Male genital system.pdf

 (The Testis) Each testis is surrounded by a dense connective tissue capsule, the tunica albuginea, from this capsule, septa Divide the testis into about 250 pyramidal compartments or testicular lobules Each lobule contains connective tissue with endocrine interstitial cells...

 (The Testis) Each testis is surrounded by a dense connective tissue capsule, the tunica albuginea, from this capsule, septa Divide the testis into about 250 pyramidal compartments or testicular lobules Each lobule contains connective tissue with endocrine interstitial cells (or Leydig cells) secreting testosterone , and one to four highly convoluted seminiferous tubules in which sperm production occurs. Functions: 1- Production of the spermatozoa. 2- Production of the male sex hormones mainly testosterone The germinal epithelium is mainly formed of sex cells and a few supporting cells (Sertoli cell). These cells lie on a basement membrane which is surrounded by a connective tissue sheath. A) Sex cells (Spermatogenic cells) : These cells form 4-8 layers. They differentiate progressively from the base to the lumen of the seminiferous tubule.  spermatogonia, primary spermatocytes, secondary spermatocytes spermatids These cells by (spermiogenesis) change to spermatozoa. B) Sertoli cells: LM: Sertoli cells are tall columnar cells with their bases resting on the basement membrane. Their apical cell membranes are highly folded and project into the lumina of the seminiferous tubules. These cells have pale irregular nucleus with a large nucleolus. The lateral cell membranes of adjacent Sertoli cells form occluding junctions with each other. Thus, the occluding junctions of these cells establish a blood-testis barrier protecting the developing gametes from the immune system. Sertoli cells perform the following functions: 1. Physical and nutritional support of the developing germ cells. 2. Phagocytosis of cytoplasm eliminated during spermiogenesis. 3. Establishment of a blood-testis barrier by the formation of zonulae occludentes between adjacent Sertoli cells.  The interstitial connective tissue is loose and contains macrophages, fibroblasts and mast cells. It also contains important clusters of cells called interstitial cells of leydig. Interstitial cells of leydig L.M: Interstitial cells of Leydig are polyhedral The cytoplasm is pale, acidophilic and vacuolated due to dissolved fat droplets. They have a single rounded nucleus.