Forms in testis (spermatogenesis). Primordial germ cells differentiate into spermatogonia (fetal and infant testis contains spermatogonia). In puberty increased testosterone starts meiosis leading to sperm formation
Spermatogonia will differentiate into primary spermatocyte which will undergo meiosis and produce a secondary spermatocyte. The secondary spermatocyte will undergo meiosis again to produce spermatid which will differentiate into sperm (4 cells)
mutations in androgen receptor and during development cells do not respond to androgens. Female appearance , may lack ovaries and uterus or menstruation , frequently sterile
How do androgens work in androgen dependent cells?
In 6th week we have undifferentiated developing gonads. When SRY gene (sex determining region) is activated testis is developed with androgen receptors
In week 7 there is a lack of androgen receptors and therefore there is a lack of development of mullerian or wolffian ducts. The body thinks there is no testosterone and so androgens increase leading to no effect and so the testosterone aromatase leading to estrogens which is what causes feminine appearance
Hypothalamus releases gonadotropin releasing hormone which stimulates hypophysis which releases FSH which stimulates setoli cells (mature germ cells) which is absorbed by ABP. Hypophysis also releases LH which stimulate leydig cells which releases testosterone which stimulate sertoli cell
Parasympathetic NS releases nitric oxide in endothelial cell which diffuses to smooth muscle cell which triggers GTP to cGMP conversion leading to vasodilation and erection