A pharmacology student is asked which vascular segment lacks direct sympathetic innervation in the classic teaching model. Which is the best answer?

A. Veins
B. Capillaries
C. Arterioles
D. Small arteries

B. Capillaries

Sympathetic stimulation of the heart produces which combination?

A. ↓ heart rate, ↓ contractility
B. ↑ heart rate, ↑ contractility
C. ↑ heart rate, ↓ contractility
D. ↓ heart rate, ↑ contractility

B. ↑ heart rate, ↑ contractility

The vasomotor system is primarily located in the:

A. lower pons and medulla
B. upper midbrain and medulla
C. posterior hypothalamus and medulla
D. cervical spinal cord and medulla

A. lower pons and medulla

Which area of the vasomotor system is located in the anterolateral lower half of the medulla and projects upward to inhibit another area?

A. Sensory area
B. Cardioacceleratory area
C. Vasodilator area
D. Vasoconstrictor area

C. Vasodilator area

Which vasomotor area is located bilaterally in the anterolateral upper medulla and sends output through the spinal cord to excite preganglionic sympathetic neurons?

A. Sensory area
B. Vasoconstrictor area
C. Dorsal motor area
D. Vasodilator area

B. Vasoconstrictor area

The sensory area of the vasomotor system is located mainly in the:

A. nucleus ambiguus
B. dorsal motor nucleus
C. nucleus tractus solitarius
D. intermediolateral column

C. nucleus tractus solitarius

Which cranial nerves provide major afferent input to the nucleus tractus solitarius for cardiovascular reflexes?

A. CN V and CN VII
B. CN VII and CN IX
C. CN VIII and CN X
D. CN IX and CN X

D. CN IX and CN X

The baroreceptor reflex from the carotid sinus and aortic arch primarily engages which vasomotor area first?

A. Vasodilator area
B. Lateral cardiac area
C. Sensory area
D. Vasoconstrictor area

C. Sensory area

A baseline partial constriction of blood vessels maintained by sympathetic discharge from the vasomotor center is called:

A. vascular recoil
B. vasomotor tone
C. myogenic tone
D. basal resistance

B. vasomotor tone

This baseline sympathetic vasoconstrictor tone is most important for maintaining:

A. capillary permeability
B. heart block prevention
C. regular blood pressure
D. coronary autoregulation

C. regular blood pressure

Which portion of the vasomotor center mainly controls sympathetic output to the heart, increasing heart rate and contractility?

A. lateral portion
B. inferior portion
C. medial portion
D. posterior portion

A. lateral portion

The medial portions of the vasomotor center mainly influence the heart by signaling adjacent dorsal motor nuclei of the vagus to:

A. increase venous tone
B. raise contractility
C. slow the heart
D. increase afterload

C. slow the heart

Which higher brain regions can influence the vasomotor system?

A. Thalamus, mesencephalon, diencephalon
B. Reticular pons, mesencephalon, diencephalon
C. Cerebellum, mesencephalon, diencephalon
D. Basal ganglia, mesencephalon, diencephalon

B. Reticular pons, mesencephalon, diencephalon

In the reticular pons, mesencephalon, and diencephalon, which neurons usually excite the vasomotor system?

A. medial and inferior
B. medial and superior
C. lateral and inferior
D. lateral and superior

D. lateral and superior

In the reticular pons, mesencephalon, and diencephalon, which neurons usually inhibit the vasomotor system?

A. lateral and inferior
B. medial and inferior
C. medial and superior
D. lateral and superior

B. medial and inferior

Stimulation of the posterolateral hypothalamus has what overall effect on the vasomotor center?

A. mainly excitation
B. mainly inhibition
C. no major effect
D. only vagal activation

A. mainly excitation

The anterior hypothalamus can produce what effect on the vasomotor center?

A. excitation only
B. inhibition only
C. excitation or inhibition
D. no direct effect

C. excitation or inhibition

The principal brain region involved in controlling the CNS vasodilator system is the:

A. posterior hypothalamus
B. anterior hypothalamus
C. upper midbrain
D. lower cerebellum

B. anterior hypothalamus

The cerebral motor cortex has what predominant effect on the vasomotor center?

