Where are the cell bodies of sympathetic preganglionic neurons located?
Lateral horns of the thoracic and upper lumbar spinal cord
✓
Brain stem nuclei and the sacral spinal cord
Dorsal root ganglia of the cervical spinal nerves
Anterior horns of the lumbar and sacral spinal cord
Correct Answer
Lateral horns of the thoracic and upper lumbar spinal cord
Sympathetic preganglionic neurons sit in the lateral gray horns from about T1 to L2, which is why the division is called thoracolumbar. Brain stem nuclei and the sacral spinal cord are the origins of the parasympathetic division. Dorsal root ganglia of the cervical spinal nerves hold sensory neuron cell bodies, not autonomic motor neurons. Anterior horns of the lumbar and sacral spinal cord contain somatic motor neurons to skeletal muscle.
Category: Sympathetic Division
Question 2
Which neurotransmitter is released by all autonomic preganglionic fibers?
Norepinephrine
Acetylcholine
✓
Epinephrine
Dopamine
Correct Answer
Acetylcholine
Every autonomic preganglionic neuron, sympathetic or parasympathetic, is cholinergic and releases acetylcholine onto the postganglionic neuron. Norepinephrine is released by most sympathetic postganglionic fibers, not preganglionic ones. Epinephrine is mainly a hormone secreted by the adrenal medulla. Dopamine is not the transmitter at autonomic ganglia.
Category: Chemical Signaling
Question 3
Which receptor, a ligand-gated cation channel, is found on postganglionic neurons in autonomic ganglia?
Muscarinic receptor
Alpha-1 adrenergic receptor
Nicotinic receptor
✓
Beta-2 adrenergic receptor
Correct Answer
Nicotinic receptor
Nicotinic receptors are ion channels that open when acetylcholine binds, depolarizing the postganglionic neuron in both divisions. Muscarinic receptor is a G protein-coupled acetylcholine receptor on target organs, not a channel. Alpha-1 adrenergic receptor binds norepinephrine on target tissues such as vascular smooth muscle. Beta-2 adrenergic receptor binds catecholamines on targets such as bronchiolar smooth muscle.
Category: Chemical Signaling
Question 4
Which cranial nerve carries parasympathetic fibers to the heart, lungs and most abdominal organs?
Oculomotor nerve
Facial nerve
Glossopharyngeal nerve
Vagus nerve
✓
Correct Answer
Vagus nerve
The vagus nerve (cranial nerve X) supplies parasympathetic output to the thoracic organs and most of the digestive tract. Oculomotor nerve carries parasympathetic fibers to the iris and ciliary muscle. Facial nerve supplies the lacrimal glands and some salivary glands. Glossopharyngeal nerve supplies the parotid salivary gland.
Category: Parasympathetic Division
Question 5
At which target are sympathetic postganglionic fibers cholinergic rather than releasing norepinephrine?
Sweat glands
✓
Heart
Iris dilator muscle
Salivary glands
Correct Answer
Sweat glands
Most sweat glands are innervated by sympathetic postganglionic fibers that are cholinergic and act on muscarinic receptors. Heart receives norepinephrine from sympathetic fibers, which acts on beta-1 receptors. Iris dilator muscle contracts in response to norepinephrine. Salivary glands receive norepinephrine from their sympathetic supply.
Category: Chemical Signaling
Question 6
Chromaffin cells that secrete epinephrine into the blood are contacted directly by preganglionic sympathetic fibers in which organ?
Adrenal cortex
Adrenal medulla
✓
Pancreas
Kidney
Correct Answer
Adrenal medulla
The adrenal medulla acts like a modified sympathetic ganglion: preganglionic fibers synapse directly on its chromaffin cells, which release epinephrine and norepinephrine as hormones. Adrenal cortex is endocrine tissue that secretes steroid hormones and is not innervated this way. Pancreas has endocrine islets but no chromaffin cells. Kidney is a sympathetic target but does not secrete epinephrine.
Category: Sympathetic Division
Question 7
Which of these is a collateral (prevertebral) ganglion of the sympathetic division?
