Lecture 3 the reproductive systems
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Lecture 3 the reproductive systems

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Lecture 3 the reproductive systems

Lecture 3 the reproductive systems

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  • 1. Chapter 23 The Reproductive Systems Copyright 2010, John Wiley & Sons, Inc.
  • 2. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 3. Male Reproductive System Copyright 2010, John Wiley & Sons, Inc.
  • 4. Scrotum     Pouch that supports the testes Septum separates into separate sections for each testis Sperm requires temperatures 2-3°C below body temperature Allows raising and lowering testes to adjust temperature Copyright 2010, John Wiley & Sons, Inc.
  • 5. Testes   Paired oval glands Develop on embryo’s posterior wall and descend into scrotum    Starts in 7th month 200-300 lobules containing seminiferous tubules Lined with spermatogenic cells: spermatagonia & sertoli cells Copyright 2010, John Wiley & Sons, Inc.
  • 6. Testes Copyright 2010, John Wiley & Sons, Inc.
  • 7. Testes Copyright 2010, John Wiley & Sons, Inc.
  • 8. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 9. Meiosis  Cells have 23 pairs of chromosomes   Gametes are Haploid    Diploid = paired homologous chromosomes Unpaired chromosomes Meiosis is the process by which this can happen Required for gamete production Copyright 2010, John Wiley & Sons, Inc.
  • 10. Spermatogenesis Stages   Takes ~65–75 days from first division to release Spermatogonium divides: mitosis   One cell is stem cell other differentiates into primary (1o) 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 Copyright 2010, John Wiley & Sons, Inc.
  • 11. Spermatogenesis Stages  The cells from meiosis I are: secondary spermatocytes   Meiosis II: divide again   Each cell is haploid- has two copies of each chromatid One copy of each chromatid in each new cell Cells are: spermatids Copyright 2010, John Wiley & Sons, Inc.
  • 12. Spermatogenesis Stages   Spermiogenesis- each spermatid develops into a sperm cell Process requires support of Sertoli cell  Often called “nurse cell” Copyright 2010, John Wiley & Sons, Inc.
  • 13. Spermatogenesis Copyright 2010, John Wiley & Sons, Inc.
  • 14. Spermatozoa Structure  ~300 million /day       Life time ~ 48 hrs in female tract Structure: Head, middle, tail Tail- flagellum = motility Middle: mitochondria = energy Head-chromosomes + acrosomal cap Acrosome-enzymes-  penetrating egg Copyright 2010, John Wiley & Sons, Inc.
  • 15. Spermatozoa Structure Copyright 2010, John Wiley & Sons, Inc.
  • 16. Hormonal Control       At puberty- hypothalamus  GnRH  Pituitary LH & FSH LH Leydig cells  testosterone  Negative feedback to suppress LH & GnRH FSH + testosterone stimulate spermatogenesis Sertoli cells  inhibin  inhibits FSH release  optimum sperm production Copyright 2010, John Wiley & Sons, Inc.
  • 17. Hormonal Control Copyright 2010, John Wiley & Sons, Inc.
  • 18. Androgen Effects  Prenatal: male pattern of development:   Puberty: enlargement of organs, secondary characteristics    Male ducts, descent of testes, external genitals and brain regions Muscular and skeletal growth, hair patterns, thickening of skin Sexual function: sexual behavior, spermatogenesis and libido Stimulation of anabolism: stimulate protein synthesis and muscle and bone growth Copyright 2010, John Wiley & Sons, Inc.
  • 19. Ducts: Sperm Route      Epdidymis vas (ductus) deferens  ejaculatory duct (by seminal vesicles)  urethra in prostate Pass bulbourethral glands (alkaline + mucus fluid)  penis and ejaculation Copyright 2010, John Wiley & Sons, Inc.
  • 20. Accessory Glands  Seminal vesicles: seminal fluid     Prostate: surrounds upper urethra   Fructose (sperm ATP production + alkalinity (neutralize acid in tracts) + prostaglandins-activation of sperm Increases volume + adds antibiotics Bulbourethral glands  More alkalinity + mucus fluid Copyright 2010, John Wiley & Sons, Inc.
