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Questions and Answers
What is the pressure in the pulmonary artery during systole?
What is the pressure in the pulmonary artery during systole?
Which of the following statements is true about baroreceptors?
Which of the following statements is true about baroreceptors?
Where is the best site to measure mixed venous PO2?
Where is the best site to measure mixed venous PO2?
What percentage of ventricular filling is contributed by atrial contraction?
What percentage of ventricular filling is contributed by atrial contraction?
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What is the lowest intrinsic discharge activity among cardiac conduction tissues?
What is the lowest intrinsic discharge activity among cardiac conduction tissues?
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With a mixed venous oxygen content of 110 ml/L and an arterial oxygen content of 150 ml/L and an oxygen uptake of 280 ml/min, what is the cardiac output?
With a mixed venous oxygen content of 110 ml/L and an arterial oxygen content of 150 ml/L and an oxygen uptake of 280 ml/min, what is the cardiac output?
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Where is the greatest volume of blood found in the body?
Where is the greatest volume of blood found in the body?
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What pressure in the right ventricle is approximately when the pulmonary valve closes?
What pressure in the right ventricle is approximately when the pulmonary valve closes?
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What primarily causes the long refractory period in cardiac muscle?
What primarily causes the long refractory period in cardiac muscle?
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What is the primary advantage of the Starling mechanism in the heart?
What is the primary advantage of the Starling mechanism in the heart?
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What is the result of baroreceptor stimulation?
What is the result of baroreceptor stimulation?
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An increase in arterial pulse pressure is likely to be associated with which of the following?
An increase in arterial pulse pressure is likely to be associated with which of the following?
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The fourth heart sound is associated with which event in the cardiac cycle?
The fourth heart sound is associated with which event in the cardiac cycle?
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Frank Starling's law of the heart explains which phenomenon?
Frank Starling's law of the heart explains which phenomenon?
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A decrease in carotid sinus pressure would lead to what change in cardiac output?
A decrease in carotid sinus pressure would lead to what change in cardiac output?
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What does the QRS wave in the ECG represent?
What does the QRS wave in the ECG represent?
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Why does the right ventricle perform less work than the left ventricle?
Why does the right ventricle perform less work than the left ventricle?
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The P wave in an ECG primarily denotes which activity in the heart?
The P wave in an ECG primarily denotes which activity in the heart?
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Which condition is not associated with pure right ventricular failure?
Which condition is not associated with pure right ventricular failure?
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Which vessel is primarily responsible for local regulation of blood flow?
Which vessel is primarily responsible for local regulation of blood flow?
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Which of the following does not increase cardiac output?
Which of the following does not increase cardiac output?
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What effect does stimulation of sympathetic nerves to the heart have?
What effect does stimulation of sympathetic nerves to the heart have?
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Which statement correctly describes heart sounds?
Which statement correctly describes heart sounds?
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Which of the following does not increase heart rate?
Which of the following does not increase heart rate?
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What is a key consequence of stimulating sympathetic beta-1 receptors?
What is a key consequence of stimulating sympathetic beta-1 receptors?
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In a normal ECG, the duration of the PQ interval is typically measured as:
In a normal ECG, the duration of the PQ interval is typically measured as:
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When does ventricular depolarization occur in relation to atrial excitation?
When does ventricular depolarization occur in relation to atrial excitation?
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What characterizes the isovolumetric relaxation phase of the ventricles?
What characterizes the isovolumetric relaxation phase of the ventricles?
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What effect does a loss of one liter of blood have on baroreceptor activity?
What effect does a loss of one liter of blood have on baroreceptor activity?
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In the context of a large infarct affecting the left ventricle, which parameter is likely to increase?
In the context of a large infarct affecting the left ventricle, which parameter is likely to increase?
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Which blood vessels are primarily responsible for the exchange between plasma and interstitial fluid?
Which blood vessels are primarily responsible for the exchange between plasma and interstitial fluid?
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Which cardiac fibers have the slowest conduction velocity for impulses?
Which cardiac fibers have the slowest conduction velocity for impulses?
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What is the effect of stimulating B-1 adrenergic receptors on heart rate?
What is the effect of stimulating B-1 adrenergic receptors on heart rate?
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Which parameter indicates a high preload in the cardiovascular system?
Which parameter indicates a high preload in the cardiovascular system?
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What consequence does aortic valve regurgitation lead to?
What consequence does aortic valve regurgitation lead to?
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Which factor contributes to a decreased stroke volume?
Which factor contributes to a decreased stroke volume?
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What effect does assuming an upright posture have on the cardiovascular system?
What effect does assuming an upright posture have on the cardiovascular system?
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What impact does an infusion of nor-adrenaline have on the cardiovascular system?
What impact does an infusion of nor-adrenaline have on the cardiovascular system?
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Which of these actions results in generalized vasoconstriction?
Which of these actions results in generalized vasoconstriction?
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Which of the following locations are associated with the presence of chemoreceptors?
Which of the following locations are associated with the presence of chemoreceptors?
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Which situation would lead to a decrease in central venous pressure?
Which situation would lead to a decrease in central venous pressure?
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Which factor is least likely to produce local vasodilation?
Which factor is least likely to produce local vasodilation?
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Which of the following factors is least expected to increase cardiac output?
Which of the following factors is least expected to increase cardiac output?
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The Frank-Starling law does not explain which of the following?
The Frank-Starling law does not explain which of the following?
