Podcast
Questions and Answers
What is the term for the maximum volume of blood in the left ventricle at the end of diastole?
What is the term for the maximum volume of blood in the left ventricle at the end of diastole?
What occurs during the phase known as systole?
What occurs during the phase known as systole?
What is referred to as the minimum volume of blood in the left ventricle at the end of systole?
What is referred to as the minimum volume of blood in the left ventricle at the end of systole?
How can end diastolic volume and end systolic volume be utilized in cardiac physiology?
How can end diastolic volume and end systolic volume be utilized in cardiac physiology?
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What happens to the volume of blood in the left ventricle as it contracts during the cardiac cycle?
What happens to the volume of blood in the left ventricle as it contracts during the cardiac cycle?
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What term describes the total blood volume ejected by the left ventricle during one contraction?
What term describes the total blood volume ejected by the left ventricle during one contraction?
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During which phase does the left ventricle achieve its least volume?
During which phase does the left ventricle achieve its least volume?
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Which statement best describes the relationship between end diastolic volume and end systolic volume?
Which statement best describes the relationship between end diastolic volume and end systolic volume?
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What primarily determines the systolic blood pressure?
What primarily determines the systolic blood pressure?
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Which equation defines stroke volume?
Which equation defines stroke volume?
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How is mean arterial pressure calculated?
How is mean arterial pressure calculated?
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What does an increase in total peripheral resistance (TPR) typically cause?
What does an increase in total peripheral resistance (TPR) typically cause?
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What is the effect of vasodilation of arterioles on total peripheral resistance?
What is the effect of vasodilation of arterioles on total peripheral resistance?
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In a patient with heart failure, how does the stroke volume and pulse pressure typically present?
In a patient with heart failure, how does the stroke volume and pulse pressure typically present?
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Which of the following is true about end diastolic volume (EDV)?
Which of the following is true about end diastolic volume (EDV)?
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If the end diastolic volume is 150 mL and the end systolic volume is 75 mL, what is the left ventricular ejection fraction?
If the end diastolic volume is 150 mL and the end systolic volume is 75 mL, what is the left ventricular ejection fraction?
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Which term refers to the volume of blood returned to the heart during each cardiac cycle?
Which term refers to the volume of blood returned to the heart during each cardiac cycle?
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How is pulse pressure defined?
How is pulse pressure defined?
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What does a higher end systolic volume indicate?
What does a higher end systolic volume indicate?
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What does the body spend more time in during the cardiac cycle?
What does the body spend more time in during the cardiac cycle?
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If a patient exhibits high total peripheral resistance, what might be an expected effect on their blood pressure during diastole?
If a patient exhibits high total peripheral resistance, what might be an expected effect on their blood pressure during diastole?
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Which factor is primarily responsible for the increase in preload?
Which factor is primarily responsible for the increase in preload?
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What effect does raising heart rate have on preload?
What effect does raising heart rate have on preload?
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How does nitroglycerin reduce preload in patients with angina?
How does nitroglycerin reduce preload in patients with angina?
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What is the consequence of chronically high afterload on the left ventricle?
What is the consequence of chronically high afterload on the left ventricle?
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What happens to stroke volume when afterload increases?
What happens to stroke volume when afterload increases?
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What would lead to a decrease in LVEDV?
What would lead to a decrease in LVEDV?
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How does aortic stenosis affect afterload?
How does aortic stenosis affect afterload?
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Which condition would likely result in increased peripheral resistance and higher afterload?
Which condition would likely result in increased peripheral resistance and higher afterload?
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What effect does decreased blood pressure have on the afterload experienced by the heart?
What effect does decreased blood pressure have on the afterload experienced by the heart?
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What occurs to the left ventricle if there are heightened forces opposing outflow?
What occurs to the left ventricle if there are heightened forces opposing outflow?
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Which of the following describes a characteristic of LVEDP?
Which of the following describes a characteristic of LVEDP?
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Which statement best reflects the relationship between preload and afterload?
Which statement best reflects the relationship between preload and afterload?
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In a state of dehydration, what will happen to the cardiac output?
