HUMAN REPRODUCTIVE SYSTEM

HUMAN REPRODUCTIVE SYSTEM

1. Male Reproductive System

It consists of paired testes, Accessory ducts, Accessory glands & external genitalia (penis).

a. Paired testes

◆ Primary sexorgans that produce sperms & testosterone.

◆ Testes are formed within the abdomen. Soon after the birth or at the 8th month of pregnancy they descent into the scrotal sac (scrotum) through inguinalcanal.

◆ The low temperature (2-2.50 C less than the body temperature) of scrotum helps for proper functioning of testes and for spermatogenesis.

◆  Each testis is oval shaped. Length 4-5 cm, width: 2-3 cm.

◆  Each testis has about 250 testicular lobules.

◆  Each lobule contains 1-3 coiled seminiferous tubules.

◆  Seminiferous tubule is lined internally with spermatogonia  (male germ cells) & Sertoli cells (supportingcells).

◆ Sertoli cells give shape and nourishment to developing spermatogonia.

◆ The regions outside the seminiferous tubules (interstitial spaces) contain small blood vessels, interstitial cells (Leydig cells) and immunologically competent cells.

◆  Leydig cells secrete testicular hormones (androgens).

b. Accessory ducts (Duct system)

◆  Include rete testis, vasa efferentia, epididymis & vas deferens. They conduct spermsfrom testis as follows:

◆ Seminiferous tubules → rete testis (irregular cavities) → vasa efferentia (series of fine tubules) → epididymis (stores sperms temporarily) → vas deferens → join with duct of seminal vesicle to form common ejaculatory duct → urethra →urethral meatus.

◆ Urethra receives ducts of prostate and Cowper’s glan

C. Accessory glands

◆ Include a prostate gland, a pair of seminal vesicles and a pair of Cowper’s glands (bulbo-urethral glands).

◆ Their collective secretion (seminal plasma) is rich in fructose, Ca and enzymes.

◆  Seminal plasma + sperms →semen.

◆ Functions of seminal plasma:

◆  Helps for transporting sperms.

◆  Supplies nutrients to sperms.

◆  Provides alkalinity to counteract the acidity of uterus.

◆ Secretions of Cowper’s glands lubricate the penis.

◆  Secretions of epididymis, vas deferens, seminal vesicle & prostate help for maturation and motility of sperms.

d. Penis (external genitalia)

◆  It is a copulatory organ made of erectile spongy tissue.

◆ When spongy tissue is filled with blood, the penis erects. It facilitates insemination.

◆  The cone-shaped tip of the penis is called glans penis. It is covered by prepuce (foreskin).