Autonomic Nervous System Flashcards
The sympathetic division of the viscerosensory system conveys innocuous information from the viscera.
True or False
False
Explanation
This statement is false: the sympathetic division of the viscerosensory system conveys pain information and the parasympathetic division conveys innocuous sensory information (e.g., stretch/tension in hollow organs contributing to the sense of fullness; blood composition).
Visceral pain is poorly localized and often referred to along a dermatome of the somatic nervous system secondary to “cross talk” between the visceral and somatic sensory systems.
True or False
True
Explanation
This statement is true: visceral pain is poorly localized because of low receptor density and the large receptive fields of viscerosensory neurons, and because there is a small area of the cortex processing visceral sensory information (in comparison to somatosensory information). Sympathetic viscerosensory neurons travel in spinal nerves and often contact somatic dorsal horn cells. This “cross talk” results in visceral pain being interpreted as coming from the dermatome supplied by that spinal cord segment.
The blood vessels of the skin and skeletal muscles of the body wall and limbs are innervated by only the sympathetic division of the ANS.
True or False
True
Explanation
This statement is true: Innervation of structures of the body wall and limbs (i.e., blood vessels supplying skeletal muscles and skin, sweat glands, and the arrector pili muscles) are regulated by the sympathetic system only; smooth muscle, cardiac muscles and glands of the head and body receive dual innervation from both divisions that produce opposing results.
Which of the following statements correctly describes the structural components of the parasympathetic division of the ANS? Select all that apply.
a) Preganglionic neurons are located in cranial visceromotor nuclei & at sacral levels of the spinal cord.
b) Preganglionic neurons are located in the intermediolateral cell column at the levels of T1-L2.
c) Post-ganglionic neurons are located in ganglia in the head region and intramural ganglia.
d) Post-ganglionic neurons are located in the sympathetic chain of ganglia.
e) Acetylcholine is the neurotransmitter that allows communication between the pre and postganglionic neurons, as well as between the postganglionic neurons and the target tissue.
a) Preganglionic neurons are located in cranial visceromotor nuclei & at sacral levels of the spinal cord.
c) Post-ganglionic neurons are located in ganglia in the head region and intramural ganglia.
e) Acetylcholine is the neurotransmitter that allows communication between the pre and postganglionic neurons, as well as between the postganglionic neurons and the target tissue.
Explanation
The preganglionic neurons of the parasympathetic division are found in the cranial visceromotor nuclei (cranial outflow) & S2 – S4 (sacral outflow) spinal segments. The post-ganglionic neurons are located in ganglia in the head region and intramural ganglia (near organs), an the neurotransmitter that allows communication to take place between the neurons and between the neuron and the target tissue is acetylcholine. The preganglionic neurons of the sympathetic division originate in the intermediolateral cell column (T1-L2) and the post-ganglionic neurons are located in the sympathetic chain of ganglia or prevertebral ganglia (near abdominal/pelvic arteries). Acetylcholine is the neurotransmitter that allows communication between the neurons and norepinephrine is the transmitter that allows communication between the post-ganglionic cell and the target tissue.
Your patient sustained a neck injury that damaged the right superior cervical ganglion. You anticipate seeing which of the following clinical signs. Select all that apply.
left facial flushing
right facial flushing
right ptosis
right pupil constriction
left anhidrosis
right facial flushing
right ptosis
right pupil constriction
Explanation
Damage to the right superior cervical ganglion reduces sympthateic outflow to the structures of the head/face: this will result in an ipsilateral Horner syndrome: right pupillary constriction (unopposed parasympathetic outflow), right ptosis (weak/paralyzed superior tarsal muscle); right facial flushing (loss of vascular tone); and absence of sweating on the right side (loss of innervation of sweat glands).
Which of the following statements best describes the micturition reflex?
Decreased firing rate of the sensory afferents of the bladder wall results in increased parasympathetic outflow, increased sympathetic outflow, and inhibition of the somatic motor neurons resulting in bladder voiding.
Increased firing rate of the sensory afferents of the bladder wall results in increased parasympathetic outflow, decreased sympathetic outflow, and inhibiton of the somatic motor neurons resulting in bladder voiding.
Increased firing rate of the sensory afferents of the bladder wall results in decreased parasympathetic outflow, increased sympathetic outflow and inhibition of the somatic motor neurons resulting in bladder voiding.
Decreased firing rate of the sensory afferents of the bladder wall results in decreased parasympathetic outflow, decreased sympathetic outflow and excitation of the somatic motor neurons resulting in bladder voiding.
