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

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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?

Renin-angiotensin system Signup and view all the answers

What is the primary location of the CNS vasomotor center?

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

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

Increases heart rate and contractility Signup and view all the answers

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

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

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

Hypothalamus Signup and view all the answers

What initiates the baroreceptor reflex response via the vagus nerve?

Carotid sinus Signup and view all the answers

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

Stretch receptors Signup and view all the answers

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

Inhibition of the vasoconstrictor center and increased vagal outflow Signup and view all the answers

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

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

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

Hypothalamus Signup and view all the answers

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

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

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

α1D Signup and view all the answers

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

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

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

Inhibition of adenylyl cyclase in vascular smooth muscle cells Signup and view all the answers

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

It maintains a constant level of vascular tone. Signup and view all the answers

What is the purpose of the Valsalva ratio?

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

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

> 1.21 Signup and view all the answers

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

The 30th beat Signup and view all the answers

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

> 15 BPM Signup and view all the answers

How is the blood pressure response to standing measured?

By subtracting the standing blood pressure from the supine blood pressure Signup and view all the answers

What is the primary role of the baroreceptor mechanism?

Maintaining blood pressure within a narrower range Signup and view all the answers

How do chemoreceptors primarily respond to changes?

Increased hydrogen ion concentration Signup and view all the answers

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

Reflex dilation 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?

Increased heart rate due to direct stretch of SA node 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?

Severe peripheral vasoconstriction Signup and view all the answers

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

Baroreflex-induced reduction in heart rate and contractility Signup and view all the answers