Ch. 18- The Heart Flashcards

1
Q

Take blood away from the heart

A

Arteries

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2
Q

Bring blood back to the heart

A

Veins

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3
Q

The smallest blood vessel. Functions in gas exchange and distributing nutrients

A

Capillaries

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4
Q

The region between the pleural sacs; contains the heart and all of the thorax except the lungs

A

Mediastinum

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5
Q

What is the largest blood vessel?

A

Aorta

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6
Q

What layer prevents overfilling of the heart with blood?

A

Fibrous pericardium

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7
Q

What 2 layer membrane contains the pericardial fluid in between?

A

Serous pericardium

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8
Q

What is the role of the pericardial fluid?

A

Allows the heart to beat without friction

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9
Q

Inflammation of tissues around the heart

A

Pericarditis

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10
Q

What is the average heart rate in a person?

A

75 beats/min

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11
Q

What are the three layers of the heart?

A

Epicardium
Myocardium
Endocardium

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12
Q

Prevents backflow into atria during ventricular contraction

A

Atrioventricular valves

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13
Q

Prevents backflow from aorta and pulmonary trunk into the ventricles

A

Semilunar valves

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14
Q

Proteins that pull cell together tightly

A

Desmosomes

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15
Q

Allow ions to pass from one cell to another

A

Gap Junctions

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16
Q

Links one cell to the next via actin myofilaments

A

Mechanical junctions

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17
Q

Oxygen storage molcule

A

Myoglobin

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18
Q

Systole is…

A

Contraction

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19
Q

Diastole…

A

Relaxation

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20
Q

Heart Rate=

A

Systole/Diastole

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21
Q

Normal heartbeat is triggered by what?

A

Sinoatrial node

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22
Q

Normal heartbeat is also referred to by

A

The Sinus Rhythm

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23
Q

How long is the cardiac cycle?

A

0.8 seconds

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24
Q

What is the pacemaker of the heart?

A

Sinoatrial node

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25
Q

True or False.

Myocytes are autorhythmic

A

True

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26
Q

The study of electrical activity of cells is called…

A

Electrophysiology

27
Q

Resting membrane potential is…

A

-60 mVolts

28
Q

Is the RMP stable or unstable?

A

Unstable

29
Q

Rapid up and down voltage shift

A

Action potential

30
Q

Loss of polarity (becomes more +)

A

Depolarization

31
Q

Membrane polarity (-) regained

A

Repolarization

32
Q

What type of cells have unstable resting potentials called pacemaker potentials

A

Autorhythmic cells

33
Q

During the pacemaker potential, what is the value shift of milliVolts?

A

-60 to -40

34
Q

Why does the heart beat every 0.8 seconds?

A

Because the SA node has an unstable pacemaker potential

35
Q

What does the right side of the heart do?

A

It receives oxygen-poor blood from the body tissues and then pumps this blood to the lungs to pick up oxygen and get rid of carbon dioxide

36
Q

What does the left side of the heart do?

A

It receives the oxygenated blood returning from the lungs and then pumps this blood throughout the body to supply oxygen and nutrients to body tissues

37
Q

The right side of the heart participates in what circuit?

A

Pulmonary circuit

38
Q

The left side of the heart participates in what circuit?

A

Systemic circuit

39
Q

Through what 3 veins does blood enter the right atrium?

A

Superior vena cava, inferior vena cava, coronary sinus

40
Q

What is the role of the atrioventricular valves (AV)?

A

Prevent back flow into the atria when the ventricles contract

40
Q

What is the role of chordae tendineae and where do they attach?

A

They attach to each AV valve flap and they anchor the cusps to the papillary muscles protruding from the ventricular walls

41
Q

What kind of cell junctions does cardiac muscle contain (specifically intercalated discs)?

A

Desmosomes and gap junctions

42
Q

Cardiac pacemaker cells are a part of the intrinsic conduction system and have what kind of testing potential?

A

Unstable

43
Q

Spontaneously changing membrane potentials in the heart

A

Pacemaker potentials

44
Q

At what membrane potential does the Ca2+ channels open?

A

-40mV

45
Q

What happens at the AV node?

A

The impulse is delayed about 0.1 seconds before moving through the rest of the system

46
Q

What is the only electrical connection between the atria and ventricles?

A

AV bundle (bundle of His)

47
Q

What is an arrhythmia?

A

Irregular heart rhythms

48
Q

A condition of rapid and irregular or out of phase contractions in which control of heart rhythm is taken away from the SA node by rapid activity in other heart regions

A

Fibrillation

49
Q

Cardiac output is…

A

The amount of blood pumped out by each ventricle in 1 min

50
Q

Cardiac output equals

A

HR X SV

51
Q

Stroke volume equals…

A

End diastolic volume (EDV) - End systolic volume (ESV)

52
Q

How much does each ventricle pump out per heartbeat?

A

70 ml

53
Q

The degree to which cardiac muscles are stretched before they contract

A

Preload

54
Q

What is the stroke volume amount?

A

70 ml/beat

55
Q

Cardiac output is approximately…

A

5.25 L/min

56
Q

What nerve secretes acetylcholine to slow SA node firing and regulate heart beat?

A

Vagal nerve

57
Q

During sympathetic stimulation the heart beats…

A

Faster

58
Q

What is normal blood pressure?

A

115-120/70-80 mmHg

59
Q

Does thyroxine increase or decrease HR?

A

Increase

60
Q

Left side failure of the heart results in

A

Pulmonary edema

61
Q

Right side failure of the heart results in

A

Peripheral congestion

62
Q

Occurs when blood supply to tissue is deficient

A

Ischemia

63
Q

What does the foramen ovale do in a fetus?

A

Shunts blood from right to left atrium