Male and Female Reproductive Physiology

Flashcards covering male and female reproductive anatomy, spermatogenesis, oogenesis, hormonal regulation, and the physiology of fertilization.

SEVEN UP

A mnemonic for the male reproductive tract anatomy: Seminiferous tubules, Epididymis, Vas deferens, Ejaculatory duct, Nothing, Urethra, Penis.

Seminiferous tubules

Highly convoluted tubules in the testes, roughly $400 ext{ m}$ long, where spermatogenesis occurs.

Tunica vaginalis

An outpouching of the peritoneal cavity in which the paired gonads (testes) are suspended.

Dartos muscle

A smooth muscle in the scrotum that regulates testicular temperature by contracting to shrivel the skin and decrease surface area for heat loss.

Cremaster muscle

A smooth and skeletal muscle that regulates testicular temperature by contracting to raise the testes toward the body for heat retention.

$$35^{\circ} \text{C}$$

The approximate lower temperature required for proper spermatogenesis (sperm development).

Interstitial cells of Leydig

Cells located in the loose connective tissue surrounding seminiferous tubules that produce testosterone in response to LH.

Sertoli cells

Cells within the seminiferous epithelium that support spermatogenic cells and respond to FSH to stimulate spermatogenesis.

Primary spermatocyte

A diploid cell produced from a spermatogonium that undergoes Meiosis I to become haploid secondary spermatocytes.

Spermiogenesis

The maturation process where haploid spermatids develop into spermatozoa.

Epididymis

An extratesticular duct where sperm reach motility but are kept incapacitated by an acidic pH.

Seminal vesicles

Glands contributing ~70% of semen volume, producing fructose-rich fluid ("sperm food") and semenogelins that coagulate semen upon ejaculation.

Prostate gland

A gland contributing ~30% of semen volume, producing a $Zn^{2+}$- and $HCO_3^-$-rich fluid containing Prostate Specific Antigen (PSA).

Prostate Specific Antigen (PSA)

A protease produced by the prostate gland that liquefies semen in the vagina.

Bulbourethral (Cowper's) glands

Glands that secrete a thick, viscous pre-ejaculatory fluid to cleanse, lubricate, and neutralize urethral acidity.

Corpora cavernosa

The two dorsal columns of spongy, erectile tissue in the penis.

5 \alpha-reductase

The enzyme in the prostate gland responsible for converting testosterone into dihydrotestosterone (DHT), its more potent form.

Oogonia

Female germ or stem cells that develop in the yolk sac and mitotically divide before migrating to the ovarian cortices.

Prophase I

The stage of Meiosis I in which primary oocytes are arrested from birth until puberty.

Metaphase II

The stage of Meiosis II in which the secondary oocyte is arrested after ovulation until sperm entry occurs.

Follicular atresia

The degenerative process by which the ovarian reserve of primordial follicles decreases (e.g., from ~1 million at birth to ~300K at menarche).

Theca interna

A cellular layer of the follicle that produces androstenedione in response to LH stimulation.

Liquor folliculi

Fluid containing growth factors, estrogen, progesterone, and inhibin B secreted by granulosa cells into the antrum.

Graafian follicle

A mature, FSH-dependent follicle where the secondary oocyte and its cumulus cells float freely in the antrum prior to ovulation.

LH surge

Occurs by the 14th day of the menstrual cycle due to high plasma estrogen; it triggers the resumption of meiosis and ovulation.

Ampulla

The specific region of the fallopian tube (oviduct) where fertilization usually occurs within 1-2 days of ovulation.

Corpus luteum

A temporary endocrine gland formed from a collapsed Graafian follicle; it produces progesterone and estrogen.

Human chorionic gonadotropin (hCG)

The hormone responsible for maintaining the corpus luteum during early pregnancy.

Endometrium

The inner glandular and vascular layer of the uterus where an embryo implants within ~5-7 days of fertilization.