1. Copyright 2010, John Wiley & Sons, Inc. Chapter 23 The Reproductive Systems

2. Male vs. Female FeatureFemaleMale Essential organsovariesTestes Sex CellsOva (egg)Sperm Main hormonesEstrogen/progesteronetestoterone Duct SystemUterine tubes / uterus / vagina Epididymus / vas deferens / urethra Copyright 2010, John Wiley & Sons, Inc.

3. Male Reproductive System Organs: testes, ducts, glands & supporting structures Ducts: epdidymis, ductus deferens, ejaculatory ducts & urethra Glands: seminal vesicles, prostate, bulbourethral glands Supporting structures include scrotum & penis

4. Copyright 2010, John Wiley & Sons, Inc. Scrotum Pouch that supports the testes Septum separates into separate sections for each testis Sperm requires temperatures 2-3 ° C below body temperature to develop, so that is why they hang away from the body Allows raising and lowering testes to adjust temperature

5. Copyright 2010, John Wiley & Sons, Inc. Testes Paired oval glands Develop on embryo’s posterior wall and descend into scrotum  Starts in 7 th month 200-300 lobules containing seminiferous tubules Lined with spermatogenic cells: spermatagonia & sertoli cells

6. Copyright 2010, John Wiley & Sons, Inc. Spermatogenesis Stages: meiosis I, meiosis II, spermiogenesis Occurs in seminiferous tubules Cell types involved: spermatagonia, sertoli cells & interstitial cells (leydig cells) Move through rete testes  epididymis

7. Copyright 2010, John Wiley & Sons, Inc. Meiosis Cells have 23 pairs of chromosomes  Diploid = paired homologous chromosomes Gametes are Haploid  Unpaired chromosomes Meiosis is the process by which this can happen Required for gamete production

8. Copyright 2010, John Wiley & Sons, Inc. Spermatogenesis

9. Copyright 2010, John Wiley & Sons, Inc. Spermatogenesis Stages Takes ~65–75 days from first division to release Spermatogonium divides: mitosis  One cell is stem cell other differentiates into primary (1 o ) spermatocyte Meiosis I: chromosomes replicate  Line up as pairs of homologous chromosomes  Chromosomes twist and some exchange of material between chromosomes can occur  Each homologous pair separates and a member moves to opposite end of cell   After cell division each cell is haploid

10. Copyright 2010, John Wiley & Sons, Inc. Spermatogenesis Stages The cells from meiosis I are: secondary spermatocytes  Each cell is haploid- has two copies of each chromatid Meiosis II: divide again  One copy of each chromatid in each new cell Cells are: spermatids

11. Copyright 2010, John Wiley & Sons, Inc. Spermatogenesis Stages Spermiogenesis- each spermatid develops into a sperm cell Process requires support of Sertoli cell  Often called “nurse cell”

12. Copyright 2010, John Wiley & Sons, Inc. Spermatozoa Structure ~300 million /day  Life time of sperm ~ 48 hrs in female tract Structure: Head, middle, tail  Tail- flagellum = motility  Middle: mitochondria = energy  Head-chromosomes + acrosomal cap  Acrosome-enzymes  penetrating egg

13. Copyright 2010, John Wiley & Sons, Inc. Spermatozoa Structure

14. Copyright 2010, John Wiley & Sons, Inc. Hormonal Control At puberty- hypothalamus  GnRH (gonadotropin releasing hormone)  Pituitary  LH (leutinizing hormone) & FSH (follicle stimulating hormone) LH  Leydig cells  testosterone  Negative feedback to suppress LH & GnRH FSH + testosterone stimulate spermatogenesis Sertoli cells  inhibin  inhibits FSH release  optimum sperm production

15. Copyright 2010, John Wiley & Sons, Inc. Androgen Effects Prenatal: male pattern of development:  Male ducts, descent of testes, external genitals and brain regions Puberty: enlargement of organs, secondary characteristics  Muscular and skeletal growth, hair patterns, thickening of skin Sexual function: sexual behavior, spermatogenesis and libido Stimulation of protein building: stimulate protein synthesis and muscle and bone growth

16. Copyright 2010, John Wiley & Sons, Inc. Ducts: Sperm Route Epdidymis  vas (ductus) deferens  ejaculatory duct (by seminal vesicles)  urethra in prostate Pass bulbourethral glands (alkaline + mucus fluid)  penis and ejaculation

17. Copyright 2010, John Wiley & Sons, Inc. Accessory Glands Seminal vesicles: seminal fluid  Fructose (sperm ATP production  + alkalinity (neutralize acid in tracts)  + prostaglandins-activation of sperm Prostate: surrounds upper urethra  Increases volume + adds antibiotics Bulbourethral glands  More alkalinity + mucus fluid

18. Copyright 2010, John Wiley & Sons, Inc. Female Reproductive System Ovaries: paired organs- produce  Secondary oocytes  ova (after fertilization)  Hormones: progesterone & estrogens  From same embryonic tissue as testes Uterine (fallopian) tubes & uterus Vagina External organs (vulva)

19. Copyright 2010, John Wiley & Sons, Inc. Histological Structure Germinal epithelium: covers surface Ovarian cortex: connective tissue containing follicles Follicle; oocyte + surrounding cells  Surrounding cells nourish oocyte & produce hormones  Grows during maturation  Graafian follicle  ovulation Post ovulation  corpus luteum   Progesterone, relaxin & inhibin

20. Copyright 2010, John Wiley & Sons, Inc. Oogenesis Begins before birth  Oocytes not continually produced Meiosis I- start before birth & finish at puberty  During fetal development  form oogonia  Before birth some  primary oocytes  Monthly hormones  some to complete meiosis I Two uneven haploid cells = secondary oocyte & polar body (discarded)

21. Copyright 2010, John Wiley & Sons, Inc. Oogenesis Secondary oocyte has most of cytosol Then begins meiosis 2 & stops Then ovulation  into uterine tube If fertilization then meiosis II is completed  ovum + 2 nd polar body Nuclei of sperm & ovum unite  Diploid zygote

22. Copyright 2010, John Wiley & Sons, Inc. Oogenesis

23. Copyright 2010, John Wiley & Sons, Inc. Uterine Tubes Two tubes- extend laterally from uterus End in fringe  fimbriae Fimbriae sweep secondary oocyte into tube Oocyte moved by cilia lining wall Zygote reaches uterus in ~7 days

24. Copyright 2010, John Wiley & Sons, Inc. Uterus Pathway for sperm & site of implantation Fundus: dome-shaped area above tubes= Body: tapering central portion Cervix: narrow opening into vagina Uterine cavity: interior of body

25. Copyright 2010, John Wiley & Sons, Inc. Vagina Extends from exterior to cervix Receptacles for penis and outlet for menstrual flow Fornix- recess surrounds cervix Acid environment- prevents bacterial growth Smooth muscular layer- adjusts for intercourse or birth Thin membrane fold can cover vaginal orifice = hymen

26. Copyright 2010, John Wiley & Sons, Inc. Mammary Glands Modified suduriferous glands Nipple: pigmented projection with openings Areola: surrounds nipple Internally:15-20 lobes  lobules  alveoli = milk secreting glands  Matures at puberty Lactation = synthesis, secretion & ejection of milk

27. Copyright 2010, John Wiley & Sons, Inc. Mammary Glands

28. Copyright 2010, John Wiley & Sons, Inc. Female Reproductive Cycle 24-34 days- cycles in both ovaries & uterus Ovarian cycle = maturation of follicle, ovulation & corpus luteum formation Uterine Cycle = menstrual cycle  Controlled by hormones from ovary  Estrogens  growth of endometrium Progesterone supports endometrium for implantation Combine cycles = reproductive cycle

29. Copyright 2010, John Wiley & Sons, Inc. Female Reproductive Cycle

30. Copyright 2010, John Wiley & Sons, Inc. Female Reproductive Cycle

31. Copyright 2010, John Wiley & Sons, Inc. Hormones Estrogen development & maintenance of reproductive structures & secondary characteristics   protein synthesis & growth  Lower blood cholesterol level Progesterone maintains myometrium for implantation Relaxin: relaxes uterus- inhibits myometrium Inhibin: inhibits FSH release

32. Copyright 2010, John Wiley & Sons, Inc. Phases of Cycle Menstrual phase: ~1 st 5 days of cycle  Several Ovarian follicles enlarge  Decreased progesterone & estrogen  uterine arteries constrict  endometrium sloughs off Preovulatory: between menstruation & ovulation  Ovaries: follicles grow & secrete estrogen & inhibin  one dominates  Uterus: growth of new endometrium

33. Copyright 2010, John Wiley & Sons, Inc. Phases of Cycle Ovulation  Release of 2 o oocyte with LH surge Postovulatory  Ovaries: follicle collapses  corpus luteum (luteal phase)  If no fertilization   FSH & LH  corpus albicans & decreased Progesterone  menstruation

34. Copyright 2010, John Wiley & Sons, Inc. Phases of Cycle If fertilization & division  human chorionic gonadotrophin (hCG)  stimulates corpus luteum  secretion Uterus: Progesterone & estrogens  complete development of uterus for implantation

35. Copyright 2010, John Wiley & Sons, Inc. Birth Control Methods Surgical: vasectomy in males  Ductus deferens segment removed Tubal ligation in females  Close uterine tubes Chemical interference  Oral hormones, implants, injections, spermicide Blocking physically  IUD, condoms, cervical cap Timing  Temperature, mucus charting, calendar Abortion

36. Copyright 2010, John Wiley & Sons, Inc. Aging Puberty- pulses of LH & FSH  Rise in sex steroids   Growth & secondary characteristics  Start of female reproductive cycle Follicles become exhausted  menopause  Estrogen secretion declines   Lose feedback on pituitary  high FSH & LH   Decline in estrogen supported functions In males: slower decline of function