A. inhibitory
B. biphasic
C. excitatory
D. negligible

C. excitatory

Which neurotransmitter is the main sympathetic vasoconstrictor transmitter acting directly on alpha-adrenergic receptors of vascular smooth muscle?

A. epinephrine
B. acetylcholine
C. dopamine
D. norepinephrine

D. norepinephrine

A person faints after emotional distress. They first become pale and bradycardic, then briefly lose consciousness from reduced cerebral perfusion. Which mechanism best explains this event?

A. hypertensive emergency
B. vasovagal syncope
C. carotid dissection
D. neurogenic diabetes insipidus

B. vasovagal syncope

In vasovagal syncope, the immediate hemodynamic collapse is produced by activation of the muscle vasodilator system together with:

A. strong parasympathetic slowing
B. strong sympathetic tachycardia
C. marked angiotensin release
D. intense arteriolar constriction

A. strong parasympathetic slowing

Which statement about circulating catecholamines released during sympathetic activation is most accurate?

A. Epinephrine always constricts more
B. Norepinephrine always dilates muscle
C. Epinephrine may dilate some beds
D. Norepinephrine prefers beta receptors

C. Epinephrine may dilate some beds

Which combination best reflects the 3 major sympathetic changes that raise arterial pressure?

A. Arteriolar dilation, bradycardia, venodilation
B. Venodilation, less contractility, tachycardia
C. Arteriolar constriction, venoconstriction, heart stimulation
D. Capillary dilation, venoconstriction, bradycardia

C. Arteriolar constriction, venoconstriction, heart stimulation

A patient stands up quickly and briefly feels lightheaded. Which mechanism provides the most rapid physiologic regulation of arterial pressure?

A. Nervous control
B. Renal sodium excretion
C. Aldosterone release
D. Angiogenesis

A. Nervous control

A hiker suddenly encounters a bear and experiences an immediate rise in arterial pressure that helps prepare for flight. This response is called:

A. Volume reflex
B. Chemoreceptor reflex
C. Cushing reaction
D. Alarm reaction

D. Alarm reaction

Which structure is best described as a spray-type nerve ending in large arterial walls that senses stretch and feeds back to autonomic centers?

A. Low-pressure receptor
B. Baroreceptor
C. Chemoreceptor
D. Nociceptor

B. Baroreceptor

Which pairing of major baroreceptor location and afferent nerve is correct?

A. Carotid sinus — CN IX
B. Carotid sinus — CN X
C. Aortic arch — CN IX
D. Aortic arch — CN XII

A. Carotid sinus — CN IX

Which pairing of major baroreceptor location and afferent nerve is correct?

A. Carotid body — CN IX
B. Aortic body — CN IX
C. Aortic arch — CN X
D. Pulmonary artery — CN X

C. Aortic arch — CN X

Hering’s nerve is most closely associated with which receptor site?

A. Aortic arch baroreceptor
B. Pulmonary stretch receptor
C. Aortic body chemoreceptor
D. Carotid sinus baroreceptor

D. Carotid sinus baroreceptor

The carotid sinus baroreceptor is located in the wall of the:

A. Common carotid origin
B. Internal carotid above bifurcation
C. External carotid bifurcation
D. Subclavian artery origin

B. Internal carotid above bifurcation

Baroreceptors respond most effectively to:

A. Chronic stable pressure
B. Slowly falling pressure
C. Rapid pressure changes
D. Mean venous pressure

C. Rapid pressure changes

A sudden increase in arterial pressure stretches baroreceptors. What is the immediate autonomic response?

A. Vagal excitation, vasoconstrictor inhibition
B. Vagal inhibition, vasoconstrictor excitation
C. Sympathetic excitation, vagal inhibition
D. Chemoreceptor activation, ADH release

A. Vagal excitation, vasoconstrictor inhibition

Increased baroreceptor firing lowers cardiac output primarily by causing:

A. More preload and tachycardia
B. Less vagal tone only
C. More contractility and afterload
D. Lower heart rate and contractility

D. Lower heart rate and contractility

Baroreceptors are most important for which type of blood pressure regulation?

A. Long-term regulation
B. Endocrine regulation
C. Short-term regulation
D. Volume-independent control

C. Short-term regulation

Baroreceptors are less effective as chronic controllers of arterial pressure mainly because they:

A. Require intact kidneys
B. Signal only below 80 mmHg
C. Function only during sleep
D. Reset to prevailing pressure

D. Reset to prevailing pressure

Chemoreceptors are most sensitive to which stimulus pattern?

