The Cardiovascular System 3: Anatomy of the Heart Part 2 Flashcards

1
Q

What is the primary function of heart valves?

A

To act as one-way valves that ensure the unidirectional flow of blood between the atria and ventricles, and subsequently out of the heart.

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2
Q

Name the 2 atrioventricular (AV) valves.

A

Left AV valve (bicuspid/mitral)
Right AV valve (tricuspid)

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3
Q

How many cusps do the 2 atrioventricular (AV) valves have?

A

Left AV valve (bicuspid/mitral) has 2 cusps.

Right AV valve (tricuspid) has 3 cusps.

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4
Q

Name the 2 semilunar (SV) valves.

A

Pulmonary valve
Aortic valve

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5
Q

How many cusps do the 2 semilunar (SV) valves have?

A

Both the pulmonary and aortic valves have 3 cusps.

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6
Q

Which valve is located between the right atrium and right ventricle?

A

The tricuspid valve (right AV valve).

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7
Q

Which valve is located between the left atrium and left ventricle?

A

The mitral (bicuspid) valve (left AV valve).

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8
Q

Name the cusps of the pulmonary valve.

A

Left cusp
Right cusp
Anterior cusp

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9
Q

Name the cusps of the aortic valve.

A

Left cusp
Right cusp
Posterior cusp

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10
Q

What are the cusps of the tricuspid (right AV) valve?

A

Anterior cusp
Posterior cusp
Septal cusp

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11
Q

What are the cusps of the mitral (bicuspid) valve?

A

Anterior cusp
Posterior cusp

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12
Q
A
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13
Q
A
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14
Q

What is the primary function of atrioventricular (AV) valves?

A

To guard the AV orifices and ensure unidirectional blood flow from the atria to the ventricles.

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15
Q

How are the cusps of the AV valves connected to the ventricular surface?

A

The cusps are attached to the ventricular surface via the chordae tendineae.

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16
Q

What happens to the papillary muscles during ventricular contraction?

A

They contract, tensing the chordae tendineae and drawing the cusps together.

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17
Q

What role do the chordae tendineae play during ventricular contraction?

A

They pull on the cusps to prevent prolapse as ventricular pressure increases.

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18
Q

What is the primary function of semilunar (SL) valves?

A

To ensure unidirectional blood flow from the ventricles to the pulmonary trunk or ascending aorta.

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19
Q

What is the shape of semilunar valve cusps?

A

The cusps are concave superiorly.

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20
Q

How do semilunar valves prevent backflow of blood?

A

The cusps snap shut to catch any backflow of blood toward the heart.

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21
Q

What heart sound is associated with ventricular systole, and what causes it?

A

The first heart sound (“lub”), caused by the closure of the atrioventricular (AV) valves.

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22
Q

During ventricular systole, what role do the chordae tendineae play?

A

The chordae tendineae tighten to hold the AV valve cusps in place and prevent prolapse into the atria.

Papillary muscles contract to pull on the chordae tendineae, securing the AV valves.

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23
Q

During ventricular diastole, what happens to the ventricular myocardium?

A

The ventricular myocardium relaxes, allowing blood to fill the ventricles.

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24
Q

During ventricular distole, what role do the chordae tendineae play?

A

The chordae tendineae remain relaxed as the AV valves open, allowing blood to flow from the atria into the ventricles.

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25
Q

What heart sound is associated with ventricular diastole, and what causes it?

A

The second heart sound (“dub”), caused by the closure of the semilunar valves.

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26
Q

What is a heart murmur?

A

A heart murmur is a sound produced by turbulent blood flow, often resulting from valvular diseases.

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27
Q

Which valves are associated with turbulent blood flow when affected by valvular diseases?

A

Both the atrioventricular (e.g., mitral or tricuspid) and semilunar (e.g., aortic or pulmonary) valves can be involved.

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28
Q

What is a prolapsed mitral valve (MV)?

A

A prolapsed mitral valve occurs when the mitral valve does not close properly and bulges back into the left atrium during ventricular systole.

It can lead to backflow of blood from the left ventricle into the left atrium.

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29
Q

Where is the auscultation area for the bicuspid (mitral) valve?

A

5th left intercostal space, midclavicular line.

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30
Q

Where is the auscultation area for the tricuspid valve?

A

5th left or right intercostal space, near the sternal border (commonly also at the 4th left intercostal space).

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31
Q

Where is the auscultation area for the aortic valve?

A

2nd right intercostal space, near the sternal border.

32
Q

Where is the auscultation area for the pulmonary valve?

A

2nd left intercostal space, near the sternal border.

33
Q

Are auscultation areas the same as the anatomical positions of valves?

A

No, auscultation areas are different from the anatomical positions and are spaced widely apart for clarity of heart sounds.

34
Q

Why are auscultation areas positioned widely apart?

A

To ensure heart sounds from different valves are clearly distinguishable.

35
Q

What occurs at the beginning of diastole?

A

The aortic and pulmonary valves close to prevent backflow of blood into the ventricles.

36
Q

What happens to the atrioventricular (AV) valves during early diastole?

A

The AV valves (tricuspid and mitral) open, allowing blood to flow from the atria into the ventricles.

37
Q

What occurs during atrial contraction in the final moments of diastole?

A

The atria contract to push the remaining blood into the ventricles, completing ventricular filling.

