Male Reproductive System and Human Development Lecture Notes

This set of flashcards covers the anatomy and physiology of the male reproductive system, hormonal regulation, sperm development, fertilization, and early stages of human embryonic development.

Spermatogonia

Germ cells that continually produce sperm through mitosis and meiosis.

Sustentacular cells (Sertoli cells)

Cells that create the blood-testis barrier, nourish developing sperm, and release the hormone inhibin to inhibit FSH secretion when sperm count is high.

Interstitial cells (Leydig cells)

Cells surrounding the seminiferous tubules that produce androgens, specifically testosterone, in response to luteinizing hormone (LH).

Tunica albuginea

A fibrous capsule that enters each testis and subdivides the internal space into approximately $250$ lobules.

Seminiferous tubules

Structures within the lobules of the testes where sperm development occurs, with each lobule containing $1$ to $4$ of these tubules.

Gonadotropin-releasing hormone (GnRH)

A hormone secreted by the hypothalamus that initiates puberty by stimulating the anterior pituitary.

Follicle stimulating hormone (FSH)

A gonadotropin that stimulates sustentacular cells to secrete androgen-binding protein (ABP).

Luteinizing hormone (LH)

A gonadotropin that stimulates interstitial cells to secrete testosterone.

Androgen-binding protein (ABP)

A protein that binds androgens to maintain high concentrations of them within the seminiferous tubules.

Acrosome cap

A structure on the sperm head contains digestive enzymes necessary for fertilization.

Epididymis

A duct where spermatozoa enter to complete development and are stored until ejaculation.

Ductus deferens (vas deferens)

A thick-walled tube that propels sperm from the epididymis to the ejaculatory duct.

Seminal vesicles

Glands that contribute about $70\%$ of semen volume, providing alkaline fluid, fructose, prostaglandins, and a clotting enzyme.

PSA (Prostate Specific Antigen)

An enzyme secreted by the prostate gland that helps liquefy semen $15$ to $30\,minutes$ following ejaculation.

Bulbourethral glands

Glands that produce clear, viscous mucin that protects the urethra and serves as a lubricant (pre-ejaculate).

Corpora cavernosa

Paired cylindrical erectile bodies within the shaft of the penis.

Capacitation

The final maturation process of spermatozoa in the female reproductive tract that may take up to $7\,hours$ and renders them capable of fertilization.

Zona reaction

A process where cortical granules release enzymes to modify zona pellucida receptors to prevent more than one sperm from binding.

Polyspermy

A condition where the oocyte is penetrated by more than one sperm, leading to embryonic death.

Zygote

A fertilized egg that consists of $2$ or more cells and has a restored diploid number of $46$ chromosomes.

Blastomeres

Cells arising from the cleavage divisions of the zygote.

Morula

A developmental stage consisting of $12$ to $15$ totipotent blastomeres, appearing like a fruit from a mulberry tree.

Embryoblast (Inner cell mass)

A mass of cells within the blastocyst that eventually gives rise to the definitive structures of the fetus.

Trophoblasts

Cells forming the outer layer of the blastocyst that provide nutrients and develop into a large part of the placenta.

Placenta previa

A condition where implantation occurs over the opening of the cervix, which can lead to premature detachment of the placenta.

Ectopic pregnancy

An extrauterine implantation that usually occurs in the fallopian tube and is a main cause of maternal death during the first trimester.