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MALE REPRODUCTIVE SYSTEM Reproductive ducts—ducts through which sperm pass after exiting testes until they exit from the body Epididymis—single, coiled tube about 6 m in length; lies along the top and behind the testis in the scrotum Sperm mature and develop the capacity for motility as they pass through epididymis Ductus (vas) deferens—receives sperm from the epididymis and transports them from scrotal sac through the abdominal cavity Passes through inguinal canal Joins duct of seminal vesicle to form the ejaculatory duct Slide 3

MALE REPRODUCTIVE SYSTEM Accessory, or supportive, sex glands—semen: mixture of sperm and secretions of accessory sex glands; averages 3 to 5 mL per ejaculation, with each milliliter containing about 100 million sperm Seminal vesicles Pouchlike glands that produce about 60% of seminal fluid volume Secretion is yellowish, thick, and rich in fructose to provide energy needed by sperm for motility Prostate gland Shaped like a doughnut and located below bladder Urethra passes through the gland Secretion represents 30% of seminal fluid volume—is thin and milk-colored Activates sperm and is needed for ongoing sperm motility Bulbourethral (Cowper’s) glands Resemble peas in size and shape Secrete mucus-like fluid constituting less than 5% of seminal fluid volume Slide 4

MALE REPRODUCTIVE SYSTEM External genitals Penis and scrotum called genitalia Penis has three columns of erectile tissue—two dorsal columns called corpora cavernosa and one ventral column surrounding urethra called corpus spongiosum Glans penis covered by foreskin (prepuce) Surgical removal of foreskin called circumcision Slide 5

FEMALE REPRODUCTIVE SYSTEM Structural plan—organs classified as essential or accessory Essential organs are gonads (ovaries), which produce sex cells (ova) Accessory organs of reproduction Ducts or modified ducts—including oviducts, uterus, and vagina Sex glands—including the breasts External genitals Slide 6

FEMALE REPRODUCTIVE SYSTEM Ovaries Structure and location Paired glands weighing about 3 g each Resemble large almonds Attached to ligaments in pelvic cavity on each side of uterus Microscopic structure (Figure 20-8) Ovarian follicles—contain an oocyte, which is an immature sex cell (about 1 million at birth) Primary follicles—about 400,000 at puberty are covered with granulosa cells About 350 to 500 mature follicles ovulate during the reproductive lifetime of most women—sometimes called graafian follicles Secondary follicles have a hollow chamber called the antrum Corpus luteum forms after ovulation Slide 7

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FEMALE REPRODUCTIVE SYSTEM Ovaries (cont.) Functions Oogenesis—this meiotic cell division produces daughter cells with equal chromosome numbers (23) but unequal cytoplasm; ovum is large; polar bodies are small and degenerate Production of estrogen and progesterone Granulosa cells surrounding the oocyte in the mature and growing follicles produce estrogen Corpus luteum produces progesterone Estrogen causes development and maintenance of secondary sex characteristics Progesterone stimulates secretory activity of uterine epithelium and assists estrogen in initiating menses Slide 9

FEMALE REPRODUCTIVE SYSTEM Reproductive ducts Uterine (fallopian) tubes (oviducts) Extend about 10 cm from uterus into abdominal cavity Expanded distal end surrounded by fimbriae Mucosal lining of tube is directly continuous with lining of abdominal cavity Uterus—composed of body, fundus, and cervix (Figure 20-9) Lies in pelvic cavity just behind urinary bladder Myometrium is muscle layer Endometrium lost in menstruation Menopause—end of repetitive menstrual cycles (about 45-50 years of age) Vagina Distensible tube about 10 cm long Located between urinary bladder and rectum in the pelvis Receives penis during sexual intercourse and is birth canal for normal delivery of baby at end of term of pregnancy Accessory or supportive sex glands Slide 10

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