Ciliary ganglion
Superior cervical ganglion
Celiac ganglion
✓
Otic ganglion
Correct Answer
Celiac ganglion
Collateral ganglia lie anterior to the vertebral column near major abdominal arteries; the celiac ganglion serves organs such as the stomach. Ciliary ganglion is a parasympathetic ganglion in the orbit. Superior cervical ganglion is part of the sympathetic chain beside the vertebral column. Otic ganglion is a parasympathetic ganglion serving the parotid gland.
Category: Sympathetic Division
Question 8
Myelinated preganglionic sympathetic axons pass from a spinal nerve into the sympathetic chain through which structure?
Gray ramus communicans
Dorsal root
Splanchnic nerve
White ramus communicans
✓
Correct Answer
White ramus communicans
The white ramus communicans carries myelinated preganglionic fibers from the spinal nerve to the chain ganglion, and the myelin gives it its white color. Gray ramus communicans carries unmyelinated postganglionic fibers back to the spinal nerve. Dorsal root carries sensory fibers into the cord, while autonomic motor fibers leave through the ventral root. Splanchnic nerve carries preganglionic fibers out of the chain toward collateral ganglia.
Category: Sympathetic Division
Question 9
Where are most parasympathetic ganglia located?
In or near the target organ
✓
Alongside the vertebral column
Anterior to the abdominal aorta
Within the dorsal root
Correct Answer
In or near the target organ
Parasympathetic ganglia are terminal ganglia in or near the organ they serve, so preganglionic fibers are long and postganglionic fibers are short. Alongside the vertebral column is where sympathetic chain ganglia lie. Anterior to the abdominal aorta is where sympathetic collateral ganglia lie. Within the dorsal root is the location of sensory ganglia, not autonomic ones.
Category: Parasympathetic Division
Question 10
In bright light, parasympathetic fibers that constrict the pupil synapse in which ganglion?
Superior cervical ganglion
Ciliary ganglion
✓
Celiac ganglion
Pterygopalatine ganglion
Correct Answer
Ciliary ganglion
Preganglionic fibers travel in the oculomotor nerve to the ciliary ganglion, whose postganglionic fibers release acetylcholine onto the circular muscle of the iris. Superior cervical ganglion relays the sympathetic pathway that dilates the pupil. Celiac ganglion is a sympathetic collateral ganglion for abdominal organs. Pterygopalatine ganglion relays parasympathetic fibers to the lacrimal gland.
Category: Parasympathetic Division
Question 11
Which type of autonomic reflex uses enteric neurons in the gut wall without involving the central nervous system?
Long reflex
Somatic reflex
Short reflex
✓
Stretch reflex
Correct Answer
Short reflex
A short reflex is entirely peripheral: a sensory signal such as stomach stretch acts on local enteric neurons that change motility or secretion. Long reflex sends sensory input to the spinal cord or brain before an autonomic response. Somatic reflex controls skeletal muscle, not visceral effectors. Stretch reflex is a spinal somatic reflex such as the knee jerk.
Category: Reflexes and Homeostasis
Question 12
Metoprolol, used to slow the heart in cardiovascular disease, selectively blocks which receptor?
Alpha-1 receptor
Muscarinic receptor
Nicotinic receptor
Beta-1 receptor
✓
Correct Answer
Beta-1 receptor
Metoprolol is a selective beta blocker that acts on beta-1 receptors, which dominate in the heart, reducing heart rate and force of contraction. Alpha-1 receptor is blocked by alpha blockers and mainly controls vascular smooth muscle. Muscarinic receptor is blocked by drugs such as atropine. Nicotinic receptor is found at autonomic ganglia and the neuromuscular junction.
Category: Autonomic Drugs
Question 13
A sudden rise in arterial blood pressure triggers which response through the baroreceptor reflex?
Decrease in heart rate
✓
Increase in heart rate
Constriction of arterioles
Increase in stroke volume
Correct Answer
Decrease in heart rate
Stretch of the carotid and aortic baroreceptors increases parasympathetic output and decreases sympathetic output, slowing the heart and lowering pressure back toward normal. Increase in heart rate would raise pressure further. Constriction of arterioles would also raise pressure; the reflex instead allows vessels to dilate. Increase in stroke volume would raise cardiac output and pressure.
Category: Reflexes and Homeostasis
Question 14
Which cranial nerve carries sensory signals from carotid sinus baroreceptors to the brain stem?
