Exam 1: 30 Jan 25 Anatomy and Function of the Pericardium and Valves Flashcards

(108 cards)

1
Q

What are the three layers of the pericardium?

A
  • Visceral pericardium
  • Serous pericardium
  • Fibrous pericardium

The visceral pericardium is a thin, transparent membrane covering the heart. The serous pericardium consists of a parietal layer glued to the fibrous pericardium, which is the tough outer layer.

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2
Q

What is the function of the fibrous pericardium?

A

It serves as a tough outer layer that is less compliant and helps protect the heart.

The fibrous pericardium is the most rigid layer attached to the heart.

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3
Q

What role do gap junctions play in the heart?

A

They allow electrical signals to move between heart muscle cells via the flow of ions, particularly sodium and calcium.

Sodium is crucial for conducting electrical potentials from one cell to another.

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4
Q

How are the muscle fibers in the ventricles arranged?

A

They are arranged in two thick layers oriented at perpendicular angles.

This crisscrossing pattern allows efficient pumping of blood.

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5
Q

What analogy is used to explain how the ventricles pump blood?

A

Squeezing a wet towel with opposite hands.

This demonstrates the efficient way the ventricles can push blood into a high-pressure system.

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6
Q

What are the components of heart valves known as?

A

Cusps or leaflets.

The AV valves consist of these cusps attached to the ventricles via chordae tendineae.

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7
Q

What is the role of chordae tendineae?

A

They attach the cusps of the AV valves to the papillary muscles.

Chordae tendineae function like tendons for the heart.

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8
Q

What is the significance of coronary perfusion during diastole?

A

More blood flow occurs during diastole due to lower pressures in the heart walls.

This is crucial for the heart’s oxygen supply.

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9
Q

What is the impact of aortic pressure on coronary blood flow?

A

Aortic pressure drives coronary blood flow.

Higher heart rates can reduce the time for coronary perfusion.

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10
Q

True or False: The right heart’s output is significantly affected during inspiration.

A

False

The right heart’s thicker atrial walls help withstand negative pressure better.

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11
Q

What happens to cardiac output during early inspiration?

A

It drops due to reduced preload and unchanged afterload for the left heart.

The initial drop is followed by an eventual increase as the chest fills with blood.

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12
Q

What is the central venous pressure (CVP) waveform?

A

It includes components like the a wave, C wave, V wave, X descent, and Y descent.

Understanding the CVP waveform is important for diagnosing heart conditions.

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13
Q

What effect does negative thoracic pressure have on venous pressure?

A

It reduces venous pressure by pulling on the walls of the veins.

This can lead to a temporary drop in cardiac output.

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14
Q

What is the mean central blood pressure (CBP) indicative of?

A

It indicates either poor health or a measurement taken far from the heart.

The mean CBP is about 15.

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15
Q

How does negative thoracic pressure affect the left heart’s preload?

A

It reduces preload, leading to a significant drop in cardiac output.

The left heart is more affected than the right heart during inspiration.

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16
Q

What is the relationship between pulmonary arterial pressure and thoracic pressure?

A

Reduced thoracic pressure decreases pressures in pulmonary arteries and veins.

This further reduces preload for the left heart.

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17
Q

What happens to cardiac output after the initial drop during inspiration?

A

It eventually increases as the chest fills with blood.

This process aids heart function over time.

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18
Q

What are the cusps of the AV valves attached to inside the ventricles?

A

Chorda tendineae

Chorda tendineae are connective tissues that function like tendons for the heart.

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19
Q

What role do papillary muscles play in heart function?

A

Reinforce AV valves to prevent backflow into the atria

Papillary muscles contract along with the ventricular muscle fibers during ventricular contraction.

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20
Q

What is the typical ejection fraction for a healthy heart?

A

Approximately 70 mL ejected from a starting volume of 120 mL

This fraction is a measure of the heart’s efficiency in pumping blood.

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21
Q

How many cusps does the tricuspid valve have?

A

Three cusps

The cusps are named anterior, posterior, and septal.

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22
Q

What is the primary purpose of the AV valves?

A

Prevent backflow of blood into the atria during ventricular contraction

Proper functioning of these valves is crucial for maintaining efficient blood flow.

