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lecture > Chapter 18: Heart > Flashcards

Chapter 18: Heart Flashcards

1
Q

What are chordae tendinae?

A

the strings attached to the heart valves that keep the valve from reversing (heart strings)

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2
Q

What is the foramen ovale botalli?

A

An inter-atrial opening to bypass the lungs in a fetus (because the lungs are filled with liquid)

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3
Q

When does the foramen ovali botalli close?

A

when the baby is born

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4
Q

What is the bypass between the pulmonary artery and aorta called?

A

ductus arteriosus

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5
Q

What does the ductus venosus do?

A

it is an umbilical vein that brings blood to the vena cava (in a fetus)

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6
Q

The heart pumps blood to the rest of the body, but the heart also needs its own blood supply which is provided by _______ via the ________

A

Coronary arteries via the right atrium

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7
Q

What are the three layers of the heart wall?

A

epicardium, myocardium, and endocardium

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8
Q

Define epicardium:

A

the outermost layer, the visceral layer (space without friction)

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9
Q

Define myocardium:

A

muscle of the heart, cardiac muscle

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10
Q

Define endocardium:

A

white sheet of endothelium resting on CT layer, it lines the inside of the heart wall

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11
Q

Plasma membrane of cardiac cells interlock via __________.

A

intercalated discs

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12
Q

Intercalated discs contain anchoring __________ and ______.

A

desmosomes and gap junctions

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13
Q

The atria and ventricle cells are _______ by gap junctions because ___________________________.

A

not connected, if they were, the whole heart would contract at the same time and blood wouldn’t flow through properly (atria cells are connected to other atria cells via gap junctions, but atria cells are not connected to ventricle cells by gap junctions)

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14
Q

_______ are what hold the intercalated discs together during contraction.

A

desmosomes

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15
Q

Syncytial:

A

one cell depolarizes, the signal gets transmitted to others

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16
Q

Where is the calcium (used in a cardiac action potential) stored?

A

the sarcoplasmic reticulum

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17
Q

What happens in stage 0 of the cardiac action potential?

A

cell is at -90mV, depolarizes, Na opens and goes inside (to make more positive)

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18
Q

What happens in stage 1 of the cardiac action potential?

A

~35+, Na closes, K opens, K goes out (more positive)

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19
Q

What happens in stage 2 of cardiac action potential?

A

Ca is released (plateau)

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20
Q

What happens in stage 3 of cardiac action potential?

A

Ca closes

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21
Q

What happens in stage 4 of cardiac action potential?

A

K closes

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22
Q

You could simplify the stages of a cardiac action potential to three stages: ________, __________, and _________

A
  1. Depolarization (due to Na influx) 2. Plateau phase (due to Ca influx, few K channels open) 3. Repolarization (Ca channels close, K opens until -90mV is reached)
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23
Q

How long does a cardiac action potential take?

A

~200 milliseconds

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24
Q

The plateau phase makes the cardiac action potential _________ than a skeletal action potential because ______________________________________.

A

longer, because this extends the absolute refractory period so the heart has time to rest so tetanus won’t occur (no matter how fast or slow the heart is beating)

25
Q

What is tetanus?

A

when your muscle (skeletal) action potential occurs to fast and too often, which results in your muscle to stop working (overuse causes the muscle to stop working for a short period of time)

26
Q

What do pacemaker cells do?

A

get the cardiac muscles to contract

27
Q

Autorhythmic cells are ____________ that start their own __________ and do not need __________

A

special cardiac cells, action potential, a stimulus

28
Q

What is the resting membrane potential and the threshold of an autorhythmic cell?

A

rmp= -60 threshold= -40

29
Q

Describe the stages of the action potential of autorhythmic cells (Figure 18.13 in book)

A

1) Autorhythmic cells has a lot of leaky Na channels which raise the mV to its -40 threshold 2) Voltage gated Ca channel opens and depolarizes cell 3) Ca closes, K opens (more -) to rmp-60 (then back up due to leaky Na channels)

30
Q

What does the sinoatrial node (SA) do?

A

sets the pace for the heart because no other region of the conduction system or myocardium has a faster depolarization rate (the heart’s pacemaker)

31
Q

What is the bundle of His?

A

(aka atrioventicular bundle) fibers that conduct impulses from the AV node to the right and left ventricles -septum between right and left ventricles

32
Q

What are Purkinje fibers?

A

depolarize the contractile cells of both ventricles (located on the outer walls of the ventricles)

33
Q

What 3 reasons does the cardiac conduction system works the way it does?

A
  1. atria and ventricular cells are not connected by gap junctions (so the heart doesn’t contract at the same time) 2. Action potential is delayed in the AV node (so that the atria contracts first) 3. Ventricle contracts form the bottom up
34
Q

The ____________ nervous system decreases heart rate and inhibits the SA node by releasing _____________ via the _____ nerve.

A

parasympathetic NS, Ach, vagus

35
Q

The ______________ nervous system increases heart rate by releasing ___________.

A

sympathetic NS, Epinephrine and Noepinephrine (direct innervation)

36
Q

What is arteriole pressure?

A

blood pressure not in the heart (elsewhere in the body)

37
Q

When ventricles contract it is referred to as ___________

A

systolic (blood to arteries), in blood pressure this is the top number (120)

38
Q

When the atria contracts it is referred to as _____________

A

diastolic (blood to ventricles), in blood pressure this is the bottom number (80)

39
Q

Cardiac Output=

A

volume of blood leaving the heart per minute

40
Q

What is the equation for cardiac output?

A

stroke volume times rate

41
Q

Stroke volume and cardiac output are ________________

A

directly proportional

42
Q

What is the Frank Starling Law?

A

more blood into the heart, the more blood pumps out of the heart

43
Q

If finger blood vessels dilate, blood pressure would _________ and resistance would _________

A

decrease, decrease (Ach dilates vessels)

44
Q

Epinephrine and noepinephrine _________ vessels increases blood pressure and ________ resistance

A

constricts, increases

45
Q

When you have heat stroke, your resistance is low and your blood pressure is low. How could you fix this?

A

By drinking water or eating salty good, this would increase blood volume, which would increase blood pressure and resistance

46
Q

Diastole is blood flowing from the _____________ to _____________

A

atria to ventricle

47
Q

Systolic is blood flowing from the _____________ to _____________

A

ventricles to the body

48
Q

Which is longer between sounds (“lub dub”), diastole or systole?

A

diastole

49
Q

How are cardiac action potentials different from other action potentials in the body?

A

cardiac aps have a plateau phase

50
Q

Pacemaker cells are _____________cells, NOT _____________ cells

A

cardiac cells, not neural

51
Q

What is the purpose of gap junctions in heart cells?

A

so that the action potential can travel through the heart

52
Q

What is the function of Purkinje fibers in the cardiac conduction system?

A

they bring the action potential down into the ventricles

53
Q

Blood pressure is a measure of _____________ pressure

A

arteriole (not in the heart)

54
Q

Systolic is the _____________ contracting

A

ventricles

55
Q

Diastolic is the when the _____________ contracts

A

atria

56
Q

What is this graph?

A

A normal ECG reading

57
Q

The P wave (P to Q) corresponds to _____________

A

atrial depolarization and contrats

58
Q

The QRS indicates _____________

A

ventricular depolarization and ventricular contraction

59
Q

The S to T segment indicates _____________

A

ventricular repolarization

lecture (17 decks)

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