Cardiovascular Physiology Quiz
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Cardiovascular Physiology Quiz

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Questions and Answers

What primary substances does the adrenal medulla release into the blood?

  • Serotonin and histamine
  • Adrenaline and cortisol
  • Acetylcholine and dopamine
  • Norepinephrine and epinephrine (correct)

    • Which adrenergic receptor subtype is responsible for vasodilation in blood vessels during the fight or flight response?

  • β1
  • α2
  • α1
  • β2 (correct)

    • What is the effect of activating α1 adrenoceptors in the arterial system?

  • Vasoconstriction (correct)
  • Decreased heart rate
  • Vasodilation
  • Inhibition of norepinephrine release

    • Which of the following functions does the sympathetic nervous system regulate?

    <p>Stimulating the renin-angiotensin-aldosterone system</p> Signup and view all the answers

    What effect do M2 receptors have on the heart?

    <p>Decrease heart rate and force of contraction</p> Signup and view all the answers

    How do presynaptic α2 receptors function in the autonomic nervous system?

    <p>Inhibit further release of norepinephrine and acetylcholine</p> Signup and view all the answers

    In which areas are β1 adrenoceptors primarily located?

    <p>Juxtaglomerular cells of the kidney and the heart</p> Signup and view all the answers

    What role do the sympathetic nervous system and RAAS play in blood pressure regulation?

    <p>They work together to control blood pressure</p> Signup and view all the answers

    What primarily regulates blood pressure from a systemic hemodynamic perspective?

    <p>Sympathetic nervous system and kidneys</p> Signup and view all the answers

    Which of the following is a common type of hypertension?

    <p>Essential hypertension</p> Signup and view all the answers

    What happens to heart rate when blood pressure is increased?

    <p>The heart rate increases due to reflex tachycardia.</p> Signup and view all the answers

    What is the current definition of hypertension?

    <p>Systolic blood pressure of 130mmHg or more and/or diastolic blood pressure more than 80mmHg</p> Signup and view all the answers

    What commonly associated condition is related to primary hypertension?

    <p>Obesity</p> Signup and view all the answers

    What is the role of the vasomotor center in blood pressure regulation?

    <p>It regulates blood vessel diameter through sympathetic control.</p> Signup and view all the answers

    How do drugs that reduce blood pressure affect reflex responses?

    <p>They cause reflex tachycardia.</p> Signup and view all the answers

    Which factor is NOT typically a cause of secondary hypertension?

    <p>Sedentary lifestyle</p> Signup and view all the answers

    What initiate afferent impulses to the brainstem vasomotor center?

    <p>Baroreceptor activation in response to increased arterial pressure.</p> Signup and view all the answers

    What therapeutic target is considered for effective hypertension management?

    <p>130/80mmHg or lower</p> Signup and view all the answers

    Which of the following substances does NOT typically contribute to blood pressure regulation?

    <p>Hormones from the pancreas</p> Signup and view all the answers

    Which division of the autonomic nervous system decreases after activation of the sympathetic nervous system?

    <p>The parasympathetic nervous system.</p> Signup and view all the answers

    What type of fibers characterize the sympathetic nervous system?

    <p>Short preganglionic and long postganglionic fibers.</p> Signup and view all the answers

    Which medication type is involved in the treatment of hypertension?

    <p>Antihypertensive drugs</p> Signup and view all the answers

    What is a primary effect of the active sympathetic division on vessels and the heart?

    <p>Increase in heart rate and constriction of blood vessels.</p> Signup and view all the answers

    How does the autonomic nervous system influence cardiac smooth muscle?

    <p>Both sympathetic and parasympathetic systems innervate cardiac smooth muscle.</p> Signup and view all the answers

    What is a common disadvantage of α1-blockers related to heart function?

    <p>Increased heart rate and myocardial oxygen requirements</p> Signup and view all the answers

    Which system is often activated by α1-blockers leading to fluid retention?

    <p>Renin-angiotensin-aldosterone system</p> Signup and view all the answers

    How can first dose syncope from α1-blockers be prevented?

    <p>Administering a low dose at bedtime</p> Signup and view all the answers

    Which statement correctly compares the effects of α1-blockers and β1-blockers?

    <p>α1-blockers increase cardiac output while β1-blockers decrease it</p> Signup and view all the answers

    What is a physiological effect of the activation of α1-adrenoceptors?

    <p>Increased peripheral vascular resistance</p> Signup and view all the answers

    Which of the following best describes the difference between prazosin and phentolamine?

