[Exam 1] Lecture 5: More Heart Valves, Cardiac Anatomy, CVP waveforms, Flashcards
1
Q
What is the role of the right vagus nerve in heart innervation?
A
Handles the SA node
The SA node is responsible for initiating the heartbeat.
2
Q
What does the left vagus nerve primarily innervate?
A
Handles the AV node
The AV node coordinates the electrical signals between the atria and ventricles.
3
Q
True or False: Sympathetic innervation covers less of the heart muscle than the vagus nerve.
A
False
Sympathetic innervation is widespread and covers more of the ventricular muscle.
4
Q
What happens to heart rate if vagus nerve input is removed?
A
Heart rate goes up significantly
5
Q
What is the typical activity level of the vagus nerves in a healthy resting heart compared to sympathetic nerves?
A
Vagus nerves are more active than sympathetic nerves
6
Q
What is the innermost layer surrounding the heart called?
A
Serous pericardium
7
Q
What is the function of the visceral layer of the serous pericardium?
A
Covers the outside of the heart and reduces friction
8
Q
What is the fibrous pericardium?
A
The outer, tougher layer of the pericardium
9
Q
What connects the cusps of the AV valves to the ventricular muscle?
A
Chordae tendinae
10
Q
What are papillary muscles?
A
Muscles that help reinforce AV valves during ventricular contraction
11
Q
Fill in the blank: The normal ejection fraction is approximately _______.
A
58%
12
Q
What are the two types of AV valves in the heart?
A
- Bicuspid valve (mitral valve)
- Tricuspid valve
13
Q
What happens to the heart valves if papillary muscles are damaged?
A
Can lead to valve problems
14
Q
What is the typical structure of the pulmonary and aortic valves?
A
Each has three cusps
15
Q
What occurs when heart valves do not fit together properly?
A
Can lead to backflow and heart stretching
16
Q
How do healthy heart valves appear when closed?
A
They fit together tightly without allowing leakage
17
Q
What can cause heart valves to become calcified?
A
Cholesterol buildup or infections
18
Q
What is the primary ion for conducting action potentials in the heart?
A
Sodium
19
Q
What is the function of gap junctions in cardiac muscle?
A
Allow electrical signals to flow between cells
20
Q
What is the criss-crossing pattern of muscle fibers in the ventricles compared to?
A
Ringing out a wet towel
21
Q
What is the ejection fraction formula based on a starting volume of 120 CCs and an ejection of 70 mLs?
A
70/120 = 58%
22
Q
What are the two cusps of the bicuspid valve called?
A
- Anterior cusp
- Posterior cusp
23
Q
What is the role of the septal cusp in the tricuspid valve?
A
Fastened into the wall of the interventricular septum
24
Q
True or False: The aortic valve has two cusps.
A
False
The aortic valve has three cusps.
25
What are the three cusps of the aortic valve named?
* Left cusp
* Right cusp
* Posterior cusp
26
What is stenosis in relation to heart valves?
Narrowing that prevents full opening of the valves
27
What are the locations where the coronary arteries attach to the aorta?
The openings for the left and right coronary arteries are located at the left and right cusps of the aortic valve respectively.
28
What happens to the aortic valve after blood ejection?
The aortic valve closes, and the pressure in the aorta is high.
29
During which phase does blood flow retrograde towards the coronary arteries?
During diastole, when the heart is filling.
30
True or False: The shape of the aortic valve cusps can affect coronary perfusion.
True.
31
What condition can lead to difficulties in coronary perfusion due to high resistance?
Aortic stenosis.
32
What are the three cusps of the pulmonary artery?
* Left cusp * Right cusp * Anterior cusp
33
What anatomical feature separates the electrical activity of the atria from the ventricles?
A layer of insulation made of cartilage.
34
What is the function of the cartilaginous ring in the heart?
It acts as an insulator to keep electrical activity in the atria separate from that in the ventricles.
35
How does the heart maintain communication between the atria and the ventricles?
Through a small opening in the cartilaginous ring that allows the AV node to send action potentials.
36
What are the cusps of the left AV valve?
* Anterior cusp * Posterior cusp * Commissural cusp
37
What are the two main branches of the left coronary artery?
* Left anterior descending artery (LAD) * Circumflex artery
38
What is the PDA and how is it typically formed?
The Posterior Descending Artery (PDA) is commonly a branch of the right coronary artery.
39
What is the name of the large vein situated on the posterior inferior part of the heart?
Great cardiac vein.
40
What is the coronary sinus and where does it lead?
The coronary sinus is continuous with the right atrium and collects deoxygenated blood from the coronary veins.
41
How much coronary blood flow is typically needed per minute for heart muscle?
70 mL of coronary blood flow per 100g of heart muscle.
42
Fill in the blank: The anterior cusp of the pulmonary artery is located on the _______ side of the heart.
anterior
43
What happens to coronary perfusion when the aortic valve is dysfunctional?
Blood may not be directed into the coronary arteries effectively.
44
What can happen if there's a continuous pathway between the atria and ventricles?
It may lead to potential electrical problems that could require ablation.
