Male Reproductive System

Male Reproductive System

A group of organs working together to produce gametes (sperm) and reproductive hormones, store and transport sperm cells, and deliver them to the female reproductive tract.

Penis

The external male organ used for urination and sexual intercourse, consisting of the root, body, and glans.

Root of Penis

The base of the penis that attaches to the wall of the abdomen.

Body of Penis

The main length of the penis, also known as the shaft, made up of spongy, erectile tissues that fill with blood during sexual arousal to cause an erection.

Glans Penis

The rounded, sensitive tip or head of the penis that houses the opening of the urethra.

Scrotum

The loose, pouch

Scrotal Temperature Regulation

The muscular dynamic of contracting or relaxing to keep the testicles roughly $2\text{ to }3^\circ\text{F}$ cooler than normal body temperature for healthy sperm production.

Testicles

The male gonads responsible for producing testosterone and generating millions of sperm cells daily.

Epididymis

A coiled tube attached tightly to the back of each testicle that serves as a storage nursery where sperm mature and develop motility.

Vas Deferens

The long tube that carries sperm from the epididymis to the urethra during ejaculation.

Urethra

The terminal tube running through the penis that carries both urine and semen out of the body at separate times.

Seminal Vesicles

Accessory glands that produce an alkaline, sugary fluid to provide energy and nourishment to sperm cells.

Prostate Gland

A walnut

Bulbourethral Glands

Accessory glands that secrete a lubricating and neutralizing fluid to protect sperm from residual acidic urine in the urethra.

Spermatogenesis

The complete biological process by which immature diploid germ cells develop into mature, functional haploid sperm.

Spermatogonia

Diploid stem cells ($2n$) located at the outer edge of the tubule wall that divide rapidly via mitosis to maintain a constant germ line supply.

Spermatocytes

The germ line cells that undergo meiosis to cut the chromosome count from 46 to 23 ($1n$).

Spermatids

The immediate, non

Spermiogenesis

The final streamlining and maturation phase where a spermatid grows a tail, packs mitochondria into its midpiece, and forms an acrosome cap.

Acrosome

A specialized enzyme

Sertoli Cells

Supporting nurse cells spanning from the basement membrane to the lumen of seminiferous tubules that nourish sperm, control survival, and form the blood

Blood

Testis Barrier

Gonadotropin

Releasing Hormone

Follicle

Stimulating Hormone

Androgen

Binding Protein

Luteinizing Hormone

An anterior pituitary hormone that binds to Leydig cells to stimulate the synthesis and release of testosterone.

Leydig Cells

Interstitial cells located in the connective tissue spaces between seminiferous tubules that produce testosterone.

Testosterone

The primary male androgen vital for spermatogenesis, muscle/bone growth, and the development of secondary sex characteristics.

Inhibin

A peptide hormone released by Sertoli cells that acts as a negative feedback signal to inhibit FSH release when sperm production is sufficient.