Increased firing rate of the sensory afferents of the bladder wall results in increased parasympathetic outflow, decreased sympathetic outflow, and inhibiton of the somatic motor neurons resulting in bladder voiding.
Explanation
When tension on the bladder wall reaches a threshold (full bladder), the sensory afferents increase their firing rate resulting in increased parasympathetic outflow and decreased sympathetic outflow resulting in the contraction of the detrusor muscle and relaxation of the internal sphincter. The sensory afferents also inhibit the somatic motor neurons that are mediating contraction of the external sphincter (results in relaxation of the skeletal muscle and opening of the sphincter).
In order to empty the bladder there needs to be contraction of the smooth muscle of the bladder wall (detrusor muscle), relaxation of the internal urethral sphincter, and contraction of the external urethral sphincter.
True or False
False
Explanation
This statement is false: While it is true that in order to empty the bladder contraction of the detrusor muscle and relaxation of the internal urethral sphincter are needed. The external sphincter must RELAX not CONTRACT.
Baroreceptors are located in the carotid sinus and the arotic arch and increased tension in the walls of these arteries causes a reduction in the firing rate of these receptors.
True or False
False
Explanation
This statement is false: While baroreceptors are located in the carotid sinus and aortic arch, increased tension in these vessels will INCREASE not DECREASE their firing rate.
Which of the following statements correctly describes what will happen during an acute episode of hypertension?
Baroreceptors will decrease their firing rate resulting in an increase in parasympathetic outflow and a decrease in sympathetic outflow producing the vasodepressor response.
Baroreceptors will increase their firing rate resulting in an increase in parasympathetic outflow and a decrease in sympathetic outflow producing the vasodepressor response.
Baroreceptors will decrease their firing rate resulting in an decrease in parasympathetic outflow and an increase in sympathetic outflow producing the vasopressor response.
Baroreceptors will increase their firing rate resulting in an decrease in parasympathetic outflow and a increase in sympathetic outflow producing the vasopressor response.
Baroreceptors will increase their firing rate resulting in an increase in parasympathetic outflow and a decrease in sympathetic outflow producing the vasodepressor response.
Explanation
During an episode of acute hypertension, baroreceptors will increase their firing rate resulting in an increase in parasympathetic outflow and a decrease in sympathetic outflow producing the vasodepressor response (lowering of heart rate and blood pressure). During an episode of acute hypotension, baroreceptors will decrease their firing rate resulting in an decrease in parasympathetic outflow and an increase in sympathetic outflow producing the vasopressor response (increase in heart rate and blood pressure).
Which part of the spinal cord do sympathetic preganglionic cells originate from?
a) Anterior horn
b) Posterior horn
c) Intermediolateral cell column (T1-L2)
d) Ventral root
Intermediolateral cell column (T1-L2)
Reason:
Preganglionic cells: originate in the intermediolateral cell column (T1-L2)
What neurotransmitter is released from sympathetic preganglionic neurons to post-ganglionic neurons?
a) Norepinephrine
b) Serotonin
c) Acetylcholine
d) Dopamine
Acetylcholine
Neurotransmitters: Acetylcholine (preganglionic → post-ganglionic)
Where are post-ganglionic neurons located in the sympathetic division?
a) In the spinal cord
b) In the brainstem
c) In the sympathetic chain of ganglia or prevertebral ganglia
d) In the parasympathetic ganglia
c) In the sympathetic chain of ganglia or prevertebral ganglia
What is the result of the interruption of the pathway through the superior cervical ganglion?
a) Hyperactivity of the sympathetic nervous system
b) Horner syndrome
c) Parasympathetic dominance
d) Increased sweating and pupil dilation
b) Horner syndrome
What are the characteristic symptoms of Horner syndrome?
a) Mydriasis, exophthalmos, hyperhidrosis, tachycardia
b) Miosis, ptosis, flushing of the face, anhidrosis
c) Photophobia, diplopia, nystagmus, lacrimation
d) Ataxia, dysarthria, dysphagia, intention tremor
b) Miosis, ptosis, flushing of the face, anhidrosis
Which neurotransmitter is used by both preganglionic and post-ganglionic neurons in the parasympathetic division?
a) Norepinephrine
b) Dopamine
c) Acetylcholine
d) Serotonin
Acetylcholine
Where are post-ganglionic neurons located in the parasympathetic division?
a) Spinal cord
b) Sympathetic chain ganglia
c) Ganglia in the head region and intramural ganglia
d) Thoracic cavity
Answer: c) Ganglia in the head region and intramural ganglia
Where do parasympathetic preganglionic neurons originate from?
