Male Reproductive System & Gametogenesis

Vocabulary flashcards covering key terms from lecture on human reproduction, gametogenesis, male reproductive anatomy, embryologic ducts, and hormonal regulation.

Diploid (2n)

Cell state containing two complete sets of chromosomes—one from each parent (46 total in humans).

Haploid (n)

Cell state containing one set of chromosomes (23 in humans); characteristic of gametes.

Chromosome

DNA molecule with associated proteins that carries genetic information; humans have 23 pairs.

Karyotype

Laboratory image showing the complete set of an individual’s chromosomes arranged in pairs.

Gamete

Haploid sex cell (sperm or egg) containing 23 chromosomes.

Zygote

Diploid cell formed by fusion of a sperm and an egg at fertilization.

Meiosis

Specialized double division in gonads that halves chromosome number to produce gametes.

Mitosis

Standard cell division producing two genetically identical diploid daughter cells.

Gonads

Primary reproductive organs that produce gametes and hormones (testes or ovaries).

Genitalia

External reproductive structures involved in gamete transfer.

Oocyte

Immature female gamete developing in the ovary prior to ovulation.

Ovum (Egg)

Mature female gamete capable of being fertilized by sperm.

Spermatocyte

Developing male germ cell undergoing meiosis inside the testes.

Sperm

Mature male gamete consisting of head, midpiece, and flagellum.

Semen

Ejaculated fluid composed of sperm plus secretions from accessory glands.

Seminiferous Tubules

Highly coiled tubes inside testes where sperm production occurs.

Epididymis

~23-ft coiled duct atop each testis where sperm mature and are stored.

Ductus (Vas) Deferens

Muscular tube transporting stored sperm from epididymis toward ejaculatory duct.

Ampulla (of ductus deferens)

Expanded distal region of ductus deferens that stores sperm before ejaculation.

Seminal Vesicles

Paired glands posterior to bladder that add fructose, prostaglandins, and fibrinogen blocker to semen and trigger flagellar motility.

Prostate Gland

Donut-shaped gland encircling urethra; contributes acidic prostatic fluid with seminal plasma and zinc.

Bulbourethral (Cowper’s) Glands

Small glands near base of penis that secrete alkaline mucus to neutralize urethra and lubricate glans.

Spermatogonia

Stem cells lining seminiferous tubules that give rise to sperm.

Spermatogenesis

Overall process of sperm formation from spermatogonia to spermatozoa.

Spermatid

Haploid cell produced by meiosis II that will remodel into a sperm.

Spermiogenesis

Final maturation step where spermatids shed excess cytoplasm and form heads, midpieces, and tails.

Flagellum

Long whip-like tail of sperm that propels it through fluid.

Mitochondrial Collar (Midpiece)

Region packed with mitochondria supplying ATP for flagellar movement.

Acrosome (Acrosomal Cap)

Enzyme-filled cap over sperm head that helps penetrate egg coverings.

Cryptorchidism

Condition in which one or both testes fail to descend into the scrotum.

SRY Gene

Y-chromosome gene encoding testes-determining factor that initiates male development.

Testes-Determining Factor (TDF)

Protein produced by SRY gene that directs indifferent gonad to form testes.

Mullerian Ducts

Embryonic ducts that develop into female reproductive tract unless inhibited.

Wolffian Ducts

Embryonic ducts that develop into male reproductive tract when stimulated by testosterone.

Mullerian Inhibiting Factor (MIF)

Hormone from fetal testes that causes regression of Mullerian ducts.

Peristalsis

Wave-like smooth-muscle contractions that propel sperm through ducts.

Seminal Plasma

Component of prostatic fluid containing enzymes and antimicrobial factors.

Gonadotropin-Releasing Hormone (GnRH)

Hypothalamic hormone that triggers anterior pituitary release of FSH and LH.

Follicle-Stimulating Hormone (FSH)

Pituitary hormone that stimulates sustentacular (Sertoli) cells and promotes spermatogenesis.

Luteinizing Hormone (LH)

Pituitary hormone that stimulates interstitial (Leydig) cells to secrete testosterone.

Interstitial (Leydig) Cells

Cells between seminiferous tubules that produce androgens, chiefly testosterone.

Sustentacular (Sertoli) Cells

Support cells within seminiferous tubules that nourish developing sperm and secrete inhibin.

Inhibin

Hormone from sustentacular cells that provides negative feedback on FSH release.

Androgen (Testosterone)

Primary male sex hormone responsible for spermatogenesis, muscle growth, and secondary sexual traits.