A. Low O2, high CO2/H+
B. High O2, low CO2/H+
C. High Na+, low volume
D. Low K+, high glucose

A. Low O2, high CO2/H+

Arterial chemoreceptors help raise blood pressure primarily by exciting the:

A. Vagal nuclei
B. Vasomotor area
C. Renal cortex
D. Atrial myocardium

B. Vasomotor area

Chemoreceptor afferent fibers travel mainly through which nerves?

A. Hypoglossal and vagus
B. Trigeminal and vagus
C. Glossopharyngeal and hypoglossal
D. Hering’s and vagus nerves

D. Hering’s and vagus nerves

Which statement about arterial pressure and chemoreceptors is most accurate?

A. Low pressure cannot affect them
B. High pressure activates them directly
C. Low pressure may activate them indirectly
D. They sense stretch and not gases

C. Low pressure may activate them indirectly

If arterial pressure drops very low, blood flow through the carotid and aortic bodies decreases. That sluggish flow lets CO₂ and H⁺ build up and O₂ fall locally, so the chemoreceptors become activated indirectly.

Chemoreceptors become especially important as blood pressure controllers when mean arterial pressure falls below about:

A. 120 mmHg
B. 100 mmHg
C. 80 mmHg
D. 60 mmHg

C. 80 mmHg

Which set correctly identifies the major peripheral chemoreceptor organs?

A. Carotid bodies and aortic bodies
B. Carotid sinus and atria
C. Aortic arch and ventricles
D. Pulmonary artery and medulla

A. Carotid bodies and aortic bodies

Which statement best describes low-pressure receptors?

A. They monitor systemic arterial pressure
B. They are stretch receptors in atria
C. They are carotid sinus endings
D. They sense oxygen tension mostly

B. They are stretch receptors in atria

Low-pressure receptors are especially important for minimizing arterial pressure changes caused by shifts in:

A. Vascular compliance
B. Blood volume
C. Plasma sodium
D. Tissue oxygen use

B. Blood volume

Atrial stretch triggers reflex dilation of renal afferent arterioles and decreases hypothalamic ADH output. This overall response is called the:

A. Alarm reaction
B. Baroreceptor reflex
C. Chemoreceptor reflex
D. Volume reflex

D. Volume reflex

Which additional hormone may be released with atrial stretch as part of the volume reflex?

A. Aldosterone
B. Angiotensin II
C. ANP
D. Renin

C. ANP

A patient receives a rapid saline infusion. Stretch of the atria leads to reflex tachycardia that helps prevent venous pooling. Which reflex best explains this?

A. Cushing reflex
B. Bainbridge reflex
C. Baroreceptor reflex
D. CNS ischemic response

B. Bainbridge reflex

Rapid saline infusion → ↑ venous return → ↑ atrial stretch

Atrial stretch receptors then signal the brain to increase heart rate. It helps move the extra venous return forward and prevents blood from pooling in the veins.

The Bainbridge reflex helps prevent damming of blood primarily in the:

A. Coronaries and liver
B. Brain and kidneys
C. Skin, muscle, and lungs
D. Veins, atria, and lungs

D. Veins, atria, and lungs

In the Bainbridge reflex, increased atrial filling increases heart rate partly because stretch directly affects the:

A. SA node
B. AV node
C. Carotid sinus
D. Aortic arch

A. SA node

Atrial stretch triggers afferent signaling to the medulla mainly through the:

A. Glossopharyngeal nerve
B. Phrenic nerve
C. Vagus nerve
D. Sympathetic chain

C. Vagus nerve

A patient with sudden severe cerebral hypoperfusion develops a massive sympathetic discharge. The trigger is ischemia of the:

A. Carotid body
B. Lower brainstem vasomotor center
C. Aortic arch receptors
D. Adrenal medulla

B. Lower brainstem vasomotor center

Marked reduction of blood flow to the vasomotor center causes direct excitation of which neurons?