a) Dorsal root ganglia
b) Sympathetic chain ganglia
c) Cranial visceromotor nuclei and S2-S4 spinal segments
d) Celiac ganglion
Answer: c) Cranial visceromotor nuclei and S2-S4 spinal segments
How do sympathetic viscerosensory neurons convey visceral pain?
a) They travel independently of somatic sensory neurons
b) They synapse directly with the cortex
c) They travel with somatic sensory neurons and send collaterals to synapse on posterior horn cells
d) They bypass the spinal cord and directly reach the brainstem
Answer: c) They travel with somatic sensory neurons and send collaterals to synapse on posterior horn cells
Why is visceral pain poorly localized?
a) Because it is primarily transmitted through the parasympathetic nervous system
b) Because the sympathetic viscerosensory neurons have large receptive fields and limited cortical representation
c) Because the spinal cord does not process visceral pain signals
d) Because visceral pain is primarily interpreted by the cerebellum
b) Because the sympathetic viscerosensory neurons have large receptive fields and limited cortical representation
How does the cortex interpret visceral pain signals?
a) As originating from the affected organ
b) As coming from the body surface (dermatomes)
c) As originating from the spinal cord
d) As originating from the brainstem
Answer: b) As coming from the body surface (dermatomes)
What prevents the bladder from emptying during the period of urine storage in the micturition reflex?
a) Increased parasympathetic outflow
b) Relaxation of the detrusor muscle
c) Contraction of the internal urethral sphincter (tonic activity in sympathetic neurons)
d) Contraction of the external urethral sphincter
Answer: c) Contraction of the internal urethral sphincter (tonic activity in sympathetic neurons)
Which part of the autonomic nervous system exhibits decreased activity during the period of urine storage in the micturition reflex?
a) Parasympathetic outflow
b) Sympathetic outflow
c) Enteric
d) Somatic
Answer: a) Parasympathetic outflow
What is the role of somatic motor neurons during the period of urine storage in the micturition reflex?
a) They relax the detrusor muscle
b) They contract the internal urethral sphincter
c) They contract the external urethral sphincter
d) They increase parasympathetic outflow
Answer: c) They contract the external urethral sphincter
What happens to parasympathetic outflow during micturition (emptying the full bladder) in the micturition reflex?
a) It decreases
b) It remains unchanged
c) It increases
d) It inhibits somatic motor neurons
It increases
- contraction of
detrusor muscle occur*
Which structure serves as the main coordinating center for micturition and is responsible for exerting voluntary control over the process?
a) Cerebellum
b) Medulla oblongata
c) Pons and frontal lobes
d) Hypothalamus
c) Pons and frontal lobes
What happens to INHIBITION of somatic motor neurons during micturition?
a) They contract the detrusor muscle
b) They contract the internal urethral sphincter
c) They relax the external urethral sphincter
d) They increase sympathetic outflow
Answer: c) They relax the external urethral sphincter
What is the primary role of baroreceptors response to hypertension in the context of blood pressure regulation?
a) To decrease their firing rate
b) To increase their firing rate
c) To maintain a constant firing rate
d) To activate sympathetic nervous system
b) To increase their firing rate
How does the solitary nucleus respond to hypertension?
a) It decreases its output
b) It increases its output
c) It remains unaffected
d) It inhibits parasympathetic activity
b) It increases its output
Which part of the nervous system experiences increased excitatory input during hypertension?
a) Dorsal motor vagal nucleus
b) Rostral anterolateral medulla
c) Sympathetic ganglia
d) Parasympathetic ganglia
Dorsal motor vagal nucleus
Reason:
Excitatory to dorsal motor vagal nucleus = increases
parasympathetic outflow
What effect does increased excitatory input to the dorsal motor vagal nucleus have on parasympathetic outflow?
a) It decreases parasympathetic outflow
b) It increases parasympathetic outflow
c) It has no effect on parasympathetic outflow
d) It inhibits the sympathetic nervous system
b) It increases parasympathetic outflow
What is the end result of the baroreceptor reflex in response to hypertension?
a) Vasopressor response
b) Decreased heart rate and blood pressure
c) Increased heart rate and blood pressure
d) Activation of the renin-angiotensin-aldosterone system
b) Decreased heart rate and blood pressure
Reason:
End result: vasodepressor response = decreased heart rate
and blood pressure
What is the primary response of baroreceptors to hypotension?
a) They maintain their firing rate
b) They decrease their firing rate
c) They increase their firing rate
d) They inhibit sympathetic activity
b) They decrease their firing rate
How does the solitary nucleus react to hypotension?
