Male Reproductive System
Labeling TestisEpididymis ScrotumVas deferens ProstateSeminal vesicle Urinary bladder Rectum PenisCowper’s Glands Urethra
Testes Testes (2 of them) – Male gonads – Seminiferous tubules Site of sperm formation in the testes FSH stimulates sperm production – Leydig cells (interstitial cells) Scattered among the seminiferous tubules Produce testosterone LH stimulates testosterone production – Epididymis Tube in the testes where sperm gain mobility Suspended in the scrotum
Urethra Tube that extends from the bladder, through the penis, to the outside of the body Carries semen and urine 5-7 inches long in male
Penis External male reproductive organ Glans penis - enlarged structure on the end of the penis – This is covered by the prepuce or foreskin – The foreskin is removed in a procedure called circumcision Penis is made of spongy, erectile tissue – During sexual arousal, the erectile tissue fills with blood from the arteries, causing an erection Functions – male organ of copulation/intercourse – Elimination of urine from the bladder
Ejaculation The male gonads, or testes, consist of highly coiled tubes surrounded by connective tissue Sperm form in these seminiferous tubules From the seminiferous tubules of a testis, sperm pass into the coiled tubules of the epididymis During ejaculation, sperm are propelled through the muscular vas deferens and the ejaculatory duct, and then exit the penis through the urethra
Semen Three sets of accessory glands add secretions to the semen, the fluid that is ejaculated – The two seminal vesicles contribute about 60% of the total volume of semen – The prostate gland secretes its thin milky fluid containing enzymes and sperm nourishment directly into the urethra – The Cowper’s gland secretes a clear mucus before ejaculation that neutralizes acidic urine remaining in the urethra
The Male Hormone Pattern
Reproductive Hormones Androgen: Testosterone – Primary sex characteristics development of the vas deferens and other ducts development of the external reproductive structures sperm production – Secondary sex characteristics Deeper voice Axillary and pubic hair Chest and facial hair Lengthen bones Increased size of testes for sperm production
Reproductive Hormones Gonadotropic Hormones ◦ Released from the Anterior Pituitary Gland Follicle-Stimulating Hormone (FSH) stimulates production of sperm Luteinizing Hormone (LH) stimulates secretion of testosterone
The Male Pattern
The male hormone pattern is continuous. The principle male sex hormones are androgens specifically testosterone. Gonadotropin-Releasing Hormone (GnRH) – Produced by the hypothalamus – Regulates FSH and LH levels – Controlled by negative feedback from FSH and LH
Copyright Pearson Prentice Hall Sperm Production Regulation
Spermatogenesis Process of sperm production Continuous process that begins at puberty and continues through life LH induces Leydig cells to produce testosterone Together with FSH, testoterone stimulates sperm production in the seminiferous tubules.
Testicular Cancer Cancer of the testicles Frequent in men Highly malignant and spreads quickly Treatment ◦ Orchiectomy, radiation ACS ◦ American Cancer Society ◦ Recommends STE ◦ Self testicular exam