Physical examination of a young boy reveals discharge of urine from the umbilicus. The physician concludes that the urachus has failed to fuse. Which of the following structures is the normal adult remnant of the fused urachus?
A. Lateral umbilical fold
B. Medial umbilical fold
C. Medial umbilical ligament
D. Median umbilical fold
E. Median umbilical ligament
Answer
A newborn boy does not pass meconium until 48 hours after his birth. Two weeks later his mother reports that he has not been passing stool regularly. Anorectal manometry reveals increased internal anal sphincter pressure on rectal distention with a balloon. Radiographic studies reveal massive dilation of the colon proximal to the rectum. This indicates a developmental abnormality in which of the following embryonic tissues?
A. Ectoderm
B. Endoderm
C. Neural crest
D. Neural ectoderm
E. Splanchnic mesoderm
Answer
Which of the following embryonic structures gives rise to the adrenal cortex?
A. Ectoderm
B. Endoderm
C. Mesoderm
D. Mesonephros
E. Neural crest cells
Answer
Which of the following cell types is derived from neuroepithelial cells?
A. Astrocytes
B. Enterochromaffin cells
C. Melanocytes
D. Odontoblasts
E. Schwann cells
Answer
When examining a histological section of a normal ovary, a technician notices an oocyte surrounded by several layers of follicular cells. A small antrum is present. Which of the following is the correct term for the entire structure, composed of the oocyte, follicular cells, and antrum?
A. Corpus luteum
B. Graafian follicle
C. Primary follicle
D. Primordial follicle
E. Secondary follicle
Answer
