29 Questions
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
What is the primary effect of parasympathetic stimulation on the heart?
Decreases heart rate
Which of the following statements about the autonomic innervation of the heart is NOT correct?
The left stellate ganglion primarily increases heart rate without affecting contractility
Which of the following is a key component of the intermediate (minutes-hours) regulation of arterial pressure?
Renin-angiotensin system
What is the primary location of the CNS vasomotor center?
Medulla and caudal 1/3 of pons
What is the primary effect of sympathetic stimulation on the heart?
Increases heart rate and contractility
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
Which area of the brain plays a key role in modulating the activity of the vasomotor center?
Hypothalamus
What initiates the baroreceptor reflex response via the vagus nerve?
Carotid sinus
Which receptors have the highest concentrations at the carotid bifurcation and aortic arch?
Stretch receptors
What results from activation of the stretch receptors in Levy's baroreceptor reflexes?
Inhibition of the vasoconstrictor center and increased vagal outflow
What is the normal HR response expected during a Valsalva maneuver in autonomic dysfunction testing?
+10 bpm decrease followed by rapid increase above baseline
Which part of the central nervous system is responsible for modulating the activity of the vasoconstrictor area?
Hypothalamus
What is the primary mechanism by which sympathetic stimulation causes vasoconstriction?
Activation of alpha-adrenergic receptors on vascular smooth muscle
Which subtype of the alpha-1 adrenergic receptor is primarily responsible for mediating vasoconstriction?
α1D
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.
Which of the following is NOT a mechanism by which sympathetic stimulation can cause vasoconstriction?
Inhibition of adenylyl cyclase in vascular smooth muscle cells
What is the role of the continuous slow firing of impulses from the vasoconstrictor area?
It maintains a constant level of vascular tone.
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
What is the normal range for the heart rate response to standing ratio?
> 1.21
At which beat after standing is the relative bradycardia most marked?
The 30th beat
What is the normal mean difference in heart rate during deep breathing?
> 15 BPM
How is the blood pressure response to standing measured?
By subtracting the standing blood pressure from the supine blood pressure
What is the primary role of the baroreceptor mechanism?
Maintaining blood pressure within a narrower range
How do chemoreceptors primarily respond to changes?
Increased hydrogen ion concentration
What effect does atrial stretch due to increased blood volume have on renal arterioles?
Reflex dilation
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
In the CNS ischemic response, what occurs when there is a decrease in blood flow to the vasomotor center?
Severe peripheral vasoconstriction
What physiological response does the Valsalva maneuver induce upon forced expiration against a closed glottis?
Baroreflex-induced reduction in heart rate and contractility
This quiz covers the integration of multiple systems involved in the short-term regulation of arterial pressure, including baroreceptor reflexes, chemoreceptor reflexes, and the CNS ischemic response. It also discusses intermediate mechanisms like the renin-angiotensin system and long-term mechanisms such as renal body fluid control.
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