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23
Q

What happens to the heart valves during high pressure in the ventricles?

A

They are reinforced by papillary muscles to prevent being blown into the atria

This reinforcement is critical during ventricular ejection.

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24
Q

What is the structure of the left AV valve called?

A

Bicuspid valve

It consists of two cusps: anterior and posterior.

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25
What can happen if the papillary muscles are damaged?
It can lead to valve problems due to improper function ## Footnote This may initially manifest as a pumping problem before evolving into valve dysfunction.
26
What are the names of the three cusps of the aortic valve?
Left cusp, right cusp, posterior cusp ## Footnote These cusps are crucial for proper valve function and coronary artery perfusion.
27
What is the consequence of valve calcification or cholesterol buildup?
Reduced opening and potential backflow of blood ## Footnote This can lead to conditions like aortic stenosis.
28
True or False: The pulmonary valve has three cusps.
True ## Footnote The cusps are named left, right, and anterior.
29
What keeps the electrical activity of the atria separate from the ventricles?
Cartilaginous insulation ## Footnote This insulation prevents electrical conduction between the two sections of the heart.
30
What happens to the aorta during diastole?
It recoils to help push blood forward ## Footnote This recoil can also retrograde blood flow which aids in coronary perfusion.
31
Fill in the blank: The left coronary artery receives blood flow through the _______.
Aortic valve ## Footnote The left coronary artery opening is located at the left cusp of the aortic valve.
32
What can happen if the valves do not fit together properly?
Leaky valves that allow backflow of blood ## Footnote This can lead to improper filling of heart chambers.
33
What is the significance of the coronary arteries' opening location?
They are embedded in the cusps of the aortic valve ## Footnote This design allows for effective perfusion during diastole.
34
What separates the electrical activity of the top and bottom of the heart?
A cartilaginous ring ## Footnote This ring keeps the atria and ventricles insulated from each other.
35
What is the function of the bundle of His in the heart?
To conduct action potentials from the atria to the ventricles ## Footnote It has a small opening in the cartilaginous ring that allows this conduction.
36
What are the two main branches of the left coronary artery?
* Anterior descending artery (LED) * Circumflex artery
37
What does the right coronary artery typically supply blood to?
The posterior descending artery (PDA) ## Footnote In most individuals, the PDA is a branch of the right coronary artery.
38
What is the name of the large vein situated on the posterior inferior part of the heart?
Great cardiac vein
39
What is the coronary sinus?
The end of the great cardiac vein that empties into the right atrium
40
How much coronary blood flow is typically needed for each 100 grams of heart muscle?
70 mL
41
What is the average coronary blood flow required for the heart per minute?
225 mL
42
During which phase of the cardiac cycle does most coronary blood flow occur?
Diastole
43
What are the two types of blood vessels in the heart based on their location?
* Epicardial vessels (superficial) * Endocardial/subendocardial vessels (deep)
44
True or False: The left coronary artery provides blood to the high-pressure side of the heart.
True
45
What happens to coronary perfusion during systole?
It decreases significantly due to high pressure in the heart walls.
46
What is retrograde coronary perfusion?
Blood flow moving in the opposite direction, from the heart walls back into the coronary arteries
47
Fill in the blank: The _______ artery runs down the front middle of the heart.
Anterior descending
48
What is the main role of papillary muscles in the heart?
To prevent valves from being blown back into the atria during ventricular contraction
49
What are the three cusps of the right ventricle connected to?
Three sets of papillary muscles
50
What is the primary function of coronary arteries?
To supply oxygenated blood to the heart muscle
51
What is the primary function of coronary veins?
To drain deoxygenated blood from the heart muscle
52
What does a typical left coronary blood flow tracing indicate?
It is not continuous throughout the cardiac cycle and may go negative at times.
53
What does the right coronary artery typically supply blood to during the cardiac cycle?
It provides a more continuous blood flow throughout the cardiac cycle.
54
What happens when coronary blood vessels are squeezed by the heart's contraction?
