Chapter 10 Flashcards
Pancreatic islets consist of alpha, beta, and
delta cells, which secrete glucagon, insulin,
and somatostatin, respectively. These cells are
derived from
(A) mesoderm
(B) endoderm
(C) ectoderm
(D) neuroectoderm
(E) neural crest cells
B. Pancreatic islets form as isolated clumps of cells that bud from endodermal tubules.
A 2-month-old baby with severe jaundice also has dark-colored urine (deep yellow) and white clay-colored stool. Which of the following disorders might be suspected? (A) Esophageal stenosis (B) Annular pancreas (C) Hypertrophic pyloric stenosis (D) Extrahepatic biliary atresia (E) Duodenal atresia
D. The baby is suffering from extrahepatic biliary atresia, which results from failure of the bile
ducts to recanalize during development. This prevents bile from entering the duodenum.
A 28-day-old baby is brought to the physician
because of projectile vomiting after feeding.
Until this time, the baby has had no problems
in feeding. On examination, a small knot
is palpated at the right costal margin. Which of
the following disorders might be suspected?
(A) Esophageal stenosis
(B) Annular pancreas
(C) Hypertrophic pyloric stenosis
(D) Extrahepatic biliary atresia
(E) Duodenal atresia
C. The baby is suffering from hypertrophic pyloric stenosis. This occurs when the smooth
muscle in the pyloric region of the stomach hypertrophies and obstructs passage of food. The
hypertrophied muscle can be palpated at the right costal margin. The exact cause of this condition
is not known.
The most common type of anorectal malformation is (A) imperforate anus (B) anal agenesis (C) anorectal agenesis (D) rectal atresia (E) colonic aganglionosis
C. The most common type of malformation involving the anal canal and rectum is anorectal
agenesis, in which the rectum ends as a blind sac above the puborectalis muscle. The anal canal
may form normally but does not connect with the rectum. This malformation is accompanied by
various fistulas.
The simple columnar or cuboidal epithelium lining the extrahepatic biliary ducts is derived from (A) mesoderm (B) endoderm (C) ectoderm (D) neuroectoderm (E) neural crest cells
B. The epithelium lining the extrahepatic biliary ducts is derived from endoderm. The intrahepatic
biliary ducts are also derived from endoderm.
Which one of the following structures is derived from the midgut? (A) Appendix (B) Stomach (C) Liver (D) Pancreas (E) Sigmoid colon
A. The appendix is derived from the midgut. The midgut normally undergoes a 270° counterclockwise rotation during development; malrotation of the midgut may result in the appendix lying in the upper part of the abdominal cavity, which may affect a diagnosis of appendicitis.
Kupffer cells present in the adult liver are derived from (A) mesoderm (B) endoderm (C) ectoderm (D) neuroectoderm (E) neural crest cells
A. Kupffer cells are actually macrophages and are derived from mesoderm. Hepatocytes and the epithelial lining of the intrahepatic biliary tree are derived from endoderm.
A baby born to a young woman whose
pregnancy was complicated by polyhydramnios
was placed in the intensive care unit
because of repeated vomiting containing bile.
The stomach was markedly distended, and
only small amounts of meconium had passed
through the anus. What is the most likely diagnosis?
(A) Esophageal stenosis
(B) Annular pancreas
(C) Hypertrophic pyloric stenosis
(D) Extrahepatic biliary atresia
(E) Duodenal atresia
E. This baby is suffering from duodenal atresia at a level distal to the opening of the common bile duct. This causes a reflux of bile and its presence in the vomitus. The pregnancy was complicated by polyhydramnios because the duodenal atresia prevented passage of amniotic fluid into the intestines for absorption.
