II. Anatomy
- Testicular size (length)
- Images
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
III. Physiology: Development
- Gestation 5.5 to 8 weeks
- Gonadal differentiation is triggered by Testis determining factor Protein (SRY gene)
- Primordial gonad differentiates into Testicle
- Testes develop from mesenchymal tissue within urogenital ridge (gonadal ridge)
- Gonadal agenesis occurs if primordial germ cells fail to migrate into urogenital ridge
- Gonadal differentiation is triggered by Testis determining factor Protein (SRY gene)
- Gestation 8 to 15 weeks
- Transabdominal migration of Testicle from gonadal ridge to lumbosacral region of developing Kidney
- Testicles migrate to the inguinal ring as the cranial suspensory ligament regresses
- Gestation 10 to 11 weeks: Androgen secretion
- Leydig cells produce Testosterone and Insulin-like peptide 3
- Wolffian duct (Mesonephric duct) differentiation
- Epididymis
- Vas deferense
- Seminal Vessicles
- Gestation 32-36: Testes descend into Scrotum
IV. Physiology: Function
-
Pituitary Gland
- Releases Luteinizing Hormone (LH)
- Testes
- Leydig cells in Testes releases Testosterone in response to LH release