In a state of dehydration, what will happen to the cardiac output?
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What is the relationship between preload and cardiac output?
What is the relationship between preload and cardiac output?
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Which of the following factors is NOT a determinant of cardiac output?
Which of the following factors is NOT a determinant of cardiac output?
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How can one increase preload in a clinical setting?
How can one increase preload in a clinical setting?
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What is the primary effect of increasing preload on the heart's workload?
What is the primary effect of increasing preload on the heart's workload?
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Which of the following is a consequence of a decreased heart rate?
Which of the following is a consequence of a decreased heart rate?
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Which physiological mechanism primarily facilitates the increase of preload during blood loss?
Which physiological mechanism primarily facilitates the increase of preload during blood loss?
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What happens to stroke volume if preload decreases?
What happens to stroke volume if preload decreases?
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Which statement best describes preload?
Which statement best describes preload?
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How can stroke volume be calculated?
How can stroke volume be calculated?
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When the heart is at rest, what generally happens to cardiac output?
When the heart is at rest, what generally happens to cardiac output?
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What physiological parameter correlates with the volume of blood returning to the heart at the end of diastole?
What physiological parameter correlates with the volume of blood returning to the heart at the end of diastole?
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Which of these options can lead to a decrease in end diastolic volume?
Which of these options can lead to a decrease in end diastolic volume?
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Which factor is primarily affected when there is an increase in contractility?
Which factor is primarily affected when there is an increase in contractility?
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What physiological state is described by the heart needing to work harder due to more cardiac output?
What physiological state is described by the heart needing to work harder due to more cardiac output?
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What is the primary effect of the sympathetic nervous system on contractility?
What is the primary effect of the sympathetic nervous system on contractility?
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Which condition is characterized by poor contractility?
Which condition is characterized by poor contractility?
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What happens to the end diastolic volume (EDV) as heart rate increases?
What happens to the end diastolic volume (EDV) as heart rate increases?
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What is the role of calcium channel blockers on contractility?
What is the role of calcium channel blockers on contractility?
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How does increased contractility affect ejection fraction?
How does increased contractility affect ejection fraction?
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What is a common response of the body to physiologic stress in terms of cardiac function?
What is a common response of the body to physiologic stress in terms of cardiac function?
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What effect do sympathomimetic drugs have on the heart?
What effect do sympathomimetic drugs have on the heart?
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In heart failure, what happens to stroke volume?
In heart failure, what happens to stroke volume?
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What is a major consequence of increased contractility on oxygen demand?
What is a major consequence of increased contractility on oxygen demand?
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What mechanism is primarily responsible for reducing contractility during cardiac events?
What mechanism is primarily responsible for reducing contractility during cardiac events?
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What is affected by aortic valve replacement in stenotic valves?
What is affected by aortic valve replacement in stenotic valves?
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What is the relationship between stroke volume, end diastolic volume (EDV), and end systolic volume (ESV)?
What is the relationship between stroke volume, end diastolic volume (EDV), and end systolic volume (ESV)?
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What physiological factor affects contractility during high levels of carbon dioxide in the blood?
What physiological factor affects contractility during high levels of carbon dioxide in the blood?
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What is the outcome of increased heart rate with unchanged contractility, preload, and afterload?
What is the outcome of increased heart rate with unchanged contractility, preload, and afterload?
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What effect does an increase in heart rate have on stroke volume under physiological conditions?
What effect does an increase in heart rate have on stroke volume under physiological conditions?
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What primarily controls the relationship between heart rate and contractility?
What primarily controls the relationship between heart rate and contractility?
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Under what conditions does a higher heart rate lead to reduced cardiac output?
Under what conditions does a higher heart rate lead to reduced cardiac output?
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What happens to left ventricular filling time when the heart beats at pathological heart rates?
What happens to left ventricular filling time when the heart beats at pathological heart rates?
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Which of the following represents the effect of stroke work related to heart physiology?
Which of the following represents the effect of stroke work related to heart physiology?
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Why might a person experiencing ventricular tachycardia be at risk of losing consciousness?
