The Male and Female Reproductive Systems

1. The Male and Female Reproductive Systems Katie Mackin, Alex Brockdorf, & Kayla Lovett IB Standards: 6.6.1 6.6.2 6.6.3 6.6.4 Nader Chapter (AP Standards): 41.1 (4.B.2) 41.3 (2.C.1, 4.B.2) 41.4 (3.D.4)

2. Male Reproductive System For IB need to label: Bladder Sperm duct Seminal vesicle Prostate gland Erectile tissue Penis Urethra Foreskin Scrotum Testis Note: In this diagram the “vas deferens” is referred to as the “ductus deferens

3. Journey of the Sperm • Testes: Produce sperm and sex hormone • Male gonads suspended in scrotum • Begin in abdominal cavity, descend to scrotum during puberty (if this does not happen and it left uncorrected the male suffers from sterility) • Sterility: Cooler than body temp. is required for development of sperm • **Testicular cancer is most common cancer in males 15-34 • Epididymis: Sites of maturation and some storage of the sperm • Tightly coiled tubules lying just outside testes • Maturation is required for sperm to swim to egg • Vas deferens: Conduct and store sperm • Propelled here after maturation for storage • Sexual arousal sends sperm to ejaculatory ducts then to the urethra

4. Journey of Sperm: Orgasm in Males • Penis: Organ of copopulation • Covered in foreskin until circumcision • During sexual arousal , nervous reflexes causes increased arterial blood flow to penis • Erection: This increased flow fills the blood space in erectile tissue and stiffens the normally flaccid penis to erect • Erectile dysfunction • Semen: (from Seminal vesicle, Prostate gland, Bulbourethral glands) • Fluid that contains nutrients, prostaglandins/ motility activators, slightly basic pH, seminalplasmin/ lubricating fluid • 2-5mL released on average: 60% seminal vesicle fluid, 30% prostatic fluids, <10% sperm

5. Penis Anatomy

6. Journey of Sperm: Orgasm in Males • Ejaculation • 1st Phase: Emission • Sperm enters ejaculatory duct • Glands release secretions, bulbourethral enter urethra first to cleanse it of urine residue • 2nd Phase: Expulsion • Contractions at base of penis expels semen from the opening of urethra • Release of myotonia (muscle tenseness) • Penis returns to flaccid state

7. Journey of Sperm

8. Sperm • Spermatogenesis takes place in seminiferous tubules • Need to release 50-150 million sperm per mL of semen • <100 sperm ever reach the egg, 1 penetrates

9. Hormone Regulation in Males • Hypothalmus control testes by hormone GnRH that stimulates anterior pituitary to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH) • FSH promotes spermatogenesis • LH control production of androgen testosterone in interstitial cells

10. 3 Roles of Testosterone • Causes male genitalia, such as penis, to develop in the fetus • Levels rise during puberty and causes secondary sexual characteristics Ex) pubic hair, enlarged penis, skeletal/ muscular growth • During adulthood, maintains sex drive *** Also one of the hormones needed to stimulate sperm production in testes

11. Female Reproductive System

12. Female Reproductive Organs • Ovaries: produce egg and sex hormone • Normally alternate by producing one oocyte a month • Oocyte = “egg” • Oviducts: conduct egg, location of fertilization • Extend from ovaries to uterus, • Not connected to ovary, instead have fimbriae that sweeps over ovaries • When oocyte bursts during ovulation it is swept into oviduct by fimbriae and cilia • If fertilized, the embryo is moved into uterus by cilia and muscle contraction

13. Female Reproductive Organs • Uterus: houses developing embryo and fetus • Narrow end is called cervix • The embryo completes its development embedded in the endometrium (uterine lining) • If the embryo is embedded elsewhere it is an “ectopic pregnancy • A small opening in the cervix leads to the vaginal canal • Vagina: receives penis during copopulation and serves as birth canal • A tube at a 45º angle to the small of the back • The mucosal lining is in fold and can distend (important during childbirth and intercourse) • It is acidic due to bacteria to protect itself from pathogenic bacteria (Recall: Semen is basic)

14. Female Reproductive Organs • Vulva: collective name for the female external genitalia • Clitoris is similar to male penis in being the main organ of female orgasm

15. Female Sex Hormones • Pituitary gland produces FSH and LH • FSH: stimulates the development of follicles (fluid filled sacs containing an egg cell) • LH: stimulates follicles to mature, release their egg (ovulation), and then develop into the corpus luteum • Ovary produces estrogen and progesterone • Development of secondary sexual characteristics • Stimulate the development of the uterus lining needed during pregnancy • Levels rise and fall according to menstrual cycle