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Which type of drug is likely to increase heart rate from 70 to 100 beats per minute?
Which type of drug is likely to increase heart rate from 70 to 100 beats per minute?
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Excitation of the ventricles occurs in what manner?
Excitation of the ventricles occurs in what manner?
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Which characteristic does not describe AV nodal cells?
Which characteristic does not describe AV nodal cells?
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Study Notes
Cardiovascular System
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Arterial Pressure Reflex: Includes decreased firing of carotid sinus baroreceptors, increased sympathetic activity to the ventricles, and increased parasympathetic activity affecting arterioles in skeletal muscles and skin.
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Hemorrhage Compensation: The correct sequence includes decreased arterial pressure triggering increased baroreceptor firing, leading to increased release of renin by the kidneys. This, in turn, leads to formation of Angiotensin II, followed by decreased excretion of sodium (Na⁺) and water, which prompts the increased production of aldosterone. Ultimately, reduced atrial volume prompts the increase in volume receptor firing rate.
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Venous Return: Venous return is increased by venoconstriction and decreased by deep inspiration. It activates the Bainbridge reflex when increased.
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Heart Nerve Supply: The SA node is innervated by the sympathetic nervous system. Atrial muscle receives both sympathetic and parasympathetic innervation. The right vagus nerve supplies the SA and AV nodes, while the left vagus nerve supplies the SA node. The parasympathetic nervous system supplies ventricular muscle.
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Cardiac Muscle Characteristics: Cardiac muscle is a syncytium, meaning it's interconnected. It has intercalated discs and gap junctions, which contribute to the spread of depolarization. It also contains actin and myosin, the protein components necessary for contraction.
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Pacemaker Prepotential: The pacemaker prepotential is a slow increase in the resting membrane potential, primarily maintained by the opening of long-acting calcium channels. It occurs only in the SA node.
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Parasympathetic Stimulation: Results in increased potassium efflux in cardiac muscles, increasing calcium influx in the SA node, and bradycardia.
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Cardiac Muscle Electrical Activity: Increased extracellular potassium causes depolarization, while repolarization is associated with sodium current. Plateau of the action potential in cardiac muscle is caused by an influx of calcium ions, while the initial repolarization involves delayed potassium efflux.
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Heart Conduction System: The conductive system of the heart does not inherently include the interventricular septum.
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ECG Characteristics: An ECG measures electrical activity and is useful in detecting arrhythmias, with specific waveforms representing different phases of electrical activity in the cardiac cycle. The amplitude indicates the cardiac muscle mass, and the PR-interval represents the strength of the contraction.
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Cardiac Cycle: The cardiac cycle involves ventricular diastole following atrial systole. AV valves close at the beginning of ventricular systole, and the first heart sound signifies the closure of the AV valves. The second heart sound is due to the closure of semilunar valves. Isovolumetric relaxation occurs at the end of diastole.
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Atrial Pressure Wave: The A wave of the atrial pressure wave is directly caused by atrial systole.
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Pulmonary Artery Pressure: Pulmonary artery pressure is lower than pressure in the right ventricle, and less than in the right atrium.
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Chemoreceptors: Located in the aortic arch and carotid sinuses, these monitor arterial blood pressure and are stimulated by abnormal blood gases. Chemoreceptors transmit signals to the vasomotor center, which influences vessel diameter. They are stimulated by hypercapnia (increased CO2).
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Left Ventricular End-Systolic Volume: Resting LV end-systolic volume is about 50 mL.
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Mixed Venous PO2 Measurement: The best location to measure mixed venous PO2 is the pulmonary artery.
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Atrial Contraction Influence on Ventricular Filling: Atrial contraction represents approximately 20-30% of the normal ventricular filling volume.
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Cardiac Output: The cardiac output equals the product of stroke volume and the heart rate. The values can vary based on different conditions.
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Factors Affecting Stroke Volume: Stroke volume increases with increased end-diastolic volume (preload).
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Effects of Increased Stroke Volume: An increased stroke volume can result from an increase in end-diastolic volume or a decrease in end-systolic volume, which can be influenced by factors like sympathetic stimulation or exercise.
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Heart Sounds in the Cardiac Cycle: The first heart sound (S1) is due to closure of the AV valves, and the second heart sound (S2) corresponds to closure of the semilunar valves.
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Noradrenaline Infusion: Noradrenaline infusion leads to an enhanced firing rate of baroreceptors, bradycardia, a reduced peripheral resistance, and myocardial contractility boost, along with an elevated cardiac output.
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Factors Influencing Cardiac Output: Factors affecting cardiac output include heart rate, stroke volume, and venous return.
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Pacemaker Location and Function: The sinoatrial (SA) node is the primary pacemaker because its cells naturally fire/discharge at the fastest rate.
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Cardiovascular Factors: Various factors like blood volume, stroke volume, preload, afterload, and heart rate can affect cardiovascular performance.
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Drugs and Cardiac Function: Some drugs affect cardiac function by interacting with specific receptors, such as adrenergic or cholinergic receptors.
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Coronary Blood Flow: Coronary blood flow, essential for myocardial perfusion, is primarily regulated by sympathetic stimulation, is maximized during diastole, and increases with myocardial metabolism.
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and many more...
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Description
This quiz covers key concepts related to the cardiovascular system, including arterial pressure reflexes, compensation mechanisms for hemorrhage, venous return, and the nerve supply to the heart. Test your understanding of how these components work together to maintain cardiovascular health.