    <p>Prazosin does not block α2-adrenoceptors, leading to less tachycardia</p> Signup and view all the answers

    What is a potential side effect of long-term use of α1-blockers?

    <p>Orthostatic hypotension</p> Signup and view all the answers

    Which of the following treatments is commonly prescribed alongside α1-blockers?

    <p>Diuretics</p> Signup and view all the answers

    What is the equation that represents blood pressure?

    <p>BP = CO x PVR</p> Signup and view all the answers

    Which receptors are primarily involved in cardiovascular function?

    <p>β1 and β2 receptors</p> Signup and view all the answers

    What does cardiac output depend on?

    <p>Stroke volume and heart rate</p> Signup and view all the answers

    Which division of the autonomic nervous system increases cardiac function?

    <p>Sympathetic nervous system</p> Signup and view all the answers

    What is primary hypertension characterized by?

    <p>High blood pressure without a known secondary cause</p> Signup and view all the answers

    Which of the following actions is associated with beta blockers?

    <p>Decreasing cardiac output</p> Signup and view all the answers

    What is the main effect of the parasympathetic nervous system on heart function?

    <p>Decreases heart rate</p> Signup and view all the answers

    What relationship exists between cardiac output and blood pressure?

    <p>As cardiac output increases, blood pressure generally increases</p> Signup and view all the answers

    What primarily influences peripheral vascular resistance in blood pressure regulation?

    <p>Sympathetic nervous system activity</p> Signup and view all the answers

    What is considered a secondary cause of hypertension?

    <p>Hyperthyroidism</p> Signup and view all the answers

    Which substance is least likely to contribute to the regulation of blood pressure?

    <p>Bicarbonate</p> Signup and view all the answers

    What is the equation used to express the relationship between blood pressure, cardiac output, and peripheral vascular resistance?

    <p>BP = CO x PVR</p> Signup and view all the answers

    What is the therapeutic target for blood pressure management in patients with hypertension?

    <p>130/80 mmHg or lower</p> Signup and view all the answers

    Which condition is commonly associated with primary hypertension?

    <p>Hypercholesterolemia</p> Signup and view all the answers

    Which receptors are primarily involved in the regulation of cardiac function within the autonomic nervous system?

    <p>β1 and β2 receptors</p> Signup and view all the answers

    What factor is most relevant in determining cardiac output?

    <p>End-diastolic volume (EDV)</p> Signup and view all the answers

    What is the expected cardiac output derived from stroke volume and heart rate?

    <p>CO = SV x HR</p> Signup and view all the answers

    What characterizes the most common form of hypertension?

    <p>Primary or essential hypertension</p> Signup and view all the answers

    Which of the following best describes primary hypertension?

    <p>Has no identified secondary cause</p> Signup and view all the answers

    Which antihypertensive drug mechanism involves targeting the sympathetic nervous system?

    <p>Beta-blockers</p> Signup and view all the answers

    What does the term 'peripheral vascular resistance' refer to in the context of blood pressure?

    <p>The force opposing blood flow in the peripheral circulation</p> Signup and view all the answers

    Which mechanism primarily targets the autonomic nervous system to decrease blood pressure in hypertensive patients?

    <p>Modulating heart rate and vascular tone</p> Signup and view all the answers

    What is the physiological relationship between stroke volume and blood pressure?

    <p>Higher stroke volume can increase blood pressure</p> Signup and view all the answers

    What effect does the sympathetic nervous system usually have on cardiac function?

    <p>It increases heart rate and contractility</p> Signup and view all the answers

    What occurs when blood pressure is too high?

    <p>Baroreceptors in the aortic arch and carotid sinus are activated.</p> Signup and view all the answers

    What is a primary result of vagal stimulation from the brainstem vasomotor center?

    <p>Decreased heart rate.</p> Signup and view all the answers

    How does the body respond to a sudden drop in arterial pressure when standing?

    <p>Baroreceptor firing decreases initially but adapts over time.</p> Signup and view all the answers

    What happens to sympathetic stimulation when blood pressure is reduced?

    <p>It is reduced, decreasing heart rate and vascular resistance.</p> Signup and view all the answers

    What long-term mechanism is necessary to maintain normal blood pressure?

    <p>Activation of hormonal and renal mechanisms.</p> Signup and view all the answers

    Which of the following correctly describes baroreceptor adaptation?

    <p>After a decrease in pressure, baroreceptors quickly return to normal firing.</p> Signup and view all the answers

    What effect do drugs that increase blood pressure have on heart rhythm?

    <p>They produce reflex bradycardia.</p> Signup and view all the answers

    What immediate physiological response is triggered by high arterial pressure?

    <p>Activation of the vagal motor nucleus.</p> Signup and view all the answers

    How do β-blockers primarily lower blood pressure?

    <p>By blocking β1 receptors in the heart and kidneys</p> Signup and view all the answers

    What is a potential consequence of using α1 receptor antagonists?

    <p>Orthostatic hypotension due to vasodilation</p> Signup and view all the answers

    Which of the following describes a mechanism through which diuretics lower blood pressure?

    <p>Promote sodium excretion and reduce blood volume</p> Signup and view all the answers

    What effect do β-blockers have on the renin-angiotensin-aldosterone system (RAAS)?

    <p>Block β1 receptors, leading to decreased renin release</p> Signup and view all the answers

    Which class of antihypertensive drugs primarily reduces peripheral vascular resistance?

    <p>Vasodilators</p> Signup and view all the answers

    What is a common problem associated with α1 receptor antagonists?

    <p>Increased fluid retention</p> Signup and view all the answers

    Which of the following mechanisms does NOT contribute to the blood pressure-lowering effect of centrally acting sympatholytics?

    <p>Increased cardiac output</p> Signup and view all the answers

    Which type of adrenoceptor blockade primarily affects the heart's contractility and rate?

    <p>β1 receptors</p> Signup and view all the answers

    What happens to the heart rate when drugs that reduce blood pressure are administered?

    <p>Heart rate increases due to reflex tachycardia.</p> Signup and view all the answers

    Which mechanism primarily contributes to reflex bradycardia when blood pressure is increased?

    <p>Increased vagal (parasympathetic) outflow.</p> Signup and view all the answers

    How does the autonomic nervous system control cardiac and vascular smooth muscle?

    <p>Through direct innervation by sympathetic and parasympathetic fibers.</p> Signup and view all the answers

    What is the effect of sympathetic nervous system activation on the parasympathetic response?

    <p>It suppresses the parasympathetic response.</p> Signup and view all the answers

    Which of the following describes the general structure of the sympathetic nervous system?

    <p>Short preganglionic and long postganglionic fibers.</p> Signup and view all the answers

    What initiates the afferent impulses to the brainstem vasomotor center?

    <p>Increased arterial pressure activating stretch receptors.</p> Signup and view all the answers

    What is the primary role of the adrenal medulla in autonomic function?

    <p>To release neurotransmitters that stimulate the sympathetic nervous system.</p> Signup and view all the answers

    What is the effect of drugs that increase blood pressure on heart rate?

    <p>They cause reflex tachycardia.</p> Signup and view all the answers

    Study Notes

    Blood Pressure

    • Blood pressure is calculated by multiplying Cardiac Output (CO) by Peripheral Vascular Resistance (PVR).
    • CO is determined by multiplying Stroke Volume (SV) by Heart Rate (HR).
    • SV is the difference between End Diastolic Volume (EDV) and End Systolic Volume (ESV).

    Central Control of Blood Pressure

    • The baroreceptor reflex, located in the aortic arch and carotid sinus, detects changes in arterial pressure.
    • The baroreceptors relay this information via afferent nerves to the brainstem vasomotor center (VMC).
    • The VMC increases vagal outflow to slow the heart rate and reduces sympathetic stimulation of the heart and blood vessels.

    Autonomic Nervous System (ANS) Innervation of the Cardiovascular System

    • The sympathetic and parasympathetic nervous systems innervate cardiac smooth muscle, vascular smooth muscle, and the SA and AV nodes.
    • The adrenal medulla releases norepinephrine (NA) and epinephrine (A) which bind to adrenergic receptors, stimulating the sympathetic nervous system.

    Location and Effects of ANS Receptors on the Cardiovascular System

    • β1 receptors: Located in the heart (SA and AV node, atrial and ventricular muscle) and juxtaglomerular cells of the kidney. Stimulation increases heart rate, force of contraction, automaticity, and activates the renin-angiotensin-aldosterone system.

    • β2 receptors: Located primarily in larger blood vessels in muscles responsible for "fight or flight." Stimulation causes vasodilation.

    • α1 receptors: Located in smooth muscle of blood vessels throughout the arterial system. Stimulation causes vasoconstriction.

    • α2 receptors: Located on presynaptic neurons. Stimulation inhibits the further release of NA and ACh.

    • M2 receptors: Located in the heart (SA and AV node and atrial muscle). Stimulation reduces heart rate, force of contraction, and can cause AV block.

    Systemic Control of Blood Pressure

    • The sympathetic nervous system and the kidneys are the primary regulators of blood pressure.
    • The sympathetic nervous system affects cardiac output and peripheral vascular resistance.
    • Vasoactive substances within the blood vessel wall also contribute to blood pressure regulation.

    Hypertension (HTN)

    • HTN is diagnosed with a systolic blood pressure (SBP) of 130 mmHg or more, and/or diastolic blood pressure (DBP) of 80 mmHg or more.
    • Treatment for HTN is typically initiated with persistent BP readings of 140/90 mmHg or more, aiming for a target < 130/80 mmHg.

    Types of HTN

    • Primary/Idiopathic/Essential hypertension is the most common type and is associated with other lifestyle illnesses such as diabetes, obesity, and hypercholesterolemia.
    • Secondary hypertension is caused by underlying medical conditions such as kidney failure (acute or chronic), renovascular disease, adrenal disorders, thyroid disease (hyperthyroidism), and parathyroid disease (hyperparathyroidism).
    • Other causes include alcohol and recreational drugs, medications such as sex hormones, corticosteroids, and NSAIDs, and pregnancy-induced hypertension and pre-eclampsia/eclampsia.

    Alpha-blockers

    • Alpha-blockers (α1-blockers) reduce peripheral vascular resistance by blocking α1-adrenergic receptors.
    • α1-blockers can cause reflex sympathetic activation and increase heart rate, contractile force, and circulating norepinephrine levels, potentially increasing myocardial oxygen demand.
    • α1-blockers may cause orthostatic hypotension and "first dose" syncope, especially when administered with diuretics.
    • Prazosin, a selective α1-blocker, causes less tachycardia than phentolamine as it does not block α2-mediated inhibition of NA release.

    Blood Pressure

    • Blood pressure (BP) is determined by cardiac output (CO) and peripheral vascular resistance (PVR).
    • CO is determined by stroke volume (SV) and heart rate (HR).
    • Increases in either CO or PVR lead to increased BP.

    Autonomic Nervous System (ANS)

    • The ANS regulates blood pressure by controlling heart rate, contractility, and vascular tone.
    • The sympathetic nervous system (SNS) increases CO and PVR, leading to increased BP.
    • The parasympathetic nervous system (PNS) decreases CO and PVR, leading to decreased BP.

    Baroreceptor Reflex

    • The baroreceptor reflex is a negative feedback mechanism that helps regulate blood pressure.
    • Baroreceptors are located in the aortic arch and carotid sinus.
    • When BP increases, baroreceptors send signals to the brainstem, which activates the PNS and inhibits the SNS, leading to decreased BP.

    Innervation of the Cardiovascular System by the ANS

    • Both the SNS and PNS directly innervate cardiac smooth muscle, vascular smooth muscle, and the SA and AV nodes.
    • The SNS also innervates the adrenal medulla, causing the release of norepinephrine and adrenaline, which further stimulate the SNS.

    Hypertension (HTN)

    • HTN is defined as a systolic blood pressure of 130mmHg or more and/or diastolic blood pressure of 80mmHg or more.
    • HTN is classified as primary or secondary.
    • Primary HTN is the most common type and has multiple causes, including lifestyle factors.
    • Secondary HTN is caused by underlying medical conditions, such as kidney disease or adrenal disorders.

    Treatment of HTN

    • Persistent BP readings of 140/90mmHg or more require treatment.
    • The therapeutic target for BP is usually less than 130/80mmHg.
    • Treatment options include lifestyle modifications and medications.

    Mechanism of Action: Beta-Blockers

    • Beta-blockers block β1 receptors in the heart and kidney, reducing BP.
    • Blocking β1 receptors in the heart reduces heart rate and contractility, decreasing CO.
    • Blocking β1 receptors in the kidney reduces renin release, inhibiting the RAAS and decreasing BP.

    Mechanism of Action: Alpha-Blockers

    • Alpha-blockers block α1 receptors, causing vasodilation and decreasing PVR, which reduces BP.
    • Alpha-blockers can cause adverse effects like orthostatic hypotension and reflex tachycardia.
    • They are not typically used as first-line therapy for HTN.

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    Description

    Test your understanding of blood pressure and its regulation through the cardiovascular system. This quiz covers topics such as cardiac output, the baroreceptor reflex, and the role of the autonomic nervous system. Challenge yourself with questions that dive deep into these physiological mechanisms.

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