Why might a person experiencing ventricular tachycardia be at risk of losing consciousness?
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In what scenario does the relationship between cardiac output and heart rate appear linear?
In what scenario does the relationship between cardiac output and heart rate appear linear?
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What physiological parameter reflects the demand placed upon the heart during increased activity?
What physiological parameter reflects the demand placed upon the heart during increased activity?
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Why does elevated heart activity during exercise not reach pathological frequency levels?
Why does elevated heart activity during exercise not reach pathological frequency levels?
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How does increased heart work relate to oxygen extraction in the blood?
How does increased heart work relate to oxygen extraction in the blood?
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Which of the following correctly describes a consequence of higher afterload?
Which of the following correctly describes a consequence of higher afterload?
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What situation exemplifies increased cardiac output at higher heart rates?
What situation exemplifies increased cardiac output at higher heart rates?
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Which of the following best describes the relationship between oxygen extraction and heart workload?
Which of the following best describes the relationship between oxygen extraction and heart workload?
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What is the primary reason cardiac output can decrease at high heart rates?
What is the primary reason cardiac output can decrease at high heart rates?
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The amount of blood in the left ventricle at the end of diastole is called the end ______ volume.
The amount of blood in the left ventricle at the end of diastole is called the end ______ volume.
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Systole is the phase when the left ventricle ______ and pushes blood out.
Systole is the phase when the left ventricle ______ and pushes blood out.
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The smallest volume of blood the left ventricle holds during the cardiac cycle is called the end ______ volume.
The smallest volume of blood the left ventricle holds during the cardiac cycle is called the end ______ volume.
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The left ventricle goes back and forth between the end diastolic volume and the end ______ volume.
The left ventricle goes back and forth between the end diastolic volume and the end ______ volume.
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The amount of blood that the left ventricle can eject with each contraction is defined by the left ventricular ______ fraction.
The amount of blood that the left ventricle can eject with each contraction is defined by the left ventricular ______ fraction.
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Diastole is the phase in which the left ventricle ______ with blood.
Diastole is the phase in which the left ventricle ______ with blood.
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The cardiac cycle consists of alternating phases known as ______ and diastole.
The cardiac cycle consists of alternating phases known as ______ and diastole.
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The maximum volume of blood in the left ventricle during the cardiac cycle is known as the end diastolic ______.
The maximum volume of blood in the left ventricle during the cardiac cycle is known as the end diastolic ______.
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The sympathetic nervous system is the major controller of heart rate and ______.
The sympathetic nervous system is the major controller of heart rate and ______.
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In real life, when heart rate increases, it is usually accompanied by an increase in ______.
In real life, when heart rate increases, it is usually accompanied by an increase in ______.
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At pathologic heart rates, there is very short ______, leading to decreased filling time.
At pathologic heart rates, there is very short ______, leading to decreased filling time.
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Ventricular tachycardia is an example of a condition where the heart rate can exceed ______ beats per minute.
Ventricular tachycardia is an example of a condition where the heart rate can exceed ______ beats per minute.
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The amount of work the heart has to do is controlled by preload, afterload, ______, and heart rate.
The amount of work the heart has to do is controlled by preload, afterload, ______, and heart rate.
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Stroke work is proportional to stroke volume times the mean ______.
Stroke work is proportional to stroke volume times the mean ______.
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If the heart generates more stroke volume, that means there is more ______ work.
If the heart generates more stroke volume, that means there is more ______ work.
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When the heart works harder, the blood that enters the coronary sinus has ______ oxygen.
When the heart works harder, the blood that enters the coronary sinus has ______ oxygen.
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A rise in cardiac output when heart rate increases is primarily due to changes in ______ and contractility.
A rise in cardiac output when heart rate increases is primarily due to changes in ______ and contractility.
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The only time a higher heart rate leads to a fall in cardiac output is at ______ heart rates.
The only time a higher heart rate leads to a fall in cardiac output is at ______ heart rates.
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The classic example of a situation where the heart doesn't fill properly due to rapid beating is ______ tachycardia.