45
What is the typical coronary blood flow per 100 grams of heart muscle?
70 mL
## Footnote
This amount is necessary to meet the metabolic requirements of heart tissue.
46
What is the average coronary blood flow needed per minute for the heart?
225 mL
## Footnote
This is the amount required to satisfy the heart's metabolic needs.
47
Coronary blood flow is dependent on what factor?
Metabolic demand
## Footnote
Increased heart rate or stronger contractions require more blood flow.
48
When does the majority of coronary blood flow occur?
When pressures in the wall of the heart are low.
49
What happens to coronary blood flow during systole?
It decreases due to high resistance.
50
During which phase is coronary blood flow typically higher: systole or diastole?
Diastole
## Footnote
Both sides of the heart have more blood flow during diastole than systole.
51
What is the relationship between ventricular filling and coronary blood flow?
Coronary blood flow increases when ventricles are filling.
52
What type of blood vessels are embedded in the walls of the heart?
Endocardial and sub-endocardial blood vessels.
53
What does a drop in coronary perfusion during systole indicate?
High pressure in heart walls.
54
Which coronary artery typically supplies blood to high-pressure areas of the heart?
Left coronary artery.
55
Which coronary artery provides blood flow to lower pressure areas of the heart?
Right coronary artery.
56
How does coronary blood flow behave in a healthy patient during the cardiac cycle?
Right coronary artery perfusion is continuous throughout the cardiac cycle.
57
What unusual phenomenon can occur with left coronary blood flow during systole?
Negative coronary blood flow
## Footnote
Occurs when blood is pushed backward due to high ventricular pressure.
58
What drives coronary blood flow?
Delta P (pressure gradient).
59
What is the first pressure considered when calculating delta P for coronary blood flow?
Aortic pressure.
60
What happens when wall pressure exceeds aortic pressure?
Reverse coronary blood flow can occur.
61
Why is time an important factor in coronary perfusion?
It determines how long perfusion can occur, especially during diastole.
62
What happens to coronary perfusion when heart rate increases?
Available time for coronary perfusion decreases.
63
What is the significance of the area under the curve in relation to coronary perfusion?
It represents the relationship between pressure and time available for perfusion.
64
During diastole, when does the majority of ventricular filling occur?
At the very beginning of diastole.
65
What occurs in the middle of diastole regarding ventricular filling?
There is not much filling; most occurs early and late in diastole.
66
What happens during the middle third of diastole in a healthy heart?
Not much filling occurs during the middle third of diastole
## Footnote
Most ventricular filling happens at the beginning and end of diastole.
67
What is the effect of increasing heart rate on coronary perfusion?
Increases heart rate reduces time for coronary perfusion, which is problematic in patients with coronary artery disease
## Footnote
Healthy hearts can tolerate reduced filling time, but diseased hearts cannot.
68
What is the primary issue with aortic stenosis?
Obstruction of blood flow from the left ventricle requires higher interventricular pressures to eject blood
## Footnote
This increases the workload on the heart and can complicate coronary perfusion.
69
What happens to left ventricular pressure during aortic stenosis?
Left ventricular pressure must exceed aortic pressure significantly to eject blood
## Footnote
This pressure increase complicates perfusion of the left ventricle.
70
How does mitral stenosis affect atrial pressure?
Atrial pressures are elevated due to difficulties in filling the ventricle
## Footnote
This can lead to reduced cardiac output and compensatory mechanisms by the kidneys.
71
What occurs during aortic regurgitation?
Blood leaks back into the ventricle after being pumped into the aorta
## Footnote
This results in low diastolic blood pressure and widened pulse pressure.
72
What is the consequence of mitral insufficiency?
Blood is ejected into both the aorta and the atria, leading to high atrial pressure
## Footnote
Atria fill from both pulmonary veins and the ventricle.
73
What does the A wave in the CVP waveform represent?
A small increase in atrial and CVP pressures due to atrial contraction
## Footnote
This occurs because blood is pushed forward and backward during atrial contraction.
74
What causes the C wave in the CVP waveform?
Backwards bulging of the AV valves at the beginning of systole
## Footnote
This occurs as the ventricles contract rapidly.
75
What is the V wave in the CVP waveform indicative of?
Atrial filling while the AV valves are closed
## Footnote
This happens as blood returns from circulation during systole.
76
What does the X descent in the CVP waveform signify?
A reduction in atrial pressure after the C wave
## Footnote
This occurs when the atria are empty and the AV valves are no longer bulging backwards.
77
What is the Y descent in the CVP waveform?
A decrease in atrial pressure following the V wave
## Footnote
This occurs after the AV valves open and blood rapidly fills the ventricle.
78
What is the effect of deep spinal anesthesia on cardiac output?
Reduces filling pressure, leading to low cardiac output
## Footnote
This is primarily a circulatory problem, not a heart pumping problem.
79
What is diastole?
The phase of the cardiac cycle when the heart relaxes and fills with blood
## Footnote
Diastole is essential for understanding cardiac function and pressure dynamics.
80
What does the Y descent represent in the CVP waveform?