Vagus nerve
Glossopharyngeal nerve
✓
Hypoglossal nerve
Accessory nerve
Correct Answer
Glossopharyngeal nerve
Carotid sinus baroreceptor axons travel in the glossopharyngeal nerve (cranial nerve IX) to the medulla. Vagus nerve carries signals from the aortic arch baroreceptors. Hypoglossal nerve is a motor nerve to the tongue muscles. Accessory nerve is a motor nerve to the sternocleidomastoid and trapezius.
Category: Reflexes and Homeostasis
Question 15
A drug that mimics or enhances the effects of norepinephrine at adrenergic receptors is classified as which type?
Sympatholytic
Parasympathomimetic
Sympathomimetic
✓
Anticholinergic
Correct Answer
Sympathomimetic
Sympathomimetic drugs imitate or boost sympathetic signaling, for example by activating adrenergic receptors or increasing norepinephrine release. Sympatholytic drugs block adrenergic function, as beta blockers do. Parasympathomimetic drugs enhance cholinergic effects at muscarinic receptors. Anticholinergic drugs block acetylcholine receptors.
Category: Autonomic Drugs
Question 16
Atropine dilates the pupil because it acts as which kind of drug?
Nicotinic agonist
Beta-adrenergic antagonist
Alpha-1 adrenergic agonist
Muscarinic antagonist
✓
Correct Answer
Muscarinic antagonist
Atropine blocks muscarinic receptors on the circular muscle of the iris, so parasympathetic constriction is lost and the pupil dilates. Nicotinic agonist describes nicotine, which acts at autonomic ganglia. Beta-adrenergic antagonist describes beta blockers such as propranolol. Alpha-1 adrenergic agonist describes phenylephrine, which dilates the pupil by a different mechanism.
Category: Autonomic Drugs
Question 17
Which brain stem region contains the cardiovascular center that adjusts heart rate and blood vessel diameter?
Medulla oblongata
✓
Midbrain
Pons
Thalamus
Correct Answer
Medulla oblongata
The cardiovascular center in the medulla oblongata directs sympathetic and parasympathetic output to the heart and blood vessels. Midbrain contains visual and auditory reflex centers and the oculomotor nuclei. Pons relays signals and helps regulate breathing. Thalamus is a sensory relay in the diencephalon, not part of the brain stem.
Category: Central Control
Question 18
Which limbic structure in the medial temporal lobe signals the hypothalamus to start the fight-or-flight response during fear?
Hippocampus
Amygdala
✓
Cingulate gyrus
Fornix
Correct Answer
Amygdala
The amygdala processes fear and emotional memory and drives the hypothalamus to activate sympathetic output and stress hormone release. Hippocampus is mainly involved in forming new memories. Cingulate gyrus is a limbic cortex region involved in emotion and attention, but it is not the fear center. Fornix is a fiber tract connecting the hippocampus to the hypothalamus.
Category: Central Control
Question 19
Preganglionic parasympathetic neurons that control the pupil are located in which brain stem nucleus?
Solitary nucleus
Nucleus ambiguus
Edinger-Westphal nucleus
✓
Vestibular nucleus
Correct Answer
Edinger-Westphal nucleus
The Edinger-Westphal nucleus in the midbrain sends parasympathetic fibers through the oculomotor nerve to the ciliary ganglion. Solitary nucleus receives visceral sensory input such as blood pressure signals. Nucleus ambiguus supplies vagal motor output to the pharynx and larynx. Vestibular nucleus processes balance information from the inner ear.
Category: Central Control
Question 20
Which medullary nucleus receives visceral sensory input about blood pressure and heart activity?
Dorsal motor nucleus of the vagus
Edinger-Westphal nucleus
Nucleus ambiguus
Solitary nucleus
✓
Correct Answer
Solitary nucleus
The solitary nucleus is the main visceral sensory nucleus of the brain stem and receives baroreceptor input carried by cranial nerves IX and X. Dorsal motor nucleus of the vagus is a parasympathetic motor nucleus that slows the heart. Edinger-Westphal nucleus is a parasympathetic nucleus for the pupil. Nucleus ambiguus provides motor output for swallowing and speech.
Category: Central Control