Blood is pushed both forward and backward ## Footnote Blood vessels can become full in the left ventricular wall, leading to reverse blood flow.
55
What determines coronary blood flow?
The flow is dependent on a pressure gradient ## Footnote The starting pressure driving coronary blood flow is aortic pressure.
56
What is the relationship between aortic pressure and coronary perfusion?
High aortic pressure allows for more perfusion; low aortic pressure makes perfusion difficult.
57
What are the two components of the delta P for coronary blood flow?
Aortic pressure and wall pressure ## Footnote Wall pressure is particularly high during systole.
58
What happens if wall pressure is higher than aortic pressure?
Reverse coronary blood flow can occur.
59
What is the formula for calculating the area for coronary perfusion?
Area = delta P * time
60
What is the significance of diastolic time in coronary perfusion?
More diastolic time allows for better coronary perfusion.
61
True or False: An increase in heart rate generally allows more time for coronary perfusion.
False ## Footnote Increased heart rate typically reduces the time available for diastole and coronary perfusion.
62
What happens to coronary perfusion when heart rate increases in someone with coronary artery disease?
It becomes a significant problem.
63
What is the importance of the middle third of diastole?
It is crucial for coronary perfusion, especially in patients with coronary artery disease.
64
What occurs during aortic stenosis regarding left ventricular pressure?
Left ventricular pressure must exceed aortic pressure significantly.
65
How does aortic regurgitation affect diastolic blood pressure?
It likely lowers diastolic blood pressure.
66
Fill in the blank: Ventricular pressure must be ______ than aortic pressure for ejection to occur.
higher
67
What can happen when ventricular pressure is higher than aortic pressure during systole?
It can cause retrograde coronary perfusion.
68
What is the effect of mitral stenosis on atrial pressure?
Atrial pressures are likely elevated.
69
What compensatory mechanism occurs due to reduced cardiac output from mitral stenosis?
The kidney expands blood volume.
70
What happens to the atrial pressure during mitral regurgitation?
Atrial pressure builds up significantly.
71
Describe the impact of increased heart rate on diastolic filling in a healthy heart.
It removes part of the middle phase of diastole, which is not critical for filling.
72
What does the area under the curve in pressure-time graphs indicate?
It reflects the time and pressure available for coronary perfusion.
73
What is the effect of deep spinal anesthesia on heart activity?
It reduces the activity of the heart without creating a heart pumping problem. ## Footnote The sympathetic nervous system (SNS) stimulation of the heart is low, so removing it does not significantly affect heart output.
74
What is the relationship between filling pressure and cardiac output during deep spinal anesthesia?
Filling pressure is low, leading to low cardiac output, which is a circulatory problem rather than a heart pumping problem. ## Footnote Cardiac output is affected by circulation, not the heart itself.
75
What are the three important parts of the CVP waveform?
A wave, C wave, V wave. ## Footnote Each wave represents different phases of atrial and ventricular activities.
76
What does the A wave in the CVP waveform represent?
Atrial contraction. ## Footnote It causes a spike in the CVP waveform as blood is pushed forward.
77
What causes the C wave in the CVP waveform?
Backward bulging of AV valves during ventricular contraction. ## Footnote This occurs as the ventricle contracts rapidly.
78
What is the V wave in the CVP waveform associated with?
Atrial filling while the AV valves are closed. ## Footnote Blood returns to the atria but cannot enter the ventricle until the valves open.
79
What is the X descent in the CVP waveform?
It occurs after the C wave when the atria are empty. ## Footnote This results from the AV valves no longer bulging backwards.
80
What does the Y descent in the CVP waveform indicate?
It occurs after the V wave when the AV valves open, allowing rapid filling of the ventricle. ## Footnote This leads to a decrease in atrial pressure.
81
What is the approximate normal cardiac output?
5 liters per minute. ## Footnote This is a standard measurement in cardiovascular physiology.
82
What is the range of normal systemic vascular resistance (SVR)?
800 to 1600. ## Footnote This value is significantly higher than pulmonary vascular resistance.
83
What is the range of normal pulmonary vascular resistance (PVR)?
40 to 100. ## Footnote PVR is much lower than SVR due to lower resistance in the pulmonary circulation.
84
What formula is used to calculate systemic vascular resistance?
SVR = (Mean arterial pressure - CVP) / Cardiac output. ## Footnote This formula helps estimate vascular resistance in clinical settings.
