1. CHAPTER 14 The Reproductive System
BIOLOGY OF HUMAN AGING
CHAPTER 14
The Reproductive System

2. 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)

3. Side View of Male Reproductive System

4. Front View of Male Reproductive System

5. 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

6. Spermatogenesis Occurs in Seminiferous Tubules of Testes

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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

14. 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.

15. Frontal View of Female Reproductive System

16. Side View of Female Reproductive System

17. 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.

18. Oogenesis and Ovary Structure

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

20. Fertilization Occurs in the Oviducts

21. 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.

22. Vagina: Thin walled, muscular chamber.
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.

23. Stages of Female Reproductive Cycle

24. Age-related changes 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

25. Age-related changes 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

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