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metabolites (carbon dioxide and oxygen) than to innervation by the autonomic nervous system
11-B. Sympathetic stimulation results in dilation of the pupils (mydriasis), dilation of the lumina
of the bronchi, increased perspiration (sudation), and constriction of the ductus deferens (resulting
in ejaculation). Contraction of the detrusor muscle is a parasympathetic function.
12-C. The vagal nerve (CN X) contains preganglionic fibers from the nucleus ambiguus that ter-
minate in the cardiac ganglia. It innervates the esophagus, thoracic viscera, and abdominal vis-
cera, excluding the descending colon, sigmoid colon, and rectum, which are innervated by the
pelvic nerve (S2-S4). The carotid sinus (baroreceptor) is innervated by the glossopharyngeal nerve
(CN IX; sinus nerve). The carotid body (chemoreceptor) is innervated by the glossopharyngeal and
13-D. Preganglionic parasympathetic fibers arise from the Edinger-Westphal nucleus of CN III,
superior salivatory nucleus of CN VII, inferior salivatory nucleus of CN EX, and dorsal motor
nucleus and nucleus ambiguus of CN X. Preganglionic parasympathetic fibers from sacral seg-
ments (S2-S4) traverse the pelvic nerves; they do not traverse the white communicating rami.
The otic ganglion receives preganglionic parasympathetic input from the inferior salivatory
nucleus of CNDL
14-E. Horner's syndrome is caused by all lesions that interrupt sympathetic input to the eye. A
lesion of the ciliary ganglion results in denervation of the sphincter pupillae muscle of the iris and
the ciliary muscle. Postganglionic sympathetic fibers that innervate the dilator pupillae muscle
and the smooth tarsal muscle do not traverse the ciliary ganglion.
15-C. Peptic ulcer disease results from increased parasympathetic tone.
16-E. Raynaud's disease is a benign symmetric disease characterized by painful vasospasms
affecting the digits.
17-D. Riley-Day syndrome, familial dysautonomia, is an autosomal recessive trait characterized
by abnormal sweating and blood pressure instability.
Chapter 18 Autonomic Nervous System I 287
18-A. Congenital aganglionic megacolon, or Hirschsprung's disease, results from failure of the
neural crest cells to migrate into the wall of the distal colon (sigmoid colon and rectum) and form
the myenteric plexus. It is characterized by extreme dilation and hypertrophy of the colon, with
19-B. Anisocoria (unequal pupils) and hemianhidrosis (lack of sweating on half of the face) are
consistent with Homer's syndrome (ptosis, miosis, and hemianhidrosis).
20-E. Vasoactive intestinal polypeptide (VIP) is a vasodilator found in postganglionic parasympa-
thetic fibers, co-localized with acetylcholine (ACh).
21-B. Dopamine is the neurotransmitter of the small intensely fluorescent (SIF) cells.
22-D. Norepinephrine innervates apocrine sweat glands; these glands of the axilla and anal
region respond to emotional stress.
23-A. Acetylcholine (ACh) innervates eccrine (merocrine) sweat glands, which respond to heat
24-C. Nitric oxide is the transmitter responsible for penile erection. 25-D.
Norepinephrine is the neurotransmitter of the arrector pili muscles.
I. Overview—The Hypothalamus
-is a division of the diencephalo n.
-lies within the floor and ventral part of the walls of the third ventricle, —
functions primarily in the maintenance of homeostasis. -subserves three