(answer e)is due to mild, chronic unconjugated hyperbilirubinemia and
isnotinvolved.
377.The answer is a.(Moore and Dalley, p 256.)Blockage of the foregut
in the newborn produces projectile vomiting. Congenital hypertrophic
pyloric stenosis, occurring in 0.5–1.0% of males and rarely in females,
involves hypertrophy of the circular layer of muscle at the pylorus. This
usually does notregress and must be treated surgically. During the 5th and
6th weeks of development, the lumen of the duodenum is occluded by
muscle proliferation but normally recanalizes during the eighth week. Fail-
ure of recanalization results in duodenal atresia. Because this occurs proxi-
mal to the hepatopancreatic ampulla, the vomitus will occasionally be
stained with bile. Annular pancreas, rare in itself, seldom completely
blocks the duodenum. Congenital absence of a kidney (answer b)would
notpresent with the symptoms described. Imperforate anus (answer d)
results in intestinal distention with bloating. A newborn with a typical tra-
cheoesophageal fistula (answer e)cannotfeed without aspiration. A new-
born with a patent ileal diverticulum (answer c)would present with stool
coming out his umbilicus.
378.The answer is c.(Moore and Dalley, p 276.)Preganglionic parasym-
pathetic neurons to the lower colon arise from the spinal cord at sacral lev-
els two to four (thus not answer b) and reach the wall of the colon via
pelvic splanchnic nerves. The nucleus ambiguus is the source of pregan-
glionic parasympathetic neurons that innervate the heart via the vagus
nerve and cardiac plexus (answer a and d).Neurons arising in the cervi-
cal intermediolateral cell column are sympathetic preganglionics. Pregan-
glionic parasympathetic neurons arising from the motor nucleus of the
vagus innervate the upper GI tract. Neurons arising from the ventral horn
are primary somatic motor neurons to skeletal muscle (answer e).
379.The answer is b.(Moore and Dalley, pp 284–285, 288.)The surgeon
will inject 50% ethanol to kill nerve cells around the celiac trunk. Palliative
pain relief for pancreatic cancer is called chemical splanchnicectomy. The
purpose is to kill afferent pain fibers which detect free ATP (from dying
cells) and stretch receptors for the foregut area, affected by the cancer. This
is best accomplished by injecting ethanol around the celiac trunk at the pos-
terior abdominal wall, thus at the celiac plexus. Injection of each subcostal
Abdomen Answers 517