The classic example of a situation where the heart doesn't fill properly due to rapid beating is ______ tachycardia.
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The relationship between cardiac output and heart rate has a linear increasing ______.
The relationship between cardiac output and heart rate has a linear increasing ______.
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More oxygen is used when the work of the heart ______.
More oxygen is used when the work of the heart ______.
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A higher heart rate leads to more cardiac output, which is essential during ______.
A higher heart rate leads to more cardiac output, which is essential during ______.
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The heart's contractility can be represented by the ______ fraction.
The heart's contractility can be represented by the ______ fraction.
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The main way to increase contractility in the human body is through the ______ nervous system.
The main way to increase contractility in the human body is through the ______ nervous system.
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Patients with heart failure typically exhibit ______ contractility.
Patients with heart failure typically exhibit ______ contractility.
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Ejection fraction is an index of ______.
Ejection fraction is an index of ______.
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Drugs like dopamine and epinephrine are classified as ______ drugs.
Drugs like dopamine and epinephrine are classified as ______ drugs.
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When contractility rises, there is a lower end systolic ______.
When contractility rises, there is a lower end systolic ______.
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Increased heart rate can lead to a decrease in end diastolic ______.
Increased heart rate can lead to a decrease in end diastolic ______.
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Calcium channel blockers, such as verapamil, are used to ______ contractility.
Calcium channel blockers, such as verapamil, are used to ______ contractility.
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The heart's workload increases with higher heart ______.
The heart's workload increases with higher heart ______.
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Conditions such as hypoxia and hypercapnia can ______ contractility.
Conditions such as hypoxia and hypercapnia can ______ contractility.
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The sympathetic nervous system activates ______ receptors on heart muscle cells to increase contractility.
The sympathetic nervous system activates ______ receptors on heart muscle cells to increase contractility.
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In patients exercising, high contractility results in a very high ______ fraction.
In patients exercising, high contractility results in a very high ______ fraction.
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Myocytes release more calcium from the ______ reticulum to increase contractility.
Myocytes release more calcium from the ______ reticulum to increase contractility.
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Drugs that block the sympathetic nervous system, like ______ blockers, lower contractility.
Drugs that block the sympathetic nervous system, like ______ blockers, lower contractility.
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Physiological stress activates the sympathetic nervous system, leading to increased ______.
Physiological stress activates the sympathetic nervous system, leading to increased ______.
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The left ventricular ______ fraction is the percentage of blood ejected with each squeeze of the chamber.
The left ventricular ______ fraction is the percentage of blood ejected with each squeeze of the chamber.
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Stroke volume is calculated by subtracting the end systolic volume from the end ______ volume.
Stroke volume is calculated by subtracting the end systolic volume from the end ______ volume.
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The volume of blood pushed out of the left ventricle during each cardiac cycle is called ______ output.
The volume of blood pushed out of the left ventricle during each cardiac cycle is called ______ output.
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Total peripheral resistance (TPR) is the resistance to blood flow from ______ structures.
Total peripheral resistance (TPR) is the resistance to blood flow from ______ structures.
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The difference between systolic and diastolic blood pressure is called ______ pressure.
The difference between systolic and diastolic blood pressure is called ______ pressure.
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The lowest blood pressure in the central aorta is referred to as the ______ blood pressure.
The lowest blood pressure in the central aorta is referred to as the ______ blood pressure.
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Vasoconstriction of arterioles tends to raise the total peripheral ______.
Vasoconstriction of arterioles tends to raise the total peripheral ______.
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A normal left ventricular ejection fraction for a healthy heart is about ______% or 60%.
A normal left ventricular ejection fraction for a healthy heart is about ______% or 60%.
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The major vessels that determine the total peripheral resistance are the ______.
The major vessels that determine the total peripheral resistance are the ______.
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Mean arterial pressure (MAP) can be calculated using diastolic blood pressure plus one third of the ______ pressure.
Mean arterial pressure (MAP) can be calculated using diastolic blood pressure plus one third of the ______ pressure.
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An important mechanism affecting diastolic pressure is the total ______ resistance.