16. The Female Breast • Contains 15-24 lobules, each with its own mammary duct • Duct begins at nipple and divides into more ducts ending with alveoli • Lactation: production of milk by cells of alveoli caused by prolactin • Milk contains water proteins, amino acids, sugars, and lysozymes (750 cal/ L) • Not produced during pregnancy because of feedback inhibition effect of estrogen and progesterone • Milk production begins a few days after delivery • Colostrum (rich in IgA) is produced in between

17. The Ovarian Cycle • Take place in the ovaries • Occurs as a follicle changes from primary to secondary to a vesicular follicle under the influence of FSH and LH from the anterior pituitary

18. Phases of Ovarian Cycle • Follicular phase (1st): FSH promotes the development of a follicle that primarily secretes estrogen • As estrogen rises in the blood it exerts negative feedback over the secretion of FSH, ending the follicular phase • When levels of estrogen become very high it exerts positive feedback on hypothalamus and anterior pituitary • The hypothalmuswill secrete a large amount of GhRH • This leads to a surge in LH and ovulation to be about the 14th day of a 28 day cycle • Ovulation • The vesicular follicle bursts, releasing the secondary oocyte (egg) surrounded by a clear membrane • Once a vesicular follicle has lost the secondary oocyte it becomes a corpus luteum • Luteal phase (2nd): LH promotes the development of the corpus luteum that primarily secretes progesterone • As the blood level of progesterone rises, it exerts negative feedback over LH production so the corpus luteum begins to degenerate • The remaining low levels of progesterone and estrogen begin the menstrual cycle

20. The Uterine Cycle • The 28 day cycle produced by estrogen and progesterone affecting the endometrium of the uterus • Day 1-5 (Menstruation): Low levels of female sex hormones causes endometrium to disintegrate and blood vessels to rupture • Day 6-13 (Proliferative): Increased estrogen production causes endometrium to thicken • Day 14 (Ovulation) • Day 15-28 (Secretory): Increase progesterone production by corpus luteum causes endometrium to double in thickness, producing a thick mucus signaling the lining can now receive an embryo • If not pregnant, the cycle restarts

22. Menstruation Facts • 7-10 days before menstruation some women suffer from PMS • During menstruation arteries that supply the endometrium constrict and capillaries weaken • Blood spillage detaches lining in random patches (not all) so mucus, blood, and degenerating endometrium descend from uterus through the vagina • Fibrinolysinkeeps blood from clotting • Lasts 3-5 days • Menarche, or first period, usually occurs between 11-13 • Amenorrhea: period does not occur by 16 or stops in women of reproductive age (pregnancy, menopause, birth control) • Menopause occurs when the ovaries cease functioning and menstruation ceases (age 45-55)

23. Behavorial Contraceptives: • Abstinence: not engaging in sexual intercourse • Rhythm method (Natural family planning): refraining from intercourse when conception is most likely • 10-20% pregnancy rate • Also method for achieving pregnancy • Option for religions that do not allow birth control • Coitus interruptus (Withdrawal): removal of the penis from the vagina before ejaculation • Unreliable method because of willpower and possibility the bulbourethral fluids contain sperm secreted before ejaculation

24. Permanent Mechanical Contraception • Vasectomy: Surgical severing of the vas deferentia that prevents sperm from entering the ejaculatory duct, instead phagocytized by macrophages • Tubal litigation: in which a woman’s oviducts are burned or clipped preventing sperm from reaching the oocyte • Nearly 100% effective

25. Mechanical Contraceptive • Male Condom (<10%): membrane sheath that fits over penis and collects semen. Only contraceptive to protect from STDs • Female Condom or Diaphragm • Both work best with spermicidal foam or jelly • Intrauterine Devices: Prevents fertilization or implantation

26. Chemical Contraception • The most commonly used birth control pills are a combination of a synthetic estrogen and a synthetic progestin (progesterone-like hormone). This combination acts by negative feed back to stop the release of GnRH by the hypothalamus and thus of FSH and LH by the pituitary. The prevention of LH release prevents ovulation. As a backup mechanism, the inhibition of FSH secretion by the low dose of estrogen in the pills prevents follicles from developing. • Minipill or Depo- Provera injection prevents fertilization mainly by causing thickening of a woman’s cervical mucus so that it blocks sperm from entering the uterus.

27. After Intercourse • Morning- after pill: Taken 72 hours after intercourse and is 85% effective. Most effective when the women was already using birth control • RU-486 is a pill currently being developed that blocks progesterone receptors in the uterus and can terminate a pregnancy non-surgically for 7 weeks • Abortion: termination of a pregnancy in progress • Each year about 1.5 million women in the U,S, choose abortions performed by physicians