A. Cardioinhibitory neurons
B. Dorsal vagal neurons
C. Nucleus solitarius neurons
D. Cardioaccelerator neurons

D. Cardioaccelerator neurons

The CNS ischemic response is most accurately described as:

A. Mild vagal bradycardia
B. Venous pooling from ischemia
C. Arterial pressure rise from cerebral ischemia
D. Renal vasodilation during hypotension

C. Arterial pressure rise from cerebral ischemia

Why is the CNS ischemic response considered an emergency control system?

A. It lowers CSF pressure
B. It acts rapidly and powerfully
C. It resets in days
D. It needs kidney hormones

B. It acts rapidly and powerfully

A patient with very high intracranial pressure develops severe hypertension and a brainstem ischemic response. This is the:

A. Cushing reaction
B. Bainbridge reflex
C. Chemoreceptor reflex
D. Alarm reaction

A. Cushing reaction

In the Cushing reaction, rising CSF pressure eventually compromises cerebral blood flow mainly by:

A. Dilating cerebral veins
B. Lowering venous return
C. Stimulating aortic baroreceptors
D. Compressing cerebral arteries

D. Compressing cerebral arteries

The Cushing reaction primarily protects the brain by preserving perfusion to:

A. Skeletal muscles
B. Pulmonary vessels
C. Vital brain centers
D. Renal cortex

C. Vital brain centers

Among nervous mechanisms controlling circulation, the most rapidly acting is the:

A. Endocrine system
B. Autonomic nervous system
C. Renal-pressure system
D. Angiogenic response

B. Autonomic nervous system

During strong baroreceptor or chemoreceptor activation, signals to abdominal skeletal muscle can increase venous return by causing:

A. Abdominal compression reflex
B. Reactive hyperemia
C. Active hyperemia
D. Mayer oscillation

A. Abdominal compression reflex

The abdominal compression reflex raises arterial pressure mainly by:

A. Reducing renal filtration
B. Increasing arteriolar resistance
C. Slowing the sinus node
D. Increasing cardiac output

D. Increasing cardiac output

During normal respiration, arterial pressure usually:

A. Falls only in expiration
B. Remains fixed each cycle
C. Rises early in expiration
D. Peaks during inspiration

C. Rises early in expiration

Respiratory waves in arterial pressure can result from medullary respiratory signals:

A. Bypassing the medulla
B. Spilling into vasomotor centers
C. Activating only vagal nuclei
D. Blocking sympathetic output

B. Spilling into vasomotor centers

Simple idea:

Breathing signals can influence blood vessel tone, causing arterial pressure to rise and fall with respiration.

Another contributor to respiratory waves is the negative intrathoracic pressure of inspiration, which tends to:

A. Raise cardiac output immediately
B. Raise systemic resistance
C. Increase CSF pressure
D. Reduce cardiac output

D. Reduce cardiac output

↓ intrathoracic pressure
→ more blood is pulled into the right heart
→ pulmonary vessels temporarily hold more blood
→ less blood reaches the left heart for a moment
→ ↓ left ventricular output
→ slight ↓ arterial pressure

Large oscillatory arterial pressure waves recorded over time are called:

A. Vasomotor or Mayer waves
B. Cushing oscillations
C. Bainbridge fluctuations
D. Volume-reflex waves

A. Vasomotor or Mayer waves

Vasomotor/Mayer waves are caused mainly by oscillation of the:

A. Volume reflex
B. Bainbridge reflex
C. Baroreceptor reflex
D. Abdominal compression reflex

C. Baroreceptor reflex

Chemoreceptor reflexes contribute more strongly to Mayer-wave generation when arterial pressure is in which range?

A. 120–160 mmHg
B. 90–120 mmHg
C. 0–20 mmHg
D. 40–80 mmHg

D. 40–80 mmHg

Neurons from the vasoconstrictor area primarily act by:

A. Inhibiting vagal nuclei
B. Exciting sympathetic preganglionics
C. Stimulating adrenal cortex
D. Dilating precapillary sphincters

B. Exciting sympathetic preganglionics

Fibers from the vasodilator area produce vasodilation mainly by:

A. Activating vagal efferents
B. Stimulating adrenal medulla
C. Inhibiting vasoconstrictor area
D. Blocking baroreceptor input

C. Inhibiting vasoconstrictor area

Which reflex is the classic example of sensory-area input controlling arterial pressure?