The lower pressure in the atria after the V wave when the valves open
## Footnote
It is an important feature in understanding venous pressure dynamics.
81
What occurs during the X descent in the CVP waveform?
It occurs after the C wave due to the valves no longer being pushed backwards
## Footnote
This reflects changes in atrial pressure during the cardiac cycle.
82
What is the average cardiac output as per Miller and Guyton?
Approximately five liters per minute
## Footnote
This is a key value in cardiovascular physiology.
83
How does systemic vascular resistance (SVR) compare to pulmonary vascular resistance (PVR)?
SVR is several times higher than PVR
## Footnote
This difference is crucial for understanding the pressure dynamics in systemic vs pulmonary circulation.
84
What is the normal clinical range for systemic vascular resistance (SVR)?
800 to 1600
## Footnote
These values are important for assessing cardiovascular health.
85
What is the formula for calculating systemic vascular resistance (SVR)?
MAP - CVP divided by cardiac output
## Footnote
MAP stands for mean arterial pressure, and CVP stands for central venous pressure.
86
What are the units for systemic vascular resistance (SVR)?
Millimeters of mercury divided by liters per minute
## Footnote
Alternatively referred to as CGS units.
87
What is the typical mean pulmonary arterial pressure in a healthy individual?
16
## Footnote
This value is used in calculations for pulmonary vascular resistance.
88
What is the purpose of using pulmonary arterial wedge pressure?
To estimate the pressure in the left atrium
## Footnote
This measurement is often used in critical care settings.
89
What is the normal left atrial pressure approximation?
8
## Footnote
This value is used in calculating pulmonary vascular resistance.
90
What is a Peripheral Resistance Unit (PRU)?
It is defined as delta P divided by flow
## Footnote
This unit simplifies the concept of vascular resistance.
91
What does a normal peripheral vascular resistance (SVR) equal in PRU?
1 peripheral resistance unit
## Footnote
This is an easier way to express vascular resistance.
92
What happens to cardiac output during a normal breathing cycle?
It can move left or right depending on pleural pressure
## Footnote
Changes in thoracic pressure influence venous return and cardiac output.
93
What effect does inspiration have on central venous pressure (CVP)?
CVP drops significantly
## Footnote
This drop in CVP aids in drawing blood into the thorax.
94
How does increased pleural pressure affect blood return to the heart?
It makes it harder to return blood
## Footnote
Increased chest pressure can reduce venous return.
95
What is the consequence of a negative pressure in the thorax during inspiration?
It pulls blood into the thorax, reducing preload initially
## Footnote
This can lead to a temporary decrease in cardiac output.
96
What happens to venous pressure during deep inspiration?
Venous pressure decreases, pulling blood into the chest
## Footnote
This effect is due to the compliance of the veins.
97
What is the relationship between right atrial pressure and venous pressure during inspiration?
Right atrial pressure may decrease as venous pressure drops
## Footnote
This can lead to a brief drop in cardiac output.
98
What happens to pressure in the chest during inspiration?
It drops pressure in the veins
## Footnote
This drop in pressure affects the thin-walled veins, making them more susceptible to being pulled apart.
99
How does the pressure drop in the chest affect the right atrium?
The right atrium may experience a slight pull of blood into the large veins in the chest due to the pressure drop.
100
What happens to cardiac output initially during inspiration?
Cardiac output may briefly drop for both the right and left heart.
101
How does the pulmonary circulation respond to a drop in chest pressure?
The pressures inside the pulmonary arteries and veins are reduced, decreasing preload for the left side of the heart.
102
What is the effect of inspiration on the preload of the left side of the heart?
Preload for the left side of the heart drops significantly during early inspiration.
103
True or False: The left heart experiences a reduction in afterload during inspiration.
False
## Footnote
The left heart does not experience a reduction in afterload due to its thick-walled aorta.
104
What happens to cardiac output from the left ventricle during inspiration?
It is likely reduced due to decreased preload and normal afterload.
105
What changes occur in pulmonary arterial pressures during inspiration?
Pulmonary arterial pressures drop as a result of the negative thoracic pressure.
106
Fill in the blank: The _______ pressure is affected by the drop in thoracic pressure during inspiration.
pulmonary venous
107
What is the general overview of cardiac output changes during the respiratory cycle?
Cardiac output may initially drop during inspiration, but eventually increases as the chest fills with blood.
108
How does the right heart's afterload change during inspiration?
Afterload for the right heart is probably reduced.
109
What happens to the right heart's cardiac output during inspiration?
It probably drops a little, but there is debate about whether it might slightly increase.
110
How does the left side of the heart respond to changes in preload and afterload during inspiration?
The left side experiences a drop in preload but normal afterload, leading to reduced cardiac output.
111
What is noted about the relationship between pulmonary arterial and venous pressures during inspiration?
If pulmonary arterial pressure drops, pulmonary venous pressure is also likely to drop.
112
What occurs within the first heartbeat or two of inspiration?
Transient changes in cardiac output and preload are noted.
113
What is the conclusion regarding cardiac output changes during early inspiration?
Cardiac output is likely reduced initially but may increase later as blood fills the chest.
