Brainscape's Knowledge GenomeTM

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


See full index

Physiology I Block 4 > Regulation of Heart Pacemaker Potential > Flashcards

Regulation of Heart Pacemaker Potential Flashcards

1
Q

how are cardiac cells connected

A

gap junctions

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

how do impulses move in heart muscle

A

cell to cell not through nerves, via gap junctions

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

heart cells are ______ coupled

A

electrically

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

what is the RMP of SA node

A

-55 to -65 mV

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

the RMP of SA node is very ______

A

unstable

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

SA node is very leaky to

A

Na+ and Ca++

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

describe RMP of SA node

A

they are very leaky to Na+ and Ca++ so when it goes down to RMP the Na and Ca bring the RMP more positive so it will depol

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

what causes depol in SA node

A

voltage gated L type Ca++ channels

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

if current is activated at what mV

A

-60

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

when if channel opens what happens

A

sodium leadks into cell, this is for SA node

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

when SA node is -50 mv what channel opens

A

iCaT (transient)

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

what is the third channel that opens in SA node under threshold

A

iCaL

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

desribe what is happening until threshold is reached in SA node

A

if channels open which cause Na to enter, then iCaT open then IcaL open

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

what is threshold in SA node

A

about -30 mv

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

what are the phases in SA node

A

4, 0, 3, 4

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

depol of SA node is due to

A

calcium entering cell

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

what happens at peak of SA node curve

A

calcium channels close and potassium currents open

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

does the SA node contract

A

no

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

SA nodal cells fuse with:

A

atrial muscle cells
anterior interatrial band cells
internodal pathway cells

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

what is the anterior interatrial band

A

it passes from right atrium to left so they depol and contract together

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

what is the internodal pathway

A

brings the impulse from SA node to AV node

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

what is job of AV node

A

slow the impulses from SA

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

why is it important to slow down the impulses from the SA by the AV

A

so the atria can contract before the ventricle

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

describe rate of rise in AP of AV and SA node

A

SA much steeper, AV takes longer to get to threshold

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

b/w atria and ventricle is piece of fibrous tissue:

A

AV bundle

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

what is purpose of AV bundle

A

muscular connection b/w atrium and ventricle, prevents re-entry of cardiac impulses into atria from ventricle

27
Q

what is the only muscular connection b/w atria and ventricle

A

AV bundle

28
Q

why is there delta wave in WPW

A

accessory ptahway starts to depol the ventricles too soon

29
Q

after AV node where does impulse go

A

lef tand right bundle branches then purkinje fibers

30
Q

describe conduction through purkinje fibrs

A

very fast - allows the impulse to spread quickly through ventricles

31
Q

why are impulses so fast through purkinje fibers

A

bigger, more gap junctions, AP spike faster

32
Q

purkinje fibers spread the AP quickly and then it gets to ventricles and it

A

slows down a little bit

33
Q

why is there delay b/w QRS wave and ventricles contracting

A

electrical activity has to be converted to mechanical contractility, that takes time

34
Q

only thing you are measuring with ECG is

A

electrical activity

35
Q

depol vs. repol

A

depol causes another to depol, but repol just happens on its own. there is inherent property within cells that tells them how long they should stay depol

36
Q

AP duration in endocardial cells is shorter than

A

epicardial cells ( i think its actuallyosute doublencheck)

37
Q

what is intrinsic rhythmical rate

A

70-80 times/min

38
Q

what is purkinje fibers rate

A

15-40 timesmin

39
Q

why is SA node the pacemaker

A

it fires faster

40
Q

what is ectopic pacemaker

A

anther area of heart fires faster than SA node so it becomes the pacemaker

41
Q

sinus arrest - what is person’s heart rate

A

40-60 b/c AV node will kick in

42
Q

what is sinus arrest

A

SA node stops working

43
Q

3rd degree block what will HR be

A

15-40 times/min (purknje fibers)

44
Q

PNS originates in

A

medulla

45
Q

vagus nerve is nerve

A

trunk

46
Q

vagus nerve has efferent nerves going to heart and it also has

A

afferent sensory nerves monitoring heart

47
Q

what does it mean that vagus nerve is nerve trunk

A

it has efferent and afferent nerves to heart to monitor and control

48
Q

vagus primarily moderates (PNS)

A

SA and AV node

49
Q

sympathetic nerves primarily innervate

A

SA, AV, and ventricular muscle

50
Q

there is almost no PNS control of

A

muscle itself

51
Q

Parasympathetic releases what

A

ACh

52
Q

what is the kindo f receptor for ACh

A

G protein coupled muscarinic receptor

53
Q

what is affect of parasympathetic onheart

A

inhibitory

54
Q

what is released from postganglionic nerve sympathetic

A

NE

55
Q

NE is a

A

catecholamine

56
Q

catecholamine

A

dopamine, NE, EPI

57
Q

dopamine is converted into

A

NE

58
Q

what is receptor for sympathetic, NE

A

betaadrenergic receptor

59
Q

what nerves increase rate of conraction

A

sympathetic nerves

60
Q

activation of beta receptors inheart does what to SA node

A

increases firing rate, makes them more leaky to sodium and calcium

61
Q

how does beta receptors in heart increase SA node

A

they make them more leaky to sodium and calcium

62
Q

how do muscarinic receptors slow or stop heart rate

A

they open voltage sensitive potassium channels to cause hyperpolarization

63
Q

if sympathetic is high, PNS is

A

low

Physiology I Block 4 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions