Short-Term Regulation of Arterial Pressure NRAN 80413 Spring 2024 Ron Anderson, M.D.
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Short-Term Regulation of Arterial Pressure NRAN 80413 Spring 2024 Ron Anderson, M.D.

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Questions and Answers

Which of the following is NOT a key role that the nervous system plays in the control of the cardiovascular system?

  • Regulating long-term changes in blood pressure through renal mechanisms (correct)
  • Redistribution of blood flow to various tissues throughout the body
  • Producing rapid changes in systemic blood pressure
  • Variations in cardiac rate and contractility

    • What is the primary effect of parasympathetic stimulation on the heart?

  • Has little effect on contractility
  • Increases heart rate
  • Decreases heart rate (correct)
  • Increases contractility

    • Which of the following statements about the autonomic innervation of the heart is NOT correct?

  • Parasympathetic fibers have little or no distribution to the ventricles
  • The right stellate ganglion primarily innervates the anterior epicardial surface and interventricular septum
  • Parasympathetic fibers are primarily distributed to the SA node and AV node
  • The left stellate ganglion primarily increases heart rate without affecting contractility (correct)

    • Which of the following is a key component of the intermediate (minutes-hours) regulation of arterial pressure?

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

    What is the primary location of the CNS vasomotor center?

    <p>Medulla and caudal 1/3 of pons</p> Signup and view all the answers

    What is the primary effect of sympathetic stimulation on the heart?

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

    What is the mechanism believed to mediate vasodilation arising from the motor cortex?

    <p>Activation of smooth muscle beta receptors by norepinephrine released from vasodilator fibers</p> Signup and view all the answers

    Which area of the brain plays a key role in modulating the activity of the vasomotor center?

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

    What initiates the baroreceptor reflex response via the vagus nerve?

    <p>Carotid sinus</p> Signup and view all the answers

    Which receptors have the highest concentrations at the carotid bifurcation and aortic arch?

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

    What results from activation of the stretch receptors in Levy's baroreceptor reflexes?

    <p>Inhibition of the vasoconstrictor center and increased vagal outflow</p> Signup and view all the answers

    What is the normal HR response expected during a Valsalva maneuver in autonomic dysfunction testing?

    <p>+10 bpm decrease followed by rapid increase above baseline</p> Signup and view all the answers

    Which part of the central nervous system is responsible for modulating the activity of the vasoconstrictor area?

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

    What is the primary mechanism by which sympathetic stimulation causes vasoconstriction?

    <p>Activation of alpha-adrenergic receptors on vascular smooth muscle</p> Signup and view all the answers

    Which subtype of the alpha-1 adrenergic receptor is primarily responsible for mediating vasoconstriction?

    <p>α1D</p> Signup and view all the answers

    What is the role of the sensory area within the vasomotor center?

    <p>It receives input from cranial nerves IX and X and sends output to the vasoconstrictor and vasodilator areas.</p> Signup and view all the answers

    Which of the following is NOT a mechanism by which sympathetic stimulation can cause vasoconstriction?

    <p>Inhibition of adenylyl cyclase in vascular smooth muscle cells</p> Signup and view all the answers

    What is the role of the continuous slow firing of impulses from the vasoconstrictor area?

    <p>It maintains a constant level of vascular tone.</p> Signup and view all the answers

    What is the purpose of the Valsalva ratio?

    <p>To determine the ratio of the longest R-R interval to the shortest R-R interval during the Valsalva maneuver</p> Signup and view all the answers

    What is the normal range for the heart rate response to standing ratio?

    <p>&gt; 1.21</p> Signup and view all the answers

    At which beat after standing is the relative bradycardia most marked?

    <p>The 30th beat</p> Signup and view all the answers

    What is the normal mean difference in heart rate during deep breathing?

    <p>&gt; 15 BPM</p> Signup and view all the answers

    How is the blood pressure response to standing measured?

    <p>By subtracting the standing blood pressure from the supine blood pressure</p> Signup and view all the answers

    What is the primary role of the baroreceptor mechanism?

    <p>Maintaining blood pressure within a narrower range</p> Signup and view all the answers

    How do chemoreceptors primarily respond to changes?

    <p>Increased hydrogen ion concentration</p> Signup and view all the answers

    What effect does atrial stretch due to increased blood volume have on renal arterioles?

    <p>Reflex dilation</p> Signup and view all the answers

    What is the primary impact of increased right-sided filling pressure on heart rate according to the Bainbridge reflex?

    <p>Increased heart rate due to direct stretch of SA node</p> Signup and view all the answers

    In the CNS ischemic response, what occurs when there is a decrease in blood flow to the vasomotor center?

    <p>Severe peripheral vasoconstriction</p> Signup and view all the answers

    What physiological response does the Valsalva maneuver induce upon forced expiration against a closed glottis?

    <p>Baroreflex-induced reduction in heart rate and contractility</p> Signup and view all the answers

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