel

takes some time to increase ventricular pressure to open AV valve

36
Q

when aortic valve opens, what happens?

A

av valves no longer being pushed into atria

c wave ends abruptly

37
Q

atrial pressure keeps increasing until what?

A

until AV valves open aain

38
Q

during diastole and systole, compare atrial and ventricular pressures

A

atrial pressure is higher, allows blood to flow into ventricl

39
Q

compare jugular vein pressure and atrial pressure

A

jugular be slightly higher so that blood can go to atria

40
Q

what is end systolic volume?

A

blood in healthy ventricle, has about 50 ml in it

blood pressure at end of systole

41
Q

when is ventricular volume at its highest?

A

in diastole, when blood returning to heart can flow to ventricle

42
Q

what is the measurement when ventricle is full

A

end diastolic volume

43
Q

what is isovolumic contraction?

A

during early phase of ventricular contraction, pressure is not changing

AV and aortic valves not open, blood has nowhere to go

44
Q

what is isovolumic relaxation?

A

aortic/pulmonary valves close before av valves can open

ventricular volume is the same as ventricular pressure drops

45
Q

what is the rapid filling phase?

A

ventricular pressure drops below atrial pressure

av valves open

blood from atria will go into ventricles

46
Q

when does first heart sound occur

A

closing of AV valves

beginning of isovolumic cntraction

47
Q

when does second heart sound occur

A

closing of aortic/pulmonic valves

dicrotic notch

48
Q

when does the third heart sound occur

A

early in diastole

rapid filling

49
Q

when does the fourth heart sound occur

A

blood being forced into ventricle during atrial contraction

50
Q

what is diastole?

A

period of rest

CPR (9 decks)

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