An important mechanism affecting diastolic pressure is the total ______ resistance.
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With each cardiac cycle, the amount of ______ returned to the left ventricle should equal the cardiac output.
With each cardiac cycle, the amount of ______ returned to the left ventricle should equal the cardiac output.
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Patients with heart failure tend to have a very low stroke volume and a very low ______ pressure.
Patients with heart failure tend to have a very low stroke volume and a very low ______ pressure.
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As blood leaves the left ventricle, it drives up the blood pressure in the central ______.
As blood leaves the left ventricle, it drives up the blood pressure in the central ______.
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The formula for determining the mean arterial pressure involves adding 80 plus one third of the difference of ______.
The formula for determining the mean arterial pressure involves adding 80 plus one third of the difference of ______.
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Cardiac output is equal to the heart rate times the ______.
Cardiac output is equal to the heart rate times the ______.
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An increase in heart rate means more ______ for the heart.
An increase in heart rate means more ______ for the heart.
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The four determinants of cardiac output are preload, afterload, ______, and heart rate.
The four determinants of cardiac output are preload, afterload, ______, and heart rate.
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Preload refers to the volume of blood that fills the left ventricle during ______.
Preload refers to the volume of blood that fills the left ventricle during ______.
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An increase in preload leads to an increase in ______, and subsequently, cardiac output.
An increase in preload leads to an increase in ______, and subsequently, cardiac output.
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One way to increase preload is to infuse a unit of ______ into a patient.
One way to increase preload is to infuse a unit of ______ into a patient.
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Constricting veins can push more blood back into the heart and increase ______.
Constricting veins can push more blood back into the heart and increase ______.
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When the heart rate slows, it allows for more filling of the left ventricle, which results in increased ______.
When the heart rate slows, it allows for more filling of the left ventricle, which results in increased ______.
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The degree of stretch on the myocardial fibers before contraction is referred to as ______.
The degree of stretch on the myocardial fibers before contraction is referred to as ______.
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Increased preload raises the end diastolic ______ returning to the left ventricle.
Increased preload raises the end diastolic ______ returning to the left ventricle.
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During exercise, the body naturally responds by increasing cardiac ______.
During exercise, the body naturally responds by increasing cardiac ______.
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Any time there's more preload in the left ventricle, it generates more cardiac ______.
Any time there's more preload in the left ventricle, it generates more cardiac ______.
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The sympathetic nervous system causes vein ______ as a response to blood loss.
The sympathetic nervous system causes vein ______ as a response to blood loss.
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Venous tone determines how much ______ will be pushed out of the venous system and into the heart.
Venous tone determines how much ______ will be pushed out of the venous system and into the heart.
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Pooling blood in the veins is the mechanism of action of ______ drugs like nitroglycerin.
Pooling blood in the veins is the mechanism of action of ______ drugs like nitroglycerin.
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When preload decreases, there is less work for the ______.
When preload decreases, there is less work for the ______.
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The LVEDV is the volume of blood in the left ventricle when it has completed filling at the end of ______.
The LVEDV is the volume of blood in the left ventricle when it has completed filling at the end of ______.
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Afterload refers to forces that resist the flow of blood out of the left ______.
Afterload refers to forces that resist the flow of blood out of the left ______.
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If the aortic valve is ______, it can generate high afterload making it hard for blood to exit the left ventricle.
If the aortic valve is ______, it can generate high afterload making it hard for blood to exit the left ventricle.
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Chronically high afterload can lead to hypertrophy of the left ______.
Chronically high afterload can lead to hypertrophy of the left ______.
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When afterload increases, stroke ______ tends to decrease.
When afterload increases, stroke ______ tends to decrease.
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One way to increase afterload is if the mean blood ______ goes up.
One way to increase afterload is if the mean blood ______ goes up.
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Obstruction to outflow from the left ventricle can also significantly increase ______.
Obstruction to outflow from the left ventricle can also significantly increase ______.
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In cases of dehydration, patients will experience low LVEDV and low ______.
In cases of dehydration, patients will experience low LVEDV and low ______.