  • 21. Penis  Contains urethra- root, body & glans penis    Root: attached portion Body: 3 cylindrical masses erectile     Passage for semen and urine Dorsal: Corpora Cavernosa Penis Midventral: Corpus Spongiosum penis- contains urethra Glans penis has external urethral oriface Uncircumcised glans covered by prepuce Copyright 2010, John Wiley & Sons, Inc.
  • 22. Arousal & Ejaculation  Parasympathetic impulses erection    Dilation of penile arteries Volume compresses veins so outflow is slowed Ejaculation is a Sympathetic reflex    Peristaltic contractions in ductus deferens, seminal vesicles, ejaculatory ducts & prostate emission Sphincter at urinary bladder closes Forceful release of semen from urethra Copyright 2010, John Wiley & Sons, Inc.
  • 23. 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 or pudendum) Copyright 2010, John Wiley & Sons, Inc.
  • 24. Female Reproductive System Copyright 2010, John Wiley & Sons, Inc.
  • 25. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 26. Histological Structure Copyright 2010, John Wiley & Sons, Inc.
  • 27. Oogenesis  Begins before birth   Meiosis I- start before birth & finish at puberty     Oocytes not continually produced 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) Copyright 2010, John Wiley & Sons, Inc.
  • 28. 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 + 2nd polar body Nuclei of sperm & ovum unite Diploid zygote Copyright 2010, John Wiley & Sons, Inc.
  • 29. Oogenesis Copyright 2010, John Wiley & Sons, Inc.
  • 30. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 31. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 32. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 33. Uterus and Vagina Copyright 2010, John Wiley & Sons, Inc.
  • 34. Perineum and Vulva     Perineum: Diamond-shaped area between thigh & buttocks of both males & females Vulva or pudendum = external genitalia Mons pubis- elevation of adipose tissue Labia majora- extends back from mons pubis   Same fetal tissue as scrotum Labia minora- internal to majora Copyright 2010, John Wiley & Sons, Inc.
  • 35. Perineum and Vulva  Clitoris: small cylindrical mass of erectile tissue & nerves     Vestibule: between labia minora External urethral oriface: anterior to vaginal oriface Paraurethral glands: either side of urethra    Also contains prepuce & glans Same embryonic tissue as prostate Secretes mucus Greater vestibular glands- adds to mucus  Comparable to bulbourethral glands Copyright 2010, John Wiley & Sons, Inc.
  • 36. Perineum and Vulva Copyright 2010, John Wiley & Sons, Inc.
  • 37. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 38. Mammary Glands Copyright 2010, John Wiley & Sons, Inc.
  • 39. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 40. Female Reproductive Cycle Copyright 2010, John Wiley & Sons, Inc.
  • 41. Female Reproductive Cycle Copyright 2010, John Wiley & Sons, Inc.
  • 42. Hormonal Regulation       GnRH (hypothalamus) controls GnRH FSH & LH FSH follicle growth & estrogen secretion High estrogen  LH surge  ovulation LH supports corpus luteum  progesterone & estrogen secretion + relaxin & inhibin Inhibin  decreased FSH release Copyright 2010, John Wiley & Sons, Inc.
  • 43. 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 Copyright 2010, John Wiley & Sons, Inc.
  • 44. Phases of Cycle  Menstrual phase: ~1st 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 Copyright 2010, John Wiley & Sons, Inc.
  • 45. Phases of Cycle  Ovulation   Release of 2o oocyte with LH surge Postovulatory   Ovaries: follicle collapses corpus luteum (luteal phase) If no fertilization  FSH & LH  corpus albicans & decreased Progesterone  menstruation Copyright 2010, John Wiley & Sons, Inc.
  • 46. Phases of Cycle   If fertilization & division human chorionic gonadotrophin (hCG) stimulates corpus luteum secretion Uterus: Progesterone & estrogens complete development of uterus for implantation Copyright 2010, John Wiley & Sons, Inc.
  • 47. Summary of Hormonal Interactions Copyright 2010, John Wiley & Sons, Inc.
  • 48. Birth Control Methods  Surgical: vasectomy in males   Tubal ligation in females   IUD, condoms, cervical cap Timing   Oral hormones, implants, injections, spermicide Blocking physically   Close uterine tubes Chemical interference   