a) It increases its output
b) It decreases its output
c) It remains unchanged
d) It inhibits parasympathetic outflow
b) It decreases its output
What effect does the reduction in excitation of the dorsal motor vagal nucleus have during hypotension?
a) It increases parasympathetic outflow
b) It decreases parasympathetic outflow
c) It activates the sympathetic nervous system
d) It has no effect on autonomic outflow
b) It decreases parasympathetic outflow
What is the consequence of disinhibiting the rostral anterolateral medulla during hypotension?
a) Decreased heart rate and blood pressure
b) Increased heart rate and blood pressure
c) Activation of the parasympathetic nervous system
d) increase of sympathetic outflow
d) Increase of sympathetic outflow answer
Reason:
isinhibits rostral anterolateral medulla = increases
sympathetic outflow
What is the ultimate outcome of the baroreceptor reflex in response to hypotension?
a) Vasodepressor response
b) Increased heart rate and blood pressure
c) Decreased heart rate and blood pressure
d) Activation of the renin-angiotensin-aldosterone system
b) Increased heart rate and blood pressure
Reason:
End result: vasopressor response = increased heart rate and
blood pressure
What is the key to restoring imbalance during uncontrolled hypertension episode of autonomic dysreflexia?
a) Administering sympathetic blockers
b) Administering parasympathetic stimulants
c) Removing the noxious stimulus
d) Initiating immediate surgery
c) Removing the noxious stimulus
What is the consequence of the parasympathetic response during autonomic dysreflexia?
a) Bradycardia
b) Tachycardia
c) Hypotension
d) Vasodilation
a) Bradycardia
Reason:
Parasympathetic response causes a reduction in heart rate (bradycardia), but the
inhibitory impulse is unable to reach targets below the level of the SCI, resulting
in a parasympathetic response above the injury and a sympathetic response
below the injury
How do baroreceptors respond to the rise in blood pressure during autonomic dysreflexia?
a) They decrease their firing rate
b) They increase their firing rate
c) They remain unchanged
d) They become dysfunctional
b) They increase their firing rate
Reason:
Baroreceptors detect rise in blood pressure (increase firing to the solitary
nucleus which sends inhibitory input to the anterolateral medulla and excitatory
input to the dorsal motor vagal nucleus).
What type of stimulus below the level of injury is most likely to trigger autonomic dysreflexia?
a) Visual stimulus
b) Auditory stimulus
c) Noxious stimulus
d) Thermal stimulus
c) Noxious stimulus
Reason:
A noxious stimulus below the level of injury (usually bowel or bladder related)
will initiate a peripheral sympathetic response through spinal reflexes, resulting
in peripheral arterial hypertension
At what level of spinal cord injury (SCI) can autonomic dysreflexia typically develop?
a) T2 level
b) T6 level
c) L1 level
d) S1 level
b) T6 level
Reason:
Can develop in individuals with SCI at or above the T6 level resulting in acute, uncontrolled hypertension.
Which of the following is NOT a potential consequence of autonomic dysreflexia?
a) Seizures
b) Retinal hemorrhage
c) Hypotension
d) Myocardial infarction
c) Hypotension
Reason:
Life-threatening medical emergency; can cause seizures, retinal hemorrhage,
pulmonary edema, renal insufficiency, myocardial infarction, cerebral
hemorrhage, and death.
What is the primary cause of autonomic dysreflexia?
a) Parasympathetic overactivation
b) Sympathetic overactivation
c) Baroreceptor dysfunction
d) Imbalance between parasympathetic and sympathetic control of blood pressure
d) Imbalance between parasympathetic and sympathetic control of blood pressure
Which structure is responsible for secreting melatonin?
a) Hypothalamus
b) Pineal gland
c) Pituitary gland
d) Thyroid gland
b) Pineal gland
What activates the neurons of the superchiasmatic nucleus during daylight?
a) Melatonin secretion
b) Inhibition by the pineal gland
c) Activation by light
d) Stimulation by the PV nucleus
c) Activation by light
What effect does activation of the superchiasmatic nucleus have on the neurons of the PV nucleus?
a) Activation
b) Inhibition
c) Stimulation
d) No effect
Answer: b) Inhibition
What is the typical role of the PV nucleus in melatonin secretion?
a) Inhibition of melatonin secretion
b) Stimulation of melatonin secretion
c) Regulation of cortisol secretion
d) Control of insulin release
Answer: a) Inhibition of melatonin secretion
What happens to sympathetic outflow during the onset of darkness?
a) It decreases
b) It increases
c) It remains constant
d) It becomes irregular
Answer: b) It increases