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More afterload results in the heart requiring more ______ to push blood out to the body.
More afterload results in the heart requiring more ______ to push blood out to the body.
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Drugs that lower blood pressure help to ______ afterload.
Drugs that lower blood pressure help to ______ afterload.
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The terms LVEDV and LVEDP are critical markers of ______.
The terms LVEDV and LVEDP are critical markers of ______.
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Flashcards
End Diastolic Volume
End Diastolic Volume
Maximum volume of blood in the left ventricle during the cardiac cycle's filling phase (diastole).
End Systolic Volume
End Systolic Volume
Minimum volume of blood in the left ventricle at the end of contraction (systole).
Cardiac Cycle
Cardiac Cycle
The sequence of events in the heart from one heartbeat to the next, involving filling, contraction, and emptying.
Diastole
Diastole
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Systole
Systole
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Left Ventricle
Left Ventricle
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Ejection Fraction
Ejection Fraction
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Echocardiogram
Echocardiogram
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MAP
MAP
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Cardiac Output
Cardiac Output
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What is the formula for cardiac output?
What is the formula for cardiac output?
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Preload
Preload
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What is the effect of increasing preload?
What is the effect of increasing preload?
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LVEDV
LVEDV
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How does adding volume affect preload?
How does adding volume affect preload?
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How does venous constriction affect preload?
How does venous constriction affect preload?
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How does slowing heart rate affect preload?
How does slowing heart rate affect preload?
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Afterload
Afterload
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Contractility
Contractility
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What are the 4 determinants of cardiac output?
What are the 4 determinants of cardiac output?
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What is the role of the sympathetic nervous system in preload?
What is the role of the sympathetic nervous system in preload?
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Why is preload important clinically?
Why is preload important clinically?
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Venous Tone
Venous Tone
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What decreases Preload?
What decreases Preload?
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What is Nitroglycerin?
What is Nitroglycerin?
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What causes Decreased Preload?
What causes Decreased Preload?
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What happens when Afterload Increases?
What happens when Afterload Increases?
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What causes Increased Afterload?
What causes Increased Afterload?
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Chronic High Afterload
Chronic High Afterload
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How to Decrease Afterload?
How to Decrease Afterload?
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Increased Afterload and ESV
Increased Afterload and ESV
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What is contractility?
What is contractility?
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How does contractility affect stroke volume?
How does contractility affect stroke volume?
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What is ejection fraction?
What is ejection fraction?
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How does the sympathetic nervous system affect contractility?
How does the sympathetic nervous system affect contractility?
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What are some drugs that increase contractility?
What are some drugs that increase contractility?
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How do beta blockers affect contractility?
How do beta blockers affect contractility?
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What is the role of calcium in contractility?
What is the role of calcium in contractility?
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How does digoxin affect contractility?
How does digoxin affect contractility?
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How do calcium channel blockers affect contractility?
How do calcium channel blockers affect contractility?
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What is the main way to increase heart rate?
What is the main way to increase heart rate?
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How do heart rate and contractility relate?
How do heart rate and contractility relate?
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How does heart rate affect end-diastolic volume?
How does heart rate affect end-diastolic volume?
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How does heart rate affect stroke volume?
How does heart rate affect stroke volume?
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What are the four main determinants of cardiac output?
What are the four main determinants of cardiac output?
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Heart Rate and Contractility Relationship
Heart Rate and Contractility Relationship
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Stroke Volume and Heart Rate in Real Life
Stroke Volume and Heart Rate in Real Life
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Cardiac Output and Heart Rate Relationship
Cardiac Output and Heart Rate Relationship
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Pathologic Heart Rate Effect
Pathologic Heart Rate Effect
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Ventricular Tachycardia and Cardiac Output
Ventricular Tachycardia and Cardiac Output
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Stroke Work
Stroke Work
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Factors Affecting Cardiac Work
Factors Affecting Cardiac Work
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Cardiac Work and Oxygen Demand
Cardiac Work and Oxygen Demand
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Oxygen Extraction and Cardiac Work
Oxygen Extraction and Cardiac Work
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Preload and Cardiac Work
Preload and Cardiac Work
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Afterload and Cardiac Work
Afterload and Cardiac Work
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Contractility and Cardiac Work
Contractility and Cardiac Work
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Heart Rate and Cardiac Work
Heart Rate and Cardiac Work
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Coronary Sinus Oxygen Content
Coronary Sinus Oxygen Content
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Left Ventricular Ejection Fraction
Left Ventricular Ejection Fraction
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Stroke Volume
Stroke Volume
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Venous Return
Venous Return
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Total Peripheral Resistance (TPR)
Total Peripheral Resistance (TPR)
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What are the major vessels influencing TPR?