85
What does the term 'CGS units' refer to?
Centimeters, grams, seconds. ## Footnote This is a shorthand for expressing certain physiological measurements.
86
What is the normal left atrial pressure in healthy individuals?
Approximately 8 mmHg. ## Footnote This is a common reference point for assessing left heart function.
87
What is the relationship between systemic vascular resistance and pulmonary vascular resistance?
SVR is several times higher than PVR. ## Footnote This difference is due to the distinct pressures in systemic and pulmonary circulations.
88
What is the definition of a Peripheral Resistance Unit (PRU)?
It is a measure of vascular resistance defined as delta P divided by flow. ## Footnote This unit simplifies the understanding of resistance in the peripheral circulation.
89
What is the normal peripheral vascular resistance for systemic circulation?
1 Peripheral Resistance Unit. ## Footnote This indicates a standard measure of resistance in healthy individuals.
90
How can you convert Peripheral Resistance Units to CGS units?
Multiply by 1333. ## Footnote This conversion aligns the units with the expected physiological ranges.
91
What is the normal vascular resistance for systemic circulation?
One unit ## Footnote Normal resistance for systemic circulation is typically considered to be one unit.
92
How do you convert systemic vascular resistance into CGS units?
Multiply by 1333 ## Footnote This conversion is necessary to express vascular resistance in CGS units.
93
What is the mean pulmonary arterial pressure in the context of pulmonary circulation?
16 mmHg ## Footnote This pressure is used to calculate pulmonary vascular resistance.
94
What is the left atrial pressure considered in the calculation of pulmonary vascular resistance?
2 mmHg ## Footnote This value is used to determine the difference in pressure affecting resistance.
95
What is the approximate pulmonary vascular resistance compared to systemic vascular resistance?
About 1/7 ## Footnote This indicates that pulmonary vascular resistance is significantly lower than systemic vascular resistance.
96
What general trend is observed regarding cardiac output during normal breathing cycles?
It can move left and right depending on pleural pressure ## Footnote This indicates the influence of thoracic pressure on venous return and cardiac output.
97
What happens to venous return to the heart when pleural pressure increases?
It becomes harder to get blood back to the heart ## Footnote Increased pleural pressure reduces venous return, affecting cardiac output.
98
During inspiration, what happens to central venous pressure (CVP)?
CVP drops dramatically ## Footnote This drop in CVP is significant for understanding venous return dynamics.
99
What effect does a negative thoracic pressure have on veins during inspiration?
It pulls on the walls of the veins, reducing their internal pressure ## Footnote This reduction facilitates venous return to the heart.
100
What is the initial effect of inspiration on cardiac output?
It may drop slightly ## Footnote The drop occurs due to reduced preload, affecting the heart's ability to pump effectively.
101
What happens to preload for the left side of the heart during early inspiration?
It drops significantly ## Footnote This drop is due to reduced venous return and pressure in the pulmonary circulation.
102
What is the relationship between thoracic pressure and pulmonary arterial pressure during inspiration?
Pulmonary arterial pressure drops ## Footnote This is due to the effects of negative thoracic pressure on the pulmonary circulation.
103
What happens to cardiac output from the left ventricle during early inspiration?
It is dramatically reduced ## Footnote This reduction is primarily due to decreased preload.
104
True or False: During early inspiration, afterload for the left heart changes significantly.
False ## Footnote Afterload remains relatively constant because the aorta has thick walls and is not affected by thoracic pressure.
105
What happens to the right heart's output during inspiration?
It does not reduce significantly ## Footnote The right heart is affected by both preload and afterload, but the changes are not as pronounced as for the left heart.
106
What is the expected trend for cardiac output from the right heart during early inspiration?
It may slightly increase ## Footnote This is due to reduced afterload despite a drop in preload.
107
Fill in the blank: During inspiration, the _______ for the right heart is reduced.
afterload ## Footnote A reduction in afterload can facilitate the right heart's ability to pump blood.
108
What is the overall effect on cardiac output during the respiratory cycle?
Initially drops, then increases ## Footnote The initial drop is due to reduced preload, but as the thorax fills, cardiac output increases.