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Questions and Answers
What primary neurotransmitter is released by the sympathetic nervous system to increase heart rate?
What primary neurotransmitter is released by the sympathetic nervous system to increase heart rate?
Which statement accurately describes diastole?
Which statement accurately describes diastole?
Which factor is NOT known to increase heart rate?
Which factor is NOT known to increase heart rate?
What is the normal range for ejection fraction considered healthy?
What is the normal range for ejection fraction considered healthy?
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What is meant by preload in cardiac physiology?
What is meant by preload in cardiac physiology?
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Which measurement refers to the difference between systolic and diastolic blood pressure?
Which measurement refers to the difference between systolic and diastolic blood pressure?
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What mechanism leads to increased contractility of the heart?
What mechanism leads to increased contractility of the heart?
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Which part of the nervous system predominantly causes pupil dilation?
Which part of the nervous system predominantly causes pupil dilation?
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Increased vascular resistance affecting afterload is largely influenced by which factor?
Increased vascular resistance affecting afterload is largely influenced by which factor?
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What physiological response is characterized by salivation, lacrimation, urination, defecation, bronchospasm, and bradycardia?
What physiological response is characterized by salivation, lacrimation, urination, defecation, bronchospasm, and bradycardia?
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What is the significance of a mean arterial pressure (MAP) lower than 60?
What is the significance of a mean arterial pressure (MAP) lower than 60?
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Which of the following is true about the cardiac index (CI)?
Which of the following is true about the cardiac index (CI)?
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If a patient has a stroke volume (SV) of 70 ml and a heart rate (HR) of 90 bpm, what is their cardiac output (QT)?
If a patient has a stroke volume (SV) of 70 ml and a heart rate (HR) of 90 bpm, what is their cardiac output (QT)?
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Which MAP value indicates adequate organ perfusion?
Which MAP value indicates adequate organ perfusion?
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What would be the cardiac index (CI) for a patient with a QT of 5 L/min and a BSA of 2 m2?
What would be the cardiac index (CI) for a patient with a QT of 5 L/min and a BSA of 2 m2?
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Given a patient with a blood pressure of 100/60 mmHg, what is their MAP?
Given a patient with a blood pressure of 100/60 mmHg, what is their MAP?
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Which factor does NOT directly influence the calculation of cardiac output (QT)?
Which factor does NOT directly influence the calculation of cardiac output (QT)?
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How do larger patients affect cardiac index (CI)?
How do larger patients affect cardiac index (CI)?
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If a patient has a QT of 4 L/min and a BSA of 1.5 m2, what is their cardiac index (CI)?
If a patient has a QT of 4 L/min and a BSA of 1.5 m2, what is their cardiac index (CI)?
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What is a potential consequence of low cardiac output (QT)?
What is a potential consequence of low cardiac output (QT)?
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Study Notes
Mean Arterial Pressure (MAP)
- Normal range is 70-105
- Less than 60 indicates inadequate organ perfusion
- Formula: MAP = (2 * Diastolic Blood Pressure) + Systolic Blood Pressure / 3
Cardiac Index (CI)
- Tells if cardiac output (QT) is adequate for patient size
- Larger patients need a higher CI
- Normal range is 2.5-4.0 L/min/m2
- Formula: CI = QT / BSA
Cardiac Output (QT)
- Amount of blood pumped from the left ventricle per minute
- Formula: QT = Stroke Volume (SV) * Heart Rate (HR)
- Normal range is 4-8 L/min at rest
Sympathetic Nervous System
- Releases norepinephrine (NE)
- Increases heart rate and electrical impulses
- Affects all areas of the heart
- Converts glycogen to glucose
- Causes pupil dilation
- "Fight or flight" response
Parasympathetic Nervous System
- Releases acetylcholine (ACh)
- Reduces electrical impulses
- Decreases heart rate
- Affects atrioventricular (AV) nodes
- Causes pupil constriction
- "Rest and digest" response
Factors Affecting Heart Rate
- Increased heart rate: sympathetic activity, anxiety, pain, hypoxia, and vasodilator medications
- Decreased heart rate: parasympathetic activity, beta blockers, and vomiting
Systolic & Diastolic Blood Pressure
- Systole: top number, normal 90-120 mmHg, ventricles contract, semilunar valves open, AV valves close
- Diastole: bottom number, normal 60-90mmHg, ventricles relax, semilunar valves close, AV valves open
Venous System
- Acts as a reservoir for 60% of total blood volume
- Venous return equals cardiac output (QT)
Ejection Fraction (EF)
- Normal range is 65-70%
- Reduced EF (below 50%) indicates reduced cardiac function
- Severely reduced EF (below 30%) leads to severely limited exercise tolerance.
Preload, Afterload, Contractility
- Preload: Ventricular stretch before contraction, influenced by filling, compliance, venous return, and end diastolic volume
- Afterload: Resistance to ventricular emptying, influenced by vascular resistance, ventricular wall tension, and viscosity of blood
- Contractility: Strength of ventricular contraction, impacted by preload
Pulse Pressure (PP)
- Difference between systolic and diastolic blood pressure.
- Normal range is 30-40mmHg.
- A low PP (less than 30mmHg) can indicate low stroke volume
Positive Pressure Ventilation (PPV)
- Augments preload and cardiac output.
- Positive pressure ventilation (PPV) hazards impact preload and contractility, and can have negative effects on blood pressure and urinary output (↓ VR, ↓ BP&QT, Urinary output)
Pulmonary Artery Wedge Pressure (PAWP)
- Measures pressure in the left atrium.
- Normal range is 5-10 mmHg.
Cardiac Work
- Measure of the energy used ejecting blood from the ventricles to overcome arterial pressures.
- Correlates with oxygen needed by the heart
- Higher in the left ventricle.
Key Properties of the Heart Muscle
- Excitability: responding to stimuli
- Inherent rhythmicity: initiating spontaneous electrical impulses
- Conductivity: spreading electrical impulses
- Contractility: responding to electrical impulses with contractions
Layers of the Heart
- Epicardium
- Myocardium (middle layer)
- Endocardium (inner layer lining the heart chambers)
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Description
Explore the fundamentals of cardiovascular physiology, focusing on Mean Arterial Pressure (MAP), Cardiac Index (CI), and Cardiac Output (QT). Understand the roles of the sympathetic and parasympathetic nervous systems in heart function. This quiz will test your knowledge of these critical concepts in human physiology.