A. Bainbridge reflex
B. Baroreceptor reflex
C. Cushing reflex
D. Chemoreceptor reflex

B. Baroreceptor reflex

The medial portion lowers heart pumping by signaling adjacent dorsal ______ nuclei of the vagus.

A. Sensory
B. Salivatory
C. Motor
D. Ambiguus

C. Motor

Which hypothalamic region mainly excites the vasomotor center?

A. Anterior hypothalamus
B. Medial hypothalamus
C. Posterolateral hypothalamus
D. Supraoptic nucleus

C. Posterolateral hypothalamus

Which hypothalamic region can produce either mild excitation or inhibition of the vasomotor center?

A. Posterior hypothalamus
B. Anterior hypothalamus
C. Lateral hypothalamus
D. Mammillary body

B. Anterior hypothalamus

Which higher center is specifically listed as able to excite or inhibit the vasomotor center?

A. Cerebellar vermis
B. Septum
C. Caudate nucleus
D. Pineal gland

B. Septum

A patient faints during intense emotional distress. The mechanism involves muscle vasodilation plus strong vagal signaling that markedly ______ the heart.

A. Stiffens
B. Enlarges
C. Slows
D. Blocks

C. Slows

In vasovagal syncope, the immediate loss of consciousness results because ______ pressure falls rapidly.

A. Venous
B. Portal
C. Capillary
D. Arterial

D. Arterial

Constriction of most systemic arterioles raises arterial pressure mainly by increasing:

A. Venous return
B. Pulse pressure
C. Total peripheral resistance
D. Blood viscosity

C. Total peripheral resistance

During a generalized sympathetic pressor response, the veins are especially:

A. Dilated
B. Constricted
C. Atonic
D. Unchanged

B. Constricted

During an acute massive sympathetic discharge, the heart can pump approximately how much more blood than normal?

A. 25% more
B. 50% more
C. Twofold more
D. Fourfold more

C. Twofold more

In heavy exercise, arterial pressure typically rises by about:

A. 30 to 40%
B. 5 to 10%
C. 60 to 70%
D. 100%

A. 30 to 40%

Baroreceptors are best described as:

A. Chemosensitive glomus cells
B. Spray-type stretch endings
C. Venous pressure sensors
D. Endocrine vascular cells

B. Spray-type stretch endings

Which additional site contains major arterial baroreceptors?

A. Pulmonary trunk
B. Common iliac artery
C. Aortic arch wall
D. Left ventricle apex

C. Aortic arch wall

Signals from carotid sinus baroreceptors travel first through:

A. Vagus fibers
B. Sympathetic chain
C. Phrenic fibers
D. Hering’s nerves

D. Hering’s nerves

After passing through Hering’s nerves, carotid baroreceptor afferents enter which cranial nerve?

A. CN X
B. CN IX
C. CN VII
D. CN V

B. CN IX

Both carotid and aortic baroreceptor afferents ultimately project to the:

A. Nucleus tractus solitarius
B. Dorsal motor nucleus
C. Nucleus ambiguus
D. Reticular activating system

A. Nucleus tractus solitarius

Aortic arch baroreceptor signals reach the medulla through the:

A. Glossopharyngeal nerves
B. Hering’s nerves
C. Hypoglossal nerves
D. Vagus nerves

D. Vagus nerves

Once baroreceptor input reaches the nucleus tractus solitarius, the next central response includes inhibition of the medullary:

A. Vasodilator center
B. Respiratory center
C. Sensory relay nuclei
D. Vasoconstrictor center

D. Vasoconstrictor center

At the same time, baroreceptor activation excites the:

A. Sympathetic cardiac center
B. Vagal parasympathetic center
C. Adrenal medulla directly
D. Somatic motor cortex

B. Vagal parasympathetic center

Strong activation of arterial baroreceptors by high pressure reflexly causes arterial pressure to:

A. Rise sharply
B. Stay unchanged
C. Decrease
D. Oscillate only

C. Decrease

The reflex fall in arterial pressure during baroreceptor activation occurs through reduced peripheral resistance and reduced:

A. Cardiac output
B. Venous oxygen content
C. CSF pressure
D. Pulmonary compliance

A. Cardiac output

Immediately after standing, arterial pressure in the head and upper body tends to:

A. Rise abruptly
B. Remain unchanged
C. Equal venous pressure
D. Fall

D. Fall

Because baroreceptors oppose both rises and falls in arterial pressure, they are called the:

A. Volume reservoir system
B. Pressure buffer system
C. Chemoreceptor alarm system
D. Last-ditch mechanism

B. Pressure buffer system

The nerves from the arterial baroreceptors are also called:

A. Pressor nerves
B. Stretch nerves
C. Buffer nerves
D. Nutrient nerves

C. Buffer nerves

Each carotid or aortic body receives abundant blood flow through a small:

A. Portal artery
B. Collateral artery
C. Sinusoidal channel
D. Nutrient artery

D. Nutrient artery

When arterial pressure falls severely, chemoreceptors become stimulated mainly because local blood flow falls, causing low oxygen plus excess:

A. Calcium and sodium
B. Carbon dioxide and hydrogen
C. Glucose and lactate
D. Chloride and bicarbonate

B. Carbon dioxide and hydrogen

Chemoreceptor signals raise arterial pressure primarily by exciting the:

A. Vagal center
B. Nucleus ambiguus
C. Vasomotor center
D. Low-pressure receptors

C. Vasomotor center

Stretch receptors located in the atria and pulmonary arteries are called:

A. Baroreceptors
B. Low-pressure receptors
C. Chemoreceptors
D. Osmoreceptors

B. Low-pressure receptors

A rapid saline infusion increases atrial filling. Which renal vascular response is part of the reflex that helps reduce the expanded blood volume?

A. Efferent arteriolar constriction
B. Afferent arteriolar dilation
C. Renal venous constriction
D. Mesangial contraction

B. Afferent arteriolar dilation

Stretch of the atria promotes renal fluid loss primarily by increasing glomerular filtration and:

A. increasing tubular secretion
B. decreasing renal perfusion
C. decreasing tubular reabsorption
D. increasing aldosterone release

C. decreasing tubular reabsorption

Severe reduction in blood flow to the lower brainstem vasomotor center directly excites which neurons?

A. vasodilator and cardioinhibitory
B. sensory and vagal
C. vasoconstrictor and cardioaccelerator
D. baroreceptor and chemoreceptor

C. vasoconstrictor and cardioaccelerator

Marked arterial pressure elevation caused by cerebral ischemia is termed the:

A. Bainbridge reflex
B. CNS ischemic response
C. volume reflex
D. alarm reaction

B. CNS ischemic response

During intense cerebral ischemia, sympathetic vasoconstriction may become so extreme that peripheral vessels are nearly:

A. denervated
B. dilated
C. thrombosed
D. occluded

D. occluded

The CNS ischemic response is one of the most powerful activators of the:

A. vagal cardioinhibitory system
B. renin-angiotensin system
C. sympathetic vasoconstrictor system
D. low-pressure receptor system

C. sympathetic vasoconstrictor system

The CNS ischemic response usually does not become significant until mean arterial pressure falls to about:

A. 100 mmHg
B. 80 mmHg
C. 60 mmHg
D. 40 mmHg

C. 60 mmHg

The Cushing reaction primarily protects the brain by preserving perfusion to its:

A. cortical association areas
B. visual cortex
C. vital centers
D. cerebellar hemispheres

C. vital centers

When strong baroreceptor or chemoreceptor reflexes are activated, somatic motor output is sent especially to the:

A. intercostal muscles
B. abdominal muscles
C. facial muscles
D. calf muscles

B. abdominal muscles

In the abdominal compression reflex, contraction of these muscles shifts blood from abdominal venous reservoirs toward the:

A. lungs
B. kidneys
C. brain
D. heart

D. heart

One cause of respiratory waves is that medullary breathing signals “spill over” into the:

A. nucleus ambiguus
B. vasomotor center
C. cerebellar vermis
D. hypothalamic nuclei

B. vasomotor center

During inspiration, thoracic pressure becomes more negative, causing intrathoracic blood vessels to:

A. collapse
B. constrict
C. thrombose
D. expand

D. expand

Respiratory pressure changes in thoracic vessels can excite both vascular and ______ stretch receptors.

A. carotid
B. aortic
C. atrial
D. ventricular

C. atrial

Large oscillatory arterial pressure waves superimposed on smaller respiratory waves are called:

A. Cushing waves
B. Korotkoff waves
C. Bainbridge waves
D. Mayer waves

D. Mayer waves