Connected series of organs and glands that produce and nurture sex cells and transport them to sites of fertilization.

 GONADS: reproductive organs o Male: testes o Female: ovaries  GAMETES: reproductive cells that have one set of genetic instructions on 23 chromosomes o Male: sperm o Female: ova (egg)  FERTILIZATION: union of egg and sperm to form a zygote

 TESTES o Surrounded by a saclike scrotum (protects and regulates temperature of testes) o Seminiferous tubules formed from lobules of fibrous capsule that surround each testis Spermatogenic cells line these and produce sperm cells Deliver sperm to epididymis Interstitial cells are also found here and produce male sex hormones Epithelial cells found here can give rise to testicular cancer

 EPIDIDYMIS Highly coiled tube about 6m long Temporary storage for immature sperm Sperm travel for about 20 days through it maturing and gaining ability to swim When male is stimulated, walls contract and expel sperm to vas deferens

 VAS DEFERENS Muscular tube that passes from testis through abdominal cavity & ends behind urinary bladder Unites with ejaculatory duct and empties into the urethra Vasectomy o vas deferens is cut or cauterized to stop flow of sperm o Sperm is still produced but can no longer reach body exterior o Sperm will die and be reabsorbed  URETHRA extends from base of urinary bladder to tip of penis Urine and sperm pass through here but never at same time o Bladder sphincter constricts to stop urine flow

 SEMINAL VESICLES Saclike structures attaching to vas deferens at base of bladder Secretes fluid that helps regulate pH of semen Secretes fructose to provide energy to sperm Secretes prostaglandins which stimulate muscular contractions within female to aid in moving sperm towards egg.  PROSTATE GLAND Chestnut-shaped structure that secretes thin, milky fluid that neutralizes semen and acidic secretions in vagina Enhances motility of sperm cells If enlarged it will press on urethra limiting urine release and causing frequent urination sensation

 BULBOURETHRAL GLAND Secretes mucus like fluid in response to sexual stimulation Lubricates the end of penis in preparation for intercourse o But females produce most of lubricating fluid for intercourse  SEMEN Consists of sperm, secretions from seminal vesicle, prostate gland, and bulbourethral glands pH of 7.5 (slightly alkaline) 2 to 5 millimeters of semen released at one time containing about 120 million sperm per millimeter

 Production of sperm cells.06 mm long Acrosome : contains enzymes that help sperm penetrate egg Nucleus : in head, contains 23 chromosomes

 MEIOSIS 4 sperm cells for every spermatogonium

 ERECTION When male is stimulated, nerve impulses from spinal cord dilate arteries leading to penis Blood flow is reduced causing blood to accumulate in tissue resulting in a swelling and elongated penis  MALE SEX HORMONES (ANDROGENS) Male reproductive functions are controlled by hormones secreted by the hypothalamus, pituitary gland, and testes Testosterone: most important o Stimulates enlargement of gonads and accessory organs o Growth of hair o Larynx enlarge o Skin thickens o Growth of muscles o Bones thicken and strengthen o Increase RBC production