The Heart Flashcards

1
Q

What body cavity is the heart in?

A

The mediastinum

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

Where do the base and apex of the heart point?

A

The base points towards the right shoulder and the apex points towards the lower left abdomen.

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

What are the three layers of the heart?

A

The pericardium, the myocardium, and the endocardium.

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

What is the pericardium of the heart made of?

A

It is a double walled fibrous sac

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

What are the layers of the pericardium? What are their functions?

A

Outermost layer: Fibrous pericardium is the thickest layer of the pericardium and protects and anchors the heart as well as prevents overfilling

The inner layer is the serous pericardium and is composed of a parietal layer outside of a visceral or epicardium layer outside of a fluid filled pericardial cavity.

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

What layer of the heart is the muscle located in?

A

The myocardium.

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

What are the cardiac muscles wrapped in?

A

Connective tissue wrappings

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

What are the three functions of cardiac connective tissue wrappings?

A
  1. They reinforce myocardium internally and anchor the muscle fibers
  2. It provides support for vessels and valves
  3. It directs the spread of actions potentials across the heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the composition of the endocardium?

A

it is a layer of endothelium and connective tissue on the inner myocardial surface and is continuous with vessels

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

What are the two sulci on the heart?

A

The coronary sulcus or atrioventricular groove, and the anterior/posterior interventricular sulcus

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

What are the three sources of oxygen poor blood into the right atrium?

A
  1. The superior vena cava (above the heart)
  2. The inferior vena cava (below the heart)
  3. The coronary sinus (wall of the blood itself in the coronary sulcus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 4 veins that carry oxygenated blood?

A

pulmonary veins

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

What are the small muscles called primarily found in the right atrium?

A

Pectinate muscles

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

What is the opening between the left and right atrium found in babies called?

A

The foramen ovale

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

What does the closed foramen ovale become?

A

the fossa ovalis.

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

What blood vessel does the right ventricle send blood out of?

A

The pulmonary trunk

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

What blood vessel takes blood from the left ventricle to the body?

A

The aorta

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

What are the two types of muscle found in the ventricles? What is the differentiating characteristic?

A

Trabeculae carneae
Papillary muscles link the chordae tendineae

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

What are the two classifications of heart valves?

A

There are two atrioventricular valves and two semilunar valves

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

What are the names of the atrioventricular valves?

A

The right one is called the tricuspid valve and the left is called the mitral or bicuspid valve.

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

What are the two semilunar valves called?

A

The valve exiting the right ventricle is the pulmonary valve, and the valve exiting the left ventricle is the aortic valve.

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

What are the two types of valve problems?

A

Valvular insufficiency is the valves not closing all the way, and stenosis is the stiffening of the valves due to calcification or scar tissue

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

What has more resistance? The pulmonary blood circuit or the systemic one?

A

The systemic circuit has 5x the resistance.

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

Which ventricle has thicker walls? By how much?

A

The left ventricle is 3X thicker.

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

Where do the left and right coronary arteries come from? Where are they located?

A

They come from the base of the aorta and wrap around the coronary sulcus.

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

What does the left coronary artery branch into?

A

The circumflex artery (around the back) and the anterior interventricular artery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What branches off from the right coronary artery?

A

The right marginal artery anteriorly, and posteriorly the posterior interventricular artery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is important about the coronary arteries come from the base of the aorta?

A

They deliver blood when it is relaxed. When the ventricles are contracting, they constrict the coronary arteries.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are anastomoses in the heart?

A

They are direct linking of arteries and are important for providing alternative pathways for blood flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does angina pectoris mean?

A

Chest pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is a myocardial infarction?

A

A heart attack is a complete blockage and no blood moving to an area of the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What four cardiac veins feed into the coronary sinus?

A

The great cardiac vein (left)
Middle cardiac vein (posterior)
The small cardiac vein (lower right)
The anterior cardiac veins (upper right)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the biggest difference between skeletal and cardiac muscle cells?

A

Cardiac muscle has intercalated discs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the two types of junctions in intercalated discs?

A

Gap junctions for electrical coupling
desmosomes for strong cell to cell adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the phenomenon that gap junctions allow for?

A

functional syncytium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the two types of cardiac muscle?

A

contractile and autorythmic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What percentage of cardiac muscle cells are pacemakers?

A

roughly 1 percent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Is the ECF considered a fast or slow channel?

A

Slow channel

39
Q

What is the duration of the absolute refractory period of a cardiac muscle vs skeletal? Why?

A

It is roughly 250ms vs 1-2 ms so the muscle doesn’t go titinic

40
Q

Why do circulatory blockages matter more in the heart?

A

Respiration is purely aerobic

41
Q

What is the depolarization phase of a heartbeat driven by?

A

voltage gated Na+ channels

42
Q

Why is the plateau of a heartbeat longer?

A

The calcium influxes at the same rate as potassium goes out.

43
Q

What happens in the repolarization phase?

A

The potassium channels open and the calcium channels close.

44
Q

What is sinus rhythm

A

The spontaneous depolarization of the SA node.

45
Q

Where is the SA node found?

A

The right atrium

46
Q

What are autorhythmic cardiac muscle cells?

A

cells that are able to spontaneously depolarize

47
Q

What is special about the structure of cardiac muscle cells?

A

They are unstable because funny sodium channels open at negative membrane potentials plus slow closing potassium channels

48
Q

What is special about action potentials in autorhythmic cells?

