Male Reproductive System PDF

WEEK 15: MALE REPRODUCTIVE SYSTEM 3. TARGET ORGANS & HORMONES IN MALES: A. TESTES Anatomy & Physiology: The Human Reproductive LH stimulates Leydig cells to produce System...

WEEK 15: MALE REPRODUCTIVE SYSTEM 3. TARGET ORGANS & HORMONES IN MALES: A. TESTES Anatomy & Physiology: The Human Reproductive LH stimulates Leydig cells to produce System testosterone, the primary male sex hormone. FSH acts on Sertoli cells to support REPRODUCTIVE SYSTEM spermatogenesis (sperm production) Composed of organs grouped together for one TESTOSTERONE & INHIBIN provide feedback (1) common function to suppress GnRH, LH, & FSH secretion to - To produce or multiply species of the maintain hormonal balance. same kind. The purpose is to ensure the “survival of the (INSERT SLIDE 14 TO 15 PICTURE) species” Both male and female reproductive organs MALE REPRODUCTIVE ANATOMY & PHYSIOLOGY have internal and external structures. 1. Testis The primary reproductive organs are the 2. Epididymis gonads (ovaries & testes), which are 3. Vas Deferens responsible for gamete (sperm & egg cell) and 4. Seminal Vesicle hormone production. 5. Prostate 6. Bulbourethral (INSERT PICTURE SLIDE 6) 7. Ejaculatory Duct SEXUAL DIFFERENTIATION: INTERNAL EMBRYONIC 8. Urethra DEVELOPMENT 9. Penis BIPOTENTIAL TISSUES: Genes & Hormones Direct Differentiation (INSERT SLIDE 17 TO 18 PICTURE) GONAD —> Testis or Ovary WOLFFIAN DUCT —> Vas deferens, TESTES MULLERIAN DUCT —> Oviduct Each testis is connected to the trunk via the spermatic cord, which houses: (INSERT SLIDE 8 TO 11 PICTURE) 1. Blood Vessels 2. Nerves REGULATION OF REPRODUCTION: GENERAL 3. Ductus / Vas Deferens PATHWAYS 1. HYPOTHALAMUS: “PULSE GENERATOR” COVERING OF THE TESTES The hypothalamus acts as a “pulse generator,” 1. TUNICA ALBUGINEA releasing Gonadotropin-Releasing Hormone Capsule that surrounds each testis (GnRH) in a pulsatile manner. 2. SEPTA These pulses are critical for stimulating the Extensions of the capsule that extend pituitary gland to release its hormones. into the testis and divide it into lobules The frequency and amplitude of GnRH pulses vary depending on the stage of the reproductive EACH LOBULE CONTAINS ONE (1) TO FOUR (4) cycle or development state (e.g., puberty, SEMINIFEROUS TUBULES menstrual cycle). 1. Tightly coiled structures 2. GnRH AND THE ANTERIOR PITUITARY 2. Function as sperm-forming factories GnRH travels to the anterior pituitary via the 3. Empty sperm into the rete testis hypothalamic-hypophyseal portal system. The ANTERIOR PITUITARY responds by SPERM travels from the rete testis to the epididymis secreting two (2) key gonadotropins: INTERSTITIAL CELLS in the seminiferous tubules 1. LUTEINIZING HORMONE (LH) produce androgens such as testosterone Stimulates hormone production and key reproductive processes. (INSERT SLIDE 20 PICTURE) 2. FOLLICLE STIMULATING HORMONE (FSH) Supports gamete development (eggs in females, sperm in males). STRUCTURE OF THE GONADS: 1. SEPTAE COMPOSED OF 3 CYLINDRICAL COLUMNS OF A partition formed inside the testes ERECTILE TISSUE: 2. LOBULES 1. TWO CORPORA CAVERNOSA (PLURAL, Compartments formed by the septae SINGULAR: “CORPUS CAVERNOSUM”) These are the paired, larger columns located 3. SEMINIFEROUS TUBULES on the dorsal (top) side of the penis. Actual site of spermatogenesis; formed by two They run parallel along most of the length of the (2) types of cell. penis. 1. SPERMATOGENIC CELLS Their primary role is to fill with blood, causing - Includes spermatids, the penis to become rigid during an erection. spermatogonia, spermatocytes 2. ONE (1) CORPUS SPONGIOSUM 2. SUSTENTACULAR (SERTOLI) CELLS This is a single, smaller column located on the - Provide nourishment for the ventral (underside) side of the penis. germinal sperm It surrounds the urethra, the tube through which urine and semen pass. INTERSTITIAL CELL OF LEYDIG During an erection, the corpus spongiosum Secretes male sex hormone - “testosterone” also fills with blood but remains slightly less rigid to prevent compression of the urethra, (INSERT SLIDE 24 TO 25) allowing ejaculation to occur. SCROTUM ❖ Male organ of copulation that delivers sperm A sac or pouch like structure that hangs from into the female the root of the penis, composed of loosed skin, ❖ Internally there are three (3) areas of spongy superficial fascia, and muscles. erectile tissue around the urethra ❖ Erection occur when this erectile tissue fills with VERTICAL SEPTUM blood during sexual excitement Divides the scrotum into two (2) sacs, containing a single testis function to support and (INSERT SLIDE 30 TO 33 PICTURE) protect the testes and maintain the temperature of the testes at about 35°C SERTOLI CELLS Form blood-testes barrier: THE PENIS Prevents autoimmune destruction of 1. ROOT OF THE PENIS sperm. Attached portion to the abdominal wall Produce FAS ligand which binds to the 2. BODY OF THE PENIS FAS receptor on surface to T Composed of erectile tissue lymphocytes, triggering apoptosis of T lymphocytes. 3. GLANS PENIS Prevents immune attack. Cone-shaped terminal portion of the penis, consist of the following structure: Secrete inhibin. 1. Corona 2. External Urethral Meatus Phagocytize residual bodies: 3. Prepuce (Foreskin) May transmit information molecules from 4. Frenulum germ cells to Sartori cells. Secrete Androgen-Binding Protein (ABP): 4. PENIS is the main copulatory organ of the male Binds to testosterone and concentrates reproductive system. testosterone in the tubules. SPERMIOGENESIS Maturation of spermatozoa. Phagocytosis of cytoplasm by the Sertoli cells. Cytoplasm is eliminated.