BIOLOGY OF HUMAN AGING

1. BIOLOGY OF HUMAN AGING CHAPTER 14 The Reproductive System

2. Reproductive System of Humans Reproductive Functions of Female: • Produces eggs (ova) • Receives sperm • Incubates and nourishes the embryo and fetus • Gives birth All of these processes are regulated and coordinated by hormones secreted by: • Hypothalamus • Pituitary gland • Ovaries

3. Reproductive System of Humans Major Organs of Female Reproductive System: • Ovaries: Produce ova and sex hormones. • Follicles: A single egg with surrounding cells that nourish and protect it.

4. Frontal View of Female Reproductive System

5. Side View of Female Reproductive System

6. Female Reproductive System: • Ovulation & Oogenesis: After puberty, each month one immature egg (oocyte), is released from ovary. • Pituitary hormone FSH (follicle stimulating hormone) causes a follicle to enlarge. • Another pituitary hormone LH (luteinizing hormone) causes the secondary oocyte to be released by the ovary during ovulation.

7. Oogenesis and Ovary Structure

8. Major Organs of Female Reproductive System: • Oviducts (Fallopian Tubes): Transport the egg from the ovary to the uterus. • Fertilization

9. Fertilization Occurs in the Oviducts

10. Reproductive System of Humans Major Organs of Female Reproductive System: • Uterus: Incubates the embryo/fetus. • Endometrium: Inner mucous lining, which thickens each month in preparation for pregnancy. • If fertilization does not occur, endometrium breaks down and is discharged during menstruation. • If fertilization occurs, the egg implants in the endometrium which supports its growth until the placenta develops.

11. Reproductive System of Humans Major Organs of Female Reproductive System: • Cervix: Lower portion of the uterus, which projects into the vagina. • Vagina: Thin walled, muscular chamber. • Receives the sperm and penis • Acid pH kills bacteria and sperm cells • External structures: • Clitoris: Equivalent to male penis. • Labia minora: Skin folds that border vaginal opening. • Labia majora: Protect entire genital region.

12. Stages of Female Reproductive Cycle

13. Reproductive System of Humans Reproductive Functions of Male: • Produces sperm • Delivers sperm to female reproductive tract All of these processes are regulated and coordinated by hormones secreted by: • Hypothalamus • Pituitary gland • Testes (Sing. Testis)

14. Side View of Male Reproductive System

15. Front View of Male Reproductive System

16. Major Organs of Male Reproductive System: • Testes: Paired male gonads. • Produce sperm through spermatogenesis, which produces four sperm cells of equal size. • Spermatogenesis occurs in a vast system of hollow tubes called seminiferous tubules. • Sperm

17. Spermatogenesis Occurs in Seminiferous Tubules of Testes

18. Reproductive System of Humans Major Organs of Male Reproductive System: • Epididymus: • Large coiled tube that surrounds testes. • Stores sperm while they develop fertilizing ability and motility (about 20 days). • Vas Deferens: • Long muscular ducts from scrotum to back of bladder. • During ejaculation, the sperm pass from epididymus into these two ducts.

19. Reproductive System of Humans Major Organs of Male Reproductive System: • Ejaculatory Duct: • Short duct after two vas deferens ducts unite. • Urethra: • Deliver sperm to the exterior. • In males, urine and sperm pass through the urethra.

20. Reproductive System of Humans Major Organs of Male Reproductive System: Accessory Glands: • Seminal vesicles (2): Secrete fluid that nourishes sperm. • Thick, clear, alkaline fluid. • Contains: • Fructose: Provides energy for sperm motility. • Sperm cells become highly motile when mixed with this fluid.

21. Accessory Glands: Produce semen. • Prostate gland: Produces a thin milky secretion. • Largest of semen secreting glands. • Produces an antibiotic that may prevent urinary tract infections in men.

22. Major Organs of Male Reproductive System: Accesory Glands: Produce semen. • Bulbourethral glands (2): Release a mucous secretion that lubricates penis and facilitates its entry into vagina.

23. Major Organs of Male Reproductive System: • Penis: organ that delivers sperm to female body. • Composed of three cylinders of erectile tissue. • During sexual arousal, the penis fills with blood from the arteries. • Erection is essential for penetration. • Impotence is the inability to maintain an erection. • May be caused by alcohol, drugs, illness, and/or emotional problems. • Viagra acts by relaxing smooth muscle of penis blood vessels, allowing blood to enter erectile tissue.

24. Changes in Men • Decrease in size and firmness of testes with aging • Decline in the secretion of testosterone • Decline in number of sperm cells • Degeneration of some seminiferous tubules • Fibrous connective tissue formation increases between the tubules diminish blood supply  atrophy • Semen volume reduced with aging • Prostate gland often enlarge with aging • Seminal vesicles decrease in weight and storage capacity • A decrease in secretory activities of Bulbourethral glands • Atrophy of penis  loss of elasticity problem in erection Age-related changes

25. Changes in Women • Reduced amounts of estrogens and progesterone being secreted • Cessation of the menstrual cycle signal beginning of menopause • Changes in follicle cells in the ovaries unable to respond to FSH and LH • Symptoms associated with onset of menopause: • Hot flashes, sweating, and red patches as a result of irregular dilation and constriction of blood vessels. • Atrophy of ovaries and increase formation of fibrosis. • Degeneration of follicles (follicular cysts) • Reproductive organs tend to decrease in size • Uterine tubes become thin and undergo weaker peristaltic contraction. Also more infections. • The vagina becomes narrower and shorter. • Loss of elasticity and dryness of vagina due to less secretion of glands associated with female reproductive organs. Hormonal and other observable changes Age-related changes

26. Cancer • Atrophic Vaginitis • Prolapse of the Uterus • Impotence • Diminish Sexual Functioning Age-related Dysfunctions