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cardiac cycle and sounds Flashcards

(50 cards)

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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?

Study These Flashcards
A

end of QRS to beginning of T wave

includes no wave

amplitude gives us clinical information

22
Q

Relevance of QR interval?

Study These Flashcards
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

Study These Flashcards
A

time in millieconds

24
Q

what s the y axis on wiggers diagram

Study These Flashcards
A

volume or pressure

25
expected sequence of ECG?
P wave Pr interval QRS complex St segment T wave Isoelectric line
26
what does the aortic pressure line represent?
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
what does aortic pressure change on ECG represent?
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
when does decline in aortic pressure end? what is important about this point?
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
when does peak of aortic pressure occur, what does it represent?
systolic blood pressure after aortic valve opens
30
describe dicrotic notch
blip produced by closing of aortic valve caused by decline in aortic pressure
31
what does ventricular pressure curve start at?
0, pressure has to be lower than atrial so blood can come in
32
what happens when ventricular pressure exceeds aortic pressure?
aortic valve open, blood goes into aorta
33
after peak systolic pressure, what happens to ventricular pressure?
ventricle relaxes, pressure starts to decrease
34
when does atrial pressure increase?
shortly after p wave occurs pushes blood into ventricle
35
what is isovolumetric contraction? why does it happen?
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
when aortic valve opens, what happens?
av valves no longer being pushed into atria c wave ends abruptly
37
atrial pressure keeps increasing until what?
until AV valves open aain
38
during diastole and systole, compare atrial and ventricular pressures
atrial pressure is higher, allows blood to flow into ventricl
39
compare jugular vein pressure and atrial pressure
jugular be slightly higher so that blood can go to atria
40
what is end systolic volume?
blood in healthy ventricle, has about 50 ml in it blood pressure at end of systole
41
when is ventricular volume at its highest?
in diastole, when blood returning to heart can flow to ventricle
42
what is the measurement when ventricle is full
end diastolic volume
43
what is isovolumic contraction?
during early phase of ventricular contraction, pressure is not changing AV and aortic valves not open, blood has nowhere to go
44
what is isovolumic relaxation?
aortic/pulmonary valves close before av valves can open ventricular volume is the same as ventricular pressure drops
45
what is the rapid filling phase?
ventricular pressure drops below atrial pressure av valves open blood from atria will go into ventricles
46
when does first heart sound occur
closing of AV valves beginning of isovolumic cntraction
47
when does second heart sound occur
closing of aortic/pulmonic valves dicrotic notch
48
when does the third heart sound occur
early in diastole rapid filling
49
when does the fourth heart sound occur
blood being forced into ventricle during atrial contraction
50
what is diastole?
period of rest

CPR (9 decks)

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