What are the major vessels influencing TPR?
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What is the relationship between arteriole constriction and TPR?
What is the relationship between arteriole constriction and TPR?
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What is the relationship between arteriole dilation and TPR?
What is the relationship between arteriole dilation and TPR?
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Systolic Blood Pressure
Systolic Blood Pressure
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Diastolic Blood Pressure
Diastolic Blood Pressure
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End Diastolic Volume (EDV)
End Diastolic Volume (EDV)
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End Systolic Volume (ESV)
End Systolic Volume (ESV)
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Ejection Fraction (EF)
Ejection Fraction (EF)
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What are the two main phases of the cardiac cycle?
What are the two main phases of the cardiac cycle?
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What is the relationship between EDV, ESV, and EF?
What is the relationship between EDV, ESV, and EF?
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What is preload?
What is preload?
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What is afterload?
What is afterload?
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Arterioles
Arterioles
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Vasoconstriction
Vasoconstriction
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Vasodilation
Vasodilation
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Pulse Pressure
Pulse Pressure
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Mean Arterial Pressure (MAP)
Mean Arterial Pressure (MAP)
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How is MAP calculated?
How is MAP calculated?
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What increases contractility?
What increases contractility?
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What decreases contractility?
What decreases contractility?
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What is the main regulator of heart rate?
What is the main regulator of heart rate?
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How does heart rate affect cardiac output?
How does heart rate affect cardiac output?
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What happens to end-diastolic volume (EDV) with a higher heart rate?
What happens to end-diastolic volume (EDV) with a higher heart rate?
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How does contractility relate to heart rate?
How does contractility relate to heart rate?
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How is cardiac output clinically measured?
How is cardiac output clinically measured?
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Why is understanding cardiac output important clinically?
Why is understanding cardiac output important clinically?
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What is the relationship between stroke volume and heart rate in real life?
What is the relationship between stroke volume and heart rate in real life?
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What is the effect of increasing heart rate beyond the normal range?
What is the effect of increasing heart rate beyond the normal range?
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What is Mean Arterial Pressure (MAP)?
What is Mean Arterial Pressure (MAP)?
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What is Cardiac Output?
What is Cardiac Output?
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How does increasing Afterload affect the heart?
How does increasing Afterload affect the heart?
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What is the role of the sympathetic nervous system in heart function?
What is the role of the sympathetic nervous system in heart function?
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What is the relationship between cardiac output, preload, afterload, contractility, and heart rate?
What is the relationship between cardiac output, preload, afterload, contractility, and heart rate?
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How do increased heart rate and contractility affect cardiac output?
How do increased heart rate and contractility affect cardiac output?
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What is stroke work?
What is stroke work?
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How does increased cardiac work affect oxygen demand?
How does increased cardiac work affect oxygen demand?
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Nitroglycerin
Nitroglycerin
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How do LVEDV and LVEDP relate to preload?
How do LVEDV and LVEDP relate to preload?
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Stroke volume and Heart Rate
Stroke volume and Heart Rate
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Why Does This Happen?
Why Does This Happen?
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Cardiac Output and Heart Rate
Cardiac Output and Heart Rate
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What About Pathologic Heart Rates?
What About Pathologic Heart Rates?