A

They are caused by calcium channels, not sodium channels.

49
Q

What is the order of the intrinsic conduction system of the heart?

A
  1. SA node
    2.AV node
  2. AV bundle
  3. Left and right bundle branches
  4. Subendocardial conducting network/Purkinje fibers
50
Q

Why is the SA node considered the pacemaker?

A

It spontaneously depolarizes the most.

51
Q

Where is the bottleneck in the intrinsic conduction system of the heart?

A

From the atria to the ventricles

52
Q

What is brachychardia?

A

Slower than normal HR (<55BPM)

53
Q

What is tachycardia?

A

Faster than normal HR (>100BPM)

54
Q

What has a dampening effect on HR under resting conditions?

A

tonic parasympathetic output

55
Q

What does an ECG tracing record?

A

The electrical tracing of the heart

56
Q

What does a P wave represent?

A

Atrial depolarization

57
Q

What follows a P wave?

A

A QRS complex (ventricular depolarization)

58
Q

What follows a QRS complex?

A

A T wave (ventricular repolarization)

59
Q

Where on an ECG do we see atrial repolarization?

A

The QRS complex

60
Q

What happens if the SA node is nonfunctional? (junctional rhythm)

A

The AV node takes over

61
Q

What is ventricular fibrilation?

A

What is happening in the ventricles is not being controlled by the intrinsic conduction system

62
Q

What are the stages of the cardiac cycle?

A

Systole (contraction blood OUT) and Diastole (filling with blood)

Atrial systole and diastole -> ventricular systole and diastole

63
Q

What is the first phase of the cardiac cycle?

A

The period of ventricular filling, mid to late diastole. The AV vales are open and the SL valves are closed

64
Q

What happens when ventricles reach 70% capacity?

A

There is atrial systole to fill the rest of the ventricles, and the AV valves begin to close. The atria begin diastole

65
Q

What is EDV?

A

End diastolic volume is the filled volume of the ventricles

66
Q

What is the second stage of the cardiac cycle?

A

The ventricular systole.

67
Q

Describe the cardiac events that lead to the QRS complex and T wave.

A

The ventricles begin to contract, the AV valves close, there is a period of isovolumetric contraction, and that pressure opens the SL valves for the ventricular ejection (systole) phase.

68
Q

Describe the cardiac events of the isovolumetric relaxation phase

A

There is an early diastole which decreases pressure in the ventricles, which closes the SL valves

69
Q

What is the timing breakdown of a cardiac cycle?

A

0.1 sec of atrial systole, 0.3 seconds of ventricular systole, and then 0.4 seconds of quiescent period (atrioventricular diastole)

70
Q

What determines the direction of blood in the heart?

A

Pressure changes open and close the valves

71
Q

What is the blip in pressure caused by the recoil of the aorta called?

A

The dicrotic notch

72
Q

Where is the Stroke volume found?

A

It is the volume pushed out from each ventricle

73
Q

What is the ESV?

A

The end systolic volume is the volume of blood left over after systole

74
Q

What are the two heart sounds?

A

The first is caused by the closing of the AV valves at the beginning of ventricular systole
The second is the closing of the SL valves at the end of systole

75
Q

What are two reasons for abnormal heartbeat sounds (Heart murmurs)?

A

Valvular stenosis: Valve doesn’t open very well, and higher pitch of sounds when blood is being pushed through
Valvular insufficiency: Leakage of blood back instead of silence

76
Q

What is CO?

A

Cardiac output is the amount of blood pumped by the heart for each ventricle per minute

77
Q

What is the calculation of CO?

A

It is stroke volume*HR

78
Q

What is the average CO for a healthy male?

A

5L/min

79
Q

What is the calculation for SV?

A

Stroke volume is end diastolic volume - end systolic volume

80
Q

How does exercise affect CO?

A

It increases 4-5 times in well trained people, and 7 times in marathon runners

81
Q

What is the notion of cardiac reserve?

A

There is a heart capacity to pump more

82
Q

What are 4 determinants of HR?

A
  1. autonomic fibers of the SA node
  2. circulating hormones
  3. Plasma electrolyte concentrations
  4. Body temperature
83
Q

What NT kicks in with the parasympathetic nervous system?

A

Acetylcholine decreases spontaneous depolarization

84
Q

What is the term for the dominant effect of the parasympathetic NS on the heart in resting conditions?

A

Vagal tone

85
Q

What is the Frank Starling Law of the heart?

A

Within defined limits, the heart will pump as much blood as it receives

86
Q

At what stretch is cardiac muscle at rest compared to optimal length?

A

It is shorter than the optimal length

87
Q

Define preload

A

The amount of blood entering the heart that is expected to leave

88
Q

What is afterload?

A

The pressure that ventricles have to overcome to open the semilunar valves. It is the pressure of the aorta/pulmonary trunk

89
Q

How does hypertension affect the heart?

A

It increases the afterload, therefore the heart has a lower end systolic volume and therefore a decreased SV

90
Q

What are extrinsic influences on stroke volume?

A

factors outside the heart that change the vigor of contraction without changing the EDV

91
Q

What leads to a stronger contractile reflex?

A

An increase in Ca++ influx

92
Q

What are two reasons for the Ca++ influx leading to a stronger heart contraction?

A
  1. Sympathetic stimulation increases the strength of contraction as well as rate of contraction
  2. Drugs such as digoxin increase contractility
93
Q
A