38
Q

What happens to the AV valves as systole begins?

A

The AV valves (tricuspid and mitral) close to prevent backflow of blood into the atria.

39
Q

What happens during ventricular systole?

A

The aortic and pulmonary valves open, allowing blood to flow from the ventricles into the aorta and pulmonary artery.

40
Q

the contractions of the right and left chambers of the heart are …

A

synchronous - occur at the same time, followed by simultaneous left and right ventricular contractions.

41
Q

What is the function of the conducting system in the heart?

A

To generate and transmit impulses that produce coordinated contractions of the heart chambers.

42
Q

Where is the sino-atrial (SA) node located?

A

At the junction of the superior vena cava (SVC) and right atrium, near the superior end of the sulcus terminalis.

43
Q

Why is the SA node called the “pacemaker of the heart”?

A

It initiates impulses at a rate of approximately 70 beats per minute, regulating the heart’s rhythm.

44
Q

Which artery supplies the SA node?

A

The sino-atrial nodal artery.

45
Q

How is the activity of the SA node regulated?

A

Stimulated by the sympathetic nervous system to increase heart rate.

Inhibited by the parasympathetic nervous system to decrease heart rate

46
Q

What is the sulcus terminalis?

A

A groove on the right atrium where the SA node is located.

47
Q

Where is the atrioventricular (AV) node located?

A

It is located in the posterior inferior region of the interatrial septum near the opening of the coronary sinus.

48
Q

What is the role of the AV node in cardiac contraction?

A

The AV node delays impulse conduction to the ventricles, allowing the atria to fully relax before ventricular contraction.

49
Q

How many impulses per minute can the AV node generate on its own?

A

Roughly 50 impulses per minute.

50
Q

What supplies blood to the AV node?

A

The AV nodal artery.

51
Q

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

A

The AV bundle conducts impulses from the AV node to the ventricles.

52
Q

Where does the AV bundle divide into branches?

A

It divides into right and left bundle branches in the interventricular septum (IVS).

53
Q

What do the branches of the AV bundle supply?

A

They supply the muscles of the interventricular septum (IVS), the papillary muscles, and the walls of the ventricles.

54
Q

In which part of the heart is the interventricular septum (IVS) located?

A

The IVS is located between the right and left ventricles.

55
Q

What forms the cardiac plexus?

A

The cardiac plexus is formed by both sympathetic and parasympathetic fibers (visceral efferent fibers) and visceral afferent fibers.

56
Q

What is the role of visceral afferent fibers in the cardiac plexus?

A

They conduct nociceptive (pain) information from the heart.

57
Q
A

black circle = Autonomic fibres from the cardiac plexus

58
Q

Where are the cell bodies of the sympathetic preganglionic fibers to the heart located?

A

In the lateral horn of gray matter of the superior 4-5 thoracic spinal cord segments.

59
Q

Where do the sympathetic preganglionic fibers synapse?

A

In the cervical and superior thoracic paravertebral ganglia of the sympathetic chains (trunks).

60
Q

What is the pathway of the postganglionic sympathetic fibers?

A

They continue via the cardiopulmonary splanchnic nerves (cardiac nerves) to the cardiac plexus.

61
Q

Where are the cell bodies of the parasympathetic preganglionic fibers to the heart located?

A

In the nuclei of the vagus nerve in the brainstem.

62
Q

Where do the parasympathetic preganglionic fibers synapse?

A

In intrinsic ganglia found near the SA node, AV node, and atrial wall.

63
Q
A
64
Q

What nerve carries parasympathetic fibers from brainstem to the cardiac plexus?

A

The vagus nerve.

65
Q

Which spinal cord segments contribute sympathetic fibers to the cardiac plexus?

A

C8, T1, T2, T3, T4, and T5.

66
Q

Where do the sympathetic fibers synapse before reaching the cardiac plexus?

A

In the paravertebral ganglia of the sympathetic chain.

67
Q

How do sympathetic fibers reach the cardiac plexus?

A

Via cardiac nerves from the paravertebral ganglia.

68
Q

How does the heart sense pain?

A

The heart is sensitive to pain (e.g., from ischemia) via visceral afferent fibers that originate in the heart and return to the spinal cord segments T1-T4/5 through cardiac and spinal nerves.

69
Q

What is cardiac referred pain?

A

Cardiac referred pain is a phenomenon where heart pain is perceived as originating from a superficial area of the body, such as the skin, instead of the heart.

70
Q

Which spinal segments are involved in cardiac referred pain?

A

T1-T4/5 spinal nerves, as determined by the dermatome map.

71
Q

Why does referred pain occur?

A

It occurs because visceral afferent fibers and somatic afferent fibers share the same spinal nerves and dorsal roots as they return to the spinal cord.

72
Q

Which spinal cord segments are involved in cardiac referred pain?

A

C8, T1, T2, T3, T4, and T5.

73
Q

Through which pathway do visceral afferent fibers from the heart travel to the spinal cord?

A

Via cardiac nerves, through the cardiac plexus, and to the paravertebral ganglia of the sympathetic chain.

74
Q

What is the destination of the visceral afferent fibers that cause referred pain?

A

They share pathways with somatic afferent fibers and project pain signals to the skin.

75
Q

What structure contains the cell bodies of sensory neurons involved in cardiac referred pain?

A

The dorsal root ganglion.