MALE REPRODUCTIVE GLAND

By J9

TESTES Located in the scrotum Secrete hormone known as androgen;

most important of which is testosterone Have an exocrine part, Seminiferous

tubules (tightly coiled) and endocrine part, intersitial or Leydig cells (clusters)

Leydig cells Synthesise and secrete testosterone Located in the interstitial tissue between

the convuluted seminiferous tubules Occurs in clusters, which are variable in

size and richly supplied by capillaries Its cytoplasm is strongly acidophilic and

finely granular The nucleus is large, round and often

located eccentric in the cell

General effects of the testosteroneAnabolic

Growth of muscle mass and strength

Increased bone density and strength

Linear growthBone maturation

Androgenic (Virilizing)Maturation of sex organs (part. Penis)

Formation of scrotum in the fetus

Deepening of voice (sec. sex charac.)

Growth of beard and axillary hair (sec. sex charac.)

...cont. testosterone Testosterone increases sharply at

puberty Essential for the production of sperm Production of testosterone is controlled

by the release of luteinizing hormone (LH)

Hypothalamus GnRH Pituitary

LHTestesTestosterone

Sertoli cells ‘nurse’ cell of the testes Part of the seminiferous tubule Activated by follicle-stimulating

hormone and has FSH-receptor on its membranes.

Estradiol and Inhibin – hormone secreted

EstradiolPrevent apoptosis (death of cells) of

germ cellsInhibin

Inhibit production of FSH

Arrows shows the location of the leydig cells

1 Lumen of Tubulus seminiferus contortus2 spermatids3 spermatocytes4 spermatogonia5 Sertoli cell6 Myofibroblasts7 Leydig cells8 capillaries

TESTIS