Male Reproductive System

• The male reproductive system includes gonads, reproductive pathways, glands, and the penis.

Gonads (Testicles)

• Testicles are the male gonads, containing seminiferous tubules where sperm production occurs.
• Spermatogonia, located in the walls of the seminiferous tubules, produce sperm.
• Connective tissue between the tubules produces androgens (male sex hormones).
• Testicles are located outside the body in a sac of skin called the scrotum.

Reproductive Pathways

• Epididymis: a duct formed by the seminiferous tubules, where sperm mature.
• Vas deferens: continuation of the epididymis, ascends into the abdomen and stores sperm until they leave the body, up to 42 days.
• Urethra: belongs to both the urinary and reproductive systems, housed inside the penis.

Glands

• Accessory glands in the male reproductive system secrete fluids that mix with sperm to form semen.
• Seminal vesicles: produce spermatic fluid containing glucose, which nourishes sperm.
• Prostate: Located under the urinary bladder, produces prostatic fluid that protects sperm from the acidity of the vagina.
• Cowper's glands: secrete lubricant to facilitate sexual intercourse.

Penis

• The penis is the male copulatory organ.
• It contains two spongy tissues called corpora cavernosa and the corpus spongiosum.
• The corpus spongiosum surrounds the urethra and widens to form the glans, covered by the foreskin.
• During erection, blood fills the corpora cavernosa, causing the penis to enlarge and harden.

Male Gametogenesis: Spermatogenesis

• Spermatogenesis is the process of sperm cell production in the seminiferous tubules of the testicles.
• Spermatogenesis occurs in three stages within the seminiferous tubules:
  • Growth and multiplication of spermatogonia (sperm cells).
  • Meiosis: a cell with 46 chromosomes divides to produce 4 cells with 23 chromosomes each.
  • Maturation: the four cells transform into spermatozoa through lengthening, reducing cell volume, losing cytoplasm, and forming a flagellum.

Male Gamete, Sperm

• Head: contains the nucleus with 23 chromosomes and an acrosome
• Acrosome: a cellular organ that secretes substances and helps with egg fertilization.
• Tail: provides motion.
• Neck: located between the head and tail, containing numerous mitochondria that provide energy for movement and a centriole that helps with movement.