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Ventricular Tachycardia
Ventricular Tachycardia
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Heart's Oxygen Extraction
Heart's Oxygen Extraction
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Coronary Sinus Oxygen
Coronary Sinus Oxygen
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Preload's Effect on Cardiac Work
Preload's Effect on Cardiac Work
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Afterload's Effect on Cardiac Work
Afterload's Effect on Cardiac Work
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Contractility's Effect on Cardiac Work
Contractility's Effect on Cardiac Work
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Heart Rate's Effect on Cardiac Work
Heart Rate's Effect on Cardiac Work
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Determinants of Cardiac Output
Determinants of Cardiac Output
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Study Notes
Cardiac Cycle Volumes and Ejection Fraction
- End Diastolic Volume (EDV): Maximum volume of blood in the left ventricle during filling (diastole).
- End Systolic Volume (ESV): Minimum volume of blood in the left ventricle after contraction (systole).
- Left Ventricular Ejection Fraction (LVEF): Percentage of blood ejected from the left ventricle with each contraction. Calculated as [(EDV - ESV) / EDV] * 100. Normal range is approximately 55-60%.
Stroke Volume and Cardiac Output
- Stroke Volume (SV): Volume of blood ejected from the left ventricle per heartbeat. Calculated as EDV - ESV.
- Cardiac Output (CO): Volume of blood pumped by the heart per minute. Calculated as SV x Heart Rate.
- Venous Return: Blood returning to the heart; should equal cardiac output.
- Total Peripheral Resistance (TPR) / Systemic Vascular Resistance (SVR): Resistance to blood flow in the peripheral vessels, mainly determined by arteriolar constriction/dilation.
Blood Pressure
- Systolic Blood Pressure: Highest pressure in the central aorta during ventricular contraction. Largely determined by stroke volume.
- Diastolic Blood Pressure: Lowest pressure in the central aorta during ventricular relaxation. Largely determined by total peripheral resistance.
- Pulse Pressure: Difference between systolic and diastolic pressure (systolic - diastolic). Proportional to stroke volume.
- Mean Arterial Pressure (MAP): Average pressure in the arterial system over a cardiac cycle. Calculated as diastolic pressure + [1/3 * (systolic – diastolic)].
Determinants of Cardiac Output
- Preload: Volume of blood in the left ventricle at the end of diastole, stretching the myocardial fibers. Increased preload = increased EDV = increased SV = increased CO. Increased preload requires more heart work and oxygen.
- Increased preload causes: Increased intravascular volume, venous constriction, slower heart rate.
- Decreased preload causes: Blood loss, dehydration, nitrate drugs (dilate veins).
- Afterload: Forces opposing blood ejection out of the left ventricle. Increased afterload = increased ESV = decreased SV = decreased CO. Increased afterload requires more work and oxygen use.
- Increased afterload causes: High blood pressure, aortic stenosis, hypertrophic cardiomyopathy.
- Decreased afterload causes: Lowering blood pressure, treating aortic stenosis or hypertrophic cardiomyopathy
- Contractility: Strength of ventricular contraction. Increased contractility = decreased ESV = increased SV = increased CO. Increased contractility requires more work and oxygen.
- Increased contractility caused by: Sympathetic nervous system (beta 1 receptors), sympathomimetic drugs like dobutamine, epinephrine, digoxin.
- Decreased contractility caused by: Beta blockers, calcium channel blockers, hypoxia, acidosis.
- Heart Rate: Number of heartbeats per minute. Increased heart rate = potentially increased CO, especially in the physiological range. Increased heart rate in isolation, without change in other parameters, decreases EDV and thereby SV at very high rates, leading to decreased CO.
Heart Rate and Cardiac Output Relationship
- Physiological heart rates increase cardiac output by increasing both heart rate and contractility.
- Pathological heart rates (e.g., >250 bpm) decrease cardiac output due to insufficient filling time in diastole.
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Description
Test your knowledge on the cardiac cycle, including important concepts such as End Diastolic Volume, End Systolic Volume, and Left Ventricular Ejection Fraction. Understand stroke volume and cardiac output, as well as the factors that affect venous return and vascular resistance. This quiz will help reinforce your understanding of cardiovascular physiology.
