Spermatogenesis

1ry sex organs vs 2ry sex organs of male reproductive system

1ry sex organs:

Testes → Interstitial cells of leydig (Testosterone) , Seminefrous tubules (sertoli cells of spermatogonia (spermatogenesis)

2ry sex organs: External genitalia, seminal vesicles, prostate, duct system

Functions of sertoli cells (Structural, Barrier, Nutrient, Regulation, Phagocytic, Fluid)

1. Structural (physical) support → surrounds developing germ cells in seminefrous tubules forming nuturing environ

2. Tight junction form blood-testis barrier → separates basal from liminal compartment to protect germ cells from immune system (prevents autoimmune reaction)

3. Nutritional (and metabolic support) to developing sperm → transfers glucose, lactate, amino acids, phagocytes residual cytoplasm (spermiogenesis)

4. Endocrine function by responding to FSH and Testosterone →

• ABP (androgen binding protein) concentrates testosterones in tubules for spermatogenesis

• Inhibin B inhibits FSH secretion

• Anti mullerian hormone (AMH, fetal life) regresses Mullerian ducts in male embryo

5. Spermatogenesis regulation as coordinates germ cell maturation by release growth factors and cytokines

6. Phagocytic role by removing apoptotic germ cells and cytoplasmic remnants ensures proper sperm developments

7. Secretes tubular fluid → helps transport sperm through seminefrous tubules

Serotoli cells produce hormones and their effects

1. Androgen binding proteins ABP → concentrates testosterones in tubules for spermatogenesis

2. Mullerian inhibiting factor → regression of mullerian duct prevents forming female genital tract

3. Estrogen (small amount)

4. Inhibin → FSH inhibition

Male reproductive physiology

1. Before birth masculinizes reproduction tract and external genitalia

2. Testes descent

3. Ceases at birth

4. Returns at puberty testicular leydig cells secrete testosterone

5. Testes descend and pass out of abdominal cavity

Star protein needed for cholesterol transport into mitochondria rate limiting step (protein in outer mitochondrial membrane of steroid producing cells (Leydig cells, adrenal cortex, ovarian theca/luteal cells))

Puberty in male

• Usually 10-14 yrs old

• Endocrine, physical and behavioural

• Leydig cells awake

• Leydig cells stay awake for about 50 years

• Leydig cells response to LH decrease by age

• Leydig cells help in oxytocin release which allow seminiferous tubules and epididymis motility

• Spermatogenesis

• Accessory sex glands enlarge and become secretory

• Penis and scrotum enlarge

• Testosterone 25% decrease in evening