Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26The Reproductive SystemThe Reproductive System• Function:Perpetuation of an individual’s genetic materialNot essential for survival• Asexual Reproduction:Offspring’s genes come from only one parent; offspring and parents are genetically identical• Sexual Reproduction:Offspring’s genes come from two parents; offspring are unique from parents- External or internal fertilizationThe Reproductive System• Sex differences in reproduction:Males: Produce many small, “cheap” gametes (sperm) Acyclic reproductive functionFemales: Produce fewer large, “expensive” gametes (ova)Cyclic reproductive functionMany small sperm on one large eggThe Male Reproductive System• Testes– Produce sperm, sex steroids– Housed in scrotum•Epididymis– Stores sperm while it matures•Vas Deferens– Transports sperm to ejaculatory duct•Seminal Vesicles, Prostate Gland, Bulbourethral Glands– Make other components of semen•Penis– Made of erectile tissue that fills with blood– Discharges semen via urethraThe Male Reproductive SystemHormonal Control of Testes1. Hypothalamus secretes releasing hormone2. Releasing hormone  Follicle Stim. Hormone (FSH) and Luteinizing Hormone (LH)3. FSH  Sperm Production LH  Testosterone  Sperm Production4. Testosterone inhibits releasing hormone and LH- negative feedback1.2.3.4.SpermatogenesisSperm cells start development in seminiferous tubulesStart off as diploid (2 copies of each chromosome), end up haploid (1 copy)Sperm travel to epididymis where they mature, become motile, and are storedThe Female Reproductive System• Oviducts (Fallopian tubes)– Site of fertilization• Ovaries– Produce ova, sex steroids• Uterus (womb)– Holds developing embryo/fetus– Endometrium = inner lining (implantation)• Cervix– “Neck” of uterus• Vagina– Birth canal– Copulation; receives spermThe Female Reproductive SystemFollicleEgg cell (ova) + surrounding cell layers– nourish & protect ovum– secrete sex steroidsThe Female Reproductive CycleCyclical changes in:• Hormone secretion– Hypothalamus, anterior pituitary, ovaries• Uterus– Proliferation of endometrium– Breakdown of endometrium (menstruation)• Ovary– Growth of follicles– Release of egg cell (ovum) from one follicle (ovulation)The Female Reproductive CycleThe Female Reproductive CycleThe Female Reproductive CycleCorpus luteum degenerates if no fertilizationBaby Animal Break!The Female Reproductive CycleThe Female Reproductive CycleHypothalamus / Anterior PituitaryFollicle Stim. Hormone / Luteinizing HormoneFollicle (ovum and corpus luteum)Estrogen and ProgesteroneEndometriumThe Female Reproductive Cycle– FSH stimulates follicular development – Developing follicles secrete estrogen (E)– E exerts initially exerts negative feedback on LH and FSH; possibly to prevent 2nd ovulation– E induces growth of endometriumPre-ovulation Phase:The Female Reproductive Cycle– Rising E levels exert positive feedback on LH and FSH– LH surge triggers ovulationOvulation:The Female Reproductive Cycle– Corpus luteum forms and secretes Progesterone & Estrogen inhibit LH & FSHP maintains endometrium– CL degenerates after 14 days if no fertilization– Progesterone & Estrogen dropPost-ovulation Phase:The Female Reproductive Cycle– Endometrium is shed (menstruation)– Removal of negative feedback allows LH and FSH to rise– A new set of follicles develops (new cycle begins)Post-ovulation Phase:BirthHow Does Chemical Contraception Work?– Contains synthetic E and P (minipill - P only)– Negative feedback suppresses LH and FSH– Blocks follicle development and ovulation– Causes cervical mucus to be “hostile” to sperm The Birth Control Pill– High doses of synthetic E and/or P– Blocks ovulation– Alters endometrium to prevent implantationThe Morning-After Pill (up to ~72 h)– Blocks P receptors– Causes breakdown of endometriumRU 486 (The “Abortion Pill”) (first 9 weeks of pregnancy)Fertility• Maximum fertility:– ~ 5 days before through 1-2 day after ovulation• Calculating the timing of ovulation:– Ovulation to menstruation usually 14 days– Menstruation to ovulation more variable– So, timing of maximum fertility can be determined retroactively but not proactivelyFertilitySexually Transmitted DiseasesAbstinence and latex condoms are the most effective at preventing the spread of