245.A 26-year-old woman is in her last trimester of a normal pregnancy.
Synthesis of milk by her mammary glands specifically requires which of the
following?
a. Oxytocin from the neurohypophysis
b. Prolactin from the corpus luteum
c. The influence of vasopressin
d. Placental lactogen
e. Neurohumoral reflexes
246.The urologist may describe the reattachment of a severed vas defer-
ens (vasovasostomy) as successful, more than 90% of the time. However, it
is unsuccessful from the patients’ point of view since a much lower per-
centage of these men can father a child. The difference in success rate is due
to which of the following?
a. Spermatogonia are exposed to humoral factors
b. Genetic recombination in haploid sperm creates novel antigens
c. Cryptorchid testes are often incapable of producing fertile sperm
d. Vasectomy prevents phagocytosis of sperm by macrophages
e. Sperm coated with autoimmune antibodies are unable to fertilize an egg
Reproductive Systems 367