Male Reproductive System
Testes Primary reproductive organs Male gonads
Structures of the Testes Tunica Albuginea Fibrous connective tissue surrounding testes Septa-divisions Seminiferoud Tubules: Sperm-forming factories Interstitial Cells Produces testosterone
Duct System Epididymis Highly coiled tube First part of the male duct system Temporary storage site for immature sperm that enter it from the testes Sperm mature along the trip (20 days) Walls contract to expel sperm Ductus Deferens (carrying away) or Vas Deferens Runs upward from the epididymis Empties into the ejaculatory duct Main Function: Propel live sperm from their storage sites into urethra Vasectomy Cuts or cauterizes the vas deferens
Urethra: Three named regions Prostatic Urethra Surrounded by the prostate gland Membranous Urethra Spanning the distance from prostatic urethra to penis Spongy (penile) Urethra Running the length of the penis Male urethra carries both urine and sperm Bladder sphincter constricts prevents passage of urine Also prevents sperm from entering bladder
3 Accessory Glands & Semen Produce the bulk of semen Semen is sperm containing fluid 1. Seminal Vesicles Located at the base of the bladder Produce 60% of the fluid volume of semen Thick, yellowish liquid Rich in Fructose Vitamin C Nourishes and activates the sperm
Accessory Glands continued 2.Prostate Gland – size of a chestnut Secretes a milky fluid that plays a role in activating, nourishes & protects sperm 3.Bulbourethral Glands – pea sized Produces a thick clear mucus that drains into the penile urethra This is the first to pass down the urethra Cleanses the urethra of traces of acidic urine Lubricant during sexual intercourse
Semen Milky white, somewhat sticky mixture of sperm and accessory gland secretions Contains chemicals that protect the sperm and aid in their movement About 2-5 ml and between 50-130 million sperm in each milliliter
External Genitalia Scrotum Divided sac of skin that hangs outside the abdominal cavity, between the legs and at the root of the penis Provides testes with temperature below body temperature Viable sperm cannot be produced at body temperature
Spongy tissue that fills with blood and becomes rigid (erection) Penis Designed to deliver sperm into female reproductive tract Shaft Ends in an enlarged tip (Glans Penis) Skin covering is loose and folds downward to form a cuff of skin (prepuce) or foreskin Inside are three elongated areas of erectile tissue Spongy tissue that fills with blood and becomes rigid (erection)
Sperm Anatomy
Male Reproductive Functions Chief Role Produce sperm and the hormone testosterone Spermatogenesis – sperm production Begins at puberty Everyday a man makes millions of sperm Spermiogenesis Last stage of sperm development Compacted into head, midpiece and tail Sperm head Contains DNA Acrosome – anterior to nucleus Breaks down & releases enzymes that help the sperm penetrate through the follicle cells that surround the egg.