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Physiology I Block 3 > Cardiology 7.6 > Flashcards

Cardiology 7.6 Flashcards

1
Q

inward current do what to cell

A

depolarize

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2
Q

outward current do what to cell

A

repolarize

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3
Q

calcium current is voltage gated channel but modulated by

A

ligand gated channels

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4
Q

as AP is depolarizing what happens to the voltage channels

A

have a voltage threshold

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5
Q

what does calcium current do for plateau phase of AP

A

stays open

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6
Q

if you express calcium current in nerve cell can make it look like

A

cardiac cell

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7
Q

9:37

A

helps maintain

triggers relese of calcium from SR (calcium induced calcium release)

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8
Q

without calcium release cardiac cell will not

A

contract

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9
Q

sodium channels stay inactivated throughout

A

most of AP

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10
Q

what accounts for refractory period

A

sodium channels inactivated

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11
Q

depol cell and if nothing else happened what would happen to membrane potential if no potassium channels?

A

just shutting off sodium channels does not cause repol. so it wouldn’t repol.

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12
Q

whether membrane potential is depolarizing or repolarizing depends on net

A

ionic current

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13
Q

if inward current and outward currents whether big or small, if they are equal and opposite, membrane potential will be

A

stable

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14
Q

during depol net current ha to be

A

inward

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15
Q

during repol net current has to be

A

outward

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16
Q

Ito

A

potassium current

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17
Q

Ito accounts for what

A

accounts for phase 1 of AP

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18
Q

what happens to rate of phase 1 if you block Ito

A

slower

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19
Q

Ik

A

potassium current

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20
Q

Ik1

A

potassium current

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21
Q

Ik1 accounts for what when open

A

resting potential

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22
Q

if you have resting potential cell has to have open ____ channels

A

potassium

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23
Q

what happens to Ik1 to help depol cell

A

closes

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24
Q

what happens to AP if you block Ik

A

AP would get longer

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25
longer AP b/c of blocked Ik what time interval would increase
QT
26
long QT syndrome are prone to
particular arhythmia
27
antihistamine blocked an Ik and what did it do
caused death! b/c it blocked the Ik
28
all drugs have to be tested to see if they block
Ik | b/c of that histamine that blocked Ik channel and killed ppl
29
anti-arthmia in too high a dose can be pro-
arthymic
30
how does HR affect AP duration
when you increase HR, AP duration (and refractory period) they are inversely proportional
31
increase HR what happens to diastolic interval
decreased but is still preserved
32
SA node and AV node are
pacemaker cells
33
phase 4 of SA node
spontaneously depols and fires AP
34
what don't we see in SA node
the big sodium currents | calcium currents are smaller
35
upstroke of SA node is generated by acrtivation of
Ica | calcium current
36
If
"funny current" | sodium ion channel
37
draw out currents of SA node
pg 83
38
if you gave toxic dose of calcium channel blocker what will it do
block the Ica current and SA node will stop firing
39
SA node pacemaker activity is elicited by small sodium current, opens when it repolarizies, inward current dpols cell and brings it to thrshold. calcium current helps dpol towards end. activation of calcium current generates upstroke.
.
40
main way to regulate heart rate is by
autonomic nervous system
41
how does epi and noepi increase HR
increase rate of diastolic depol | increase If and Ica
42
block all beta receptors in heart and what happens to HR
wouldn't go up
43
how does acetylcholine decrease heart rate
slows rate of diastolic depol & hyperpol Vm decrease If & Ica increase Ik, Ach
44
Ach does what to heart
slows rate of depol and hyperpolarizes cell so moves further away from calcium current threshold
45
if you stimulate the vagus nerve you can stop what from firing
SA node
46
stop vagus nerve, then after a few seconds what happens
heart starts firing again b/c another pacemaker takes over
47
when pt has high or low HR it might not have anything to do with SA node but could be due to
autonomic input
48
beta 1 blockers will block effect of
sympathetic tone on HR and will slow HR
49
HR goes down with exercise due to
increased vagal tone
50
when HR above 100 beats/min called
tachycardia
51
if HR less than 60 Beats/min called
bradycardia
52
sinus arhymia means
SA node is driving the heart
53
gatekeeper b/w atria and ventricles
AV node
54
normally AP cannot propegate across
CT barrier (see pg 87)
55
wants conduction veloctiy reaches his bundles
it is very fast
56
atrial systole and ventricular systole is delayed b/c
it cannot pss through the CT it is blockin AV node
57
if ventricles are firing super fast what does AV node do
electrical filter, only allows certain ones through
58
bypass track
AP can go through and bipass
59
echo
10:07
60
rentry
echo
61
rentry is one of the most common causes of
arrhythmias
62
heart cells are electrically connected to
gap junctions
63
if gap junctions are closed
AP will not propagate
64
what can close gap junctions
calcium inside cell too high | pH too low inside
65
gap junction close would happen when
ischemia - oxygen falls CO2 goes up ATP down, lactic acid produced. calcium goes up and tends to close gap junctions
66
how does AP propagate in cardiac
initial AP is what starts the whole thing, then the rest fire the same. individual cells connected by gap junctions
67
bigger cells decrease intracellular resistance
faster conduction velocity
68
in AV node cells are smaller and what is conduction velocity
much slower
69
conduction velocity
if things in numerator go up it goes faster | if things in denominator go up it slows down
70
if amplitude is bigger
goes faster
71
small cells have ____ conduction velocity
slow
72
if resistance increases
onduction velocity decreases
73
if gap junction resistance (it's closed down) then
conduction velocity slows
74
if threshold voltage moves in positive direction what happens to conduction velocity
decreases
75
lidocaine does what
sodium channel blocker used at dentist can also be used to help some arhythmias
76
if you slowly depolarize a cell (like ventricular) sodium channels will directly from
ready to go closed state to inactivation state (hyperkalemia)
77
if you depolarize cell to -50 mv the heart cell will not
fire AP

Physiology I Block 3 (14 decks)

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