sperm motility. The flavins that are contributed to the ejaculate by the sem-
inal vesicles fluoresce strongly in ultraviolet light, a phenomenon that sup-
plies a useful forensic test for the presence of semen. Bulbourethral glands
(answer a)produce mucus that lubricates the urethra upon erotic stimulus.
The epididymis (answer b) stores sperm. The prostate gland (answer c)
produces proteins responsible for semen liquefaction. The testis (answer e)
produces sperm.
425.The answer is b.(Moore and Dalley, pp 396–371, 436–438.)The
muscle indicated is attached to the pubic bone and extends around the rec-
tum. It is the puborectalis portion of the levator ani (pelvic diaphragm).
The puborectalis is responsible for fecal continence. The urogenital
diaphragm(answer a)is positioned inferior to the pelvic diaphragm and
includes the deep transverse perineal muscle. The obturator internus
(answer c)covers the lateral wall of the lesser pelvis. The obturator exter-
nus(answer d)is found in the deep thigh.
426.The answer is c.(Moore and Dalley, p 409. Kierszenbaum, p 559.)
Benign prostatic hypertrophy is the result of enlargement of the mucosal
and submucosal (median) region, which may compress the prostatic ure-
thra leading to urinary retention [thus not (answer a)]. This hypertrophic
tissue may also protrude into the urinary bladder to prevent complete
emptying. The lateral/posterior lobes (answer b)are commonly associated
with malignant transformation. The anterior region (answer d)tends to be
asymptomatic due to its mainly fibrous nature.
427.The answer is c.(Moore and Dalley, p 431.)Lymph from the anal
region is drained to three different regions because its blood supply comes
from three different regions [thus (answers a and b)are incomplete].
Superior to the pectinate line the lymph drains into the internal iliac nodes
and preaortic nodes (along the path of the superior rectal artery, a branch
off the inferior mesenteric artery). Inferior to the pectinate line the lymph
drains into the superficial inguinal nodes. Thus the external iliac nodes
have nothing to do with the rectum [thus not (answers d and e)].
428.The answer is e.(Moore and Dalley, pp 384–386.)All of the listed
choices are branches of the internal iliac artery. The inferior vesical artery
550 Anatomy, Histology, and Cell Biology