In the sympathetic division, preganglionic fibers are usually short and postganglionic fibers are usually long.
Correct Answer
True
True. Most sympathetic ganglia lie in the chain beside the spinal cord, so the preganglionic fiber has only a short distance to travel and the postganglionic fiber runs the long distance to the target.
Category: Sympathetic Division
Question 2
Parasympathetic stimulation decreases digestive motility and secretion.
Correct Answer
False
False. Parasympathetic stimulation increases digestive motility and secretion as part of rest-and-digest activity. Sympathetic stimulation is what slows digestion.
Category: Parasympathetic Division
Question 3
Muscarinic and adrenergic receptors are both G protein-coupled receptors.
Correct Answer
True
True. Muscarinic receptors (for acetylcholine) and adrenergic alpha and beta receptors (for norepinephrine and epinephrine) all act through G proteins, unlike nicotinic receptors, which are ion channels.
Category: Chemical Signaling
Question 4
Most sympathetic postganglionic fibers release acetylcholine onto their target organs.
Correct Answer
False
False. Most sympathetic postganglionic fibers are adrenergic and release norepinephrine. Acetylcholine is released by all preganglionic fibers, by parasympathetic postganglionic fibers and by the sympathetic fibers to most sweat glands.
Category: Chemical Signaling
Question 5
A single sympathetic preganglionic fiber can synapse with many postganglionic neurons, which helps produce widespread effects.
Correct Answer
True
True. Sympathetic preganglionic fibers branch extensively and synapse in several ganglia, so one signal spreads to many postganglionic neurons. This divergence supports a body-wide fight-or-flight response.
Category: Sympathetic Division
Question 6
Parasympathetic fibers in the oculomotor nerve stimulate the lacrimal glands to produce tears.
Correct Answer
False
False. The parasympathetic fibers that stimulate tear production travel in the facial nerve. The oculomotor nerve carries parasympathetic fibers to the iris and ciliary muscle of the eye.
Category: Parasympathetic Division
Question 7
Parasympathetic stimulation dilates the bronchioles.
Correct Answer
False
False. Parasympathetic stimulation through the vagus nerve constricts the bronchioles. Sympathetic activity dilates them, increasing airflow during exertion.
Category: Parasympathetic Division
Question 8
Systemic blood vessels are under sympathetic tone because they receive little or no parasympathetic input.
Correct Answer
True
True. Most blood vessels are supplied only by sympathetic fibers, so their diameter is set by raising or lowering the level of sympathetic activity rather than by a balance between divisions.
Category: Reflexes and Homeostasis
Question 9
Without any autonomic input, the heart's pacemaker would set a resting rate of about 40 beats per minute.
Correct Answer
False
False. The intrinsic rate of the sinoatrial node is about 100 beats per minute. Parasympathetic tone through the vagus nerve slows the resting heart rate below that value.
Category: Reflexes and Homeostasis
Question 10
Visceral pain can be felt in a skin region whose sensory fibers enter the spinal cord at the same level as the organ's fibers.
Correct Answer
True
True. This is referred pain. Because visceral and somatic sensory fibers converge on the same spinal segments, the brain misreads pain from an organ such as the heart as coming from the body surface, such as the left arm.
Category: Reflexes and Homeostasis
Question 11
During sympathetic activation, blood vessels in skeletal muscle constrict to send more blood to the digestive organs.
Correct Answer
False
False. During sympathetic activation, blood vessels in active skeletal muscle dilate to supply the muscles, while blood flow to the digestive organs is reduced.
Category: Reflexes and Homeostasis
Question 12
When a person stands up quickly, increased sympathetic output raises heart rate and constricts blood vessels to maintain blood flow to the brain.
Correct Answer
True
True. This orthostatic reflex counters the drop in blood pressure caused by blood pooling in the legs, keeping enough blood flowing to the brain.
Category: Reflexes and Homeostasis
Question 13
Exercise raises heart rate by increasing sympathetic input and decreasing parasympathetic input to the heart.
Correct Answer
True
True. During exercise, brain centers shift autonomic output toward the sympathetic division, which speeds the heart, and reduce the vagal input that normally slows it at rest.
Category: Central Control
Question 14
The dorsal motor nucleus of the vagus provides sympathetic output that increases heart rate.
Correct Answer
False
False. The dorsal motor nucleus of the vagus is a parasympathetic motor nucleus in the medulla, and its output slows the heart, constricts the bronchi and stimulates digestion.
Category: Central Control
Question 15
The optic nerve provides the sensory limb of the pupillary light reflex.
Correct Answer
True
True. Light detected by the retina is carried by the optic nerve to the brain, which then adjusts pupil size through parasympathetic or sympathetic motor pathways.
Category: Central Control
Question 16
Because nicotine stimulates both autonomic divisions at the ganglia, it has no net effect on the cardiovascular system.
Correct Answer
False
False. Although many opposing effects cancel out, nicotine shifts blood vessels toward sympathetic constriction and raises blood pressure, and it can cause arrhythmias. This is one reason smoking is a cardiovascular risk factor.
Category: Autonomic Drugs
Question 17
Blocking muscarinic receptors throughout the body reduces salivation and increases heart rate.
Correct Answer
True
True. Muscarinic antagonists remove parasympathetic effects, so salivary secretion drops, causing dry mouth, and the heart speeds up because vagal slowing is lost.
Category: Autonomic Drugs
Question 18
Propranolol is a beta blocker that selectively blocks only beta-1 receptors.
Correct Answer
False
False. Propranolol is a nonselective beta blocker that blocks both beta-1 and beta-2 receptors. Drugs such as metoprolol are the beta-1 selective blockers.
Category: Autonomic Drugs
Question 19
Caffeine increases sympathetic activity by directly stimulating beta-adrenergic receptors.
Correct Answer
False
False. Caffeine blocks adenosine receptors. Because adenosine normally suppresses norepinephrine release, blocking it indirectly increases sympathetic activity.
Category: Autonomic Drugs
Question 20
Phenylephrine is an alpha-1 adrenergic agonist that is used to dilate the pupil for eye exams.
Correct Answer
True
True. Phenylephrine activates alpha-1 receptors on the radial dilator muscle of the iris, widening the pupil so the interior of the eye can be examined.
Category: Autonomic Drugs