Human Reproduction - Male Reproductive System

The male reproductive system is located in the pelvis region and includes a pair of testes, accessory ducts, glands, and the external genitalia.

The testes are situated outside the abdominal cavity within a pouch called the scrotum, which maintains a temperature $2-2.5^\circ C$ lower than the internal body temperature, essential for spermatogenesis.

Each testis contains about $250$ testicular lobules, each housing $1-3$ highly coiled seminiferous tubules where sperm are produced.

Seminiferous tubules are lined by two types of cells: male germ cells (spermatogonia, $2n$) and Sertoli cells (nurturing cells).

Leydig cells (interstitial cells) are present in the regions outside the seminiferous tubules and synthesize/secrete testicular hormones called androgens (e.g., Testosterone).

The male accessory ducts include the rete testis, vasa efferentia, epididymis, and vas deferens. The pathway of sperm is: Seminiferous tubules $\rightarrow$ Rete testis $\rightarrow$ Vasa efferentia $\rightarrow$ Epididymis $\rightarrow$ Vas deferens $\rightarrow$ Ejaculatory duct $\rightarrow$ Urethra.

The male accessory glands (seminal vesicles, prostate, and bulbourethral glands) secrete seminal plasma, which is rich in fructose, $Ca^{2+}$, and specific enzymes.