Ch.17 Reproduction

Semelparity versus iteroparity?

One major lifetime reproductive episode versus repeated episodes.

How does photoperiod influence reproduction?

Retina–SCN–pineal signaling alters melatonin duration and seasonal breeding.

Long-day and short-day breeder examples?

Lecture examples: rabbits are long-day; elk are short-day breeders.

What is induced ovulation?

Mating-related sensory input helps trigger GnRH/LH surge and ovulation.

What stimulates pituitary LH and FSH release?

Pulsatile hypothalamic GnRH.

Where does human fertilization usually occur?

The ampulla of the uterine tube.

What is the role of fimbriae?

Capture the ovulated oocyte near the ovarian surface.

What is the myometrium?

The smooth-muscle layer of the uterus.

At what stage is the primary oocyte arrested?

Prophase I until shortly before ovulation.

At what stage is the ovulated secondary oocyte arrested?

Metaphase II until fertilization.

What is follicular atresia?

Degeneration of recruited follicles that do not become dominant.

What does LH stimulate in theca cells?

Androgen synthesis.

What does FSH stimulate in granulosa cells?

Aromatase-mediated conversion of androgens to estradiol.

What causes the preovulatory LH surge?

Sustained high estradiol switches to positive feedback.

What happens during the follicular phase?

Follicles grow and estradiol promotes endometrial proliferation.

What is the corpus luteum’s main hormone?

Progesterone, with some estrogen.

What is progesterone’s uterine effect?

Supports a secretory endometrium suitable for implantation.

What causes menstruation without pregnancy?

Corpus luteum regression and falling progesterone/estrogen.

What are the three uterine phases?

Menstrual, proliferative, and secretory.

What does kisspeptin activate?

GnRH neurons.

What is the RP3V kisspeptin region associated with?

Estradiol positive feedback and LH surge in rodent models.

What are arcuate KNDy neurons associated with?

Pulsatile GnRH regulation and negative feedback.

What is an antrum in an ovarian follicle?

A fluid-filled cavity that develops as the follicle matures.

How do secretory endometrial glands appear?

Coiled and secretory under progesterone influence.

What do Leydig cells produce?

Testosterone in response to LH.

What do Sertoli cells do?

Support germ cells, form blood-testis barrier, and release inhibin B.

What does inhibin B suppress?

Pituitary FSH secretion.

Where does spermatogenesis occur?

Seminiferous tubules.

Where do sperm mature after leaving the testis?

Epididymis.

Why can anabolic steroids reduce fertility?

Negative feedback suppresses GnRH/LH/FSH and intratesticular testosterone.

What histology suggests suppressed spermatogenesis?

Thinner germ-cell layers and enlarged/open seminiferous lumens.

What is the corpus spongiosum’s anatomical role?

Erectile tissue surrounding the urethra.

What promotes penile erection?

Parasympathetic nitric oxide, smooth-muscle relaxation, and increased inflow.

What is sperm capacitation?

Female-tract changes enabling effective sperm fertilization.

What is the acrosome reaction?

Sperm acrosomal changes enabling penetration of oocyte coverings.

What helps prevent polyspermy?

Cortical changes after sperm–oocyte fusion.

What are the blastocyst’s two main components?

Inner cell mass and trophoblast.

What secretes hCG?

Syncytiotrophoblast.

Why is hCG important early in pregnancy?

Maintains corpus luteum progesterone secretion.

What is decidualization?

Transformation of endometrial stromal cells to support implantation.

What is a hemochorial placenta?

Maternal blood directly contacts trophoblast, as in humans.

How do monotremes reproduce?

Lay eggs and nourish hatchlings with milk.

What distinguishes metatherian reproduction?

Typically shorter gestation and immature young developing while nursing.

What is embryonic diapause?

Temporary delay in embryo development or implantation.

How does placental CRH feedback differ in pregnancy?

Cortisol can promote placental CRH, amplifying late-pregnancy signaling.

What increases uterine responsiveness before labor?

Functional progesterone withdrawal, estrogenic action, and contraction proteins.

What are two contraction-associated proteins?

Oxytocin receptors and connexin 43 gap junctions.

What is the Ferguson reflex?

Cervical stretch increases oxytocin release and uterine contractions.

Prolactin versus oxytocin in lactation?

Prolactin produces milk; oxytocin ejects milk.