Chapter 21

Instructions

Choose your answers from a-d by clicking the radio button next to each choice and then press 'Submit' to get your score.

Regarding the sexual reflexes and fertilization:

a) Erection is a sympathetic reflex.

b) During ejaculation the sperm are mixed with secretions from the prostate and seminal vesicles.

c) Fertilization normally occurs in the uterus.

d) Fertilization may occur three or more days after ovulation.

Regarding the sperm and ova:

a) A normal sperm count is about 20 million.

b) Immediately after ejaculation, the sperm are capable of fertilizing an ovum.

c) The fertilized egg secretes hPL to maintain the corpus luteum.

d) Following fertilization the egg completes its second meiotic division.

Regarding the functions of the placenta:

a) The placenta nourishes the fetus by establishing a dialysis pattern for exchange between the maternal and fetal circulations.

b) The placental barrier is very thin and freely permeable to glucose and amino acids.

c) The PO₂ of the blood of the umbilical vein is the same as that in the maternal arterial blood.

d) The estrogens secreted by the placenta tend to inhibit uterine excitability during pregnancy.

During pregnancy:

a) Plasma hCG levels peak between weeks 10 and 14 of gestation.

b) Placental progesterone secretion is highest in the first 8 weeks of gestation.

c) Blood flow to the kidneys is unchanged.

d) Maternal respiratory rate is increased.

Regarding the control of lactation:

a) Prolactin stimulates milk ejection.

b) Placental steroid secretion inhibits lactation during pregnancy.

c) Vasopressin (ADH) is secreted in response to suckling.

d) Oxytocin secretion can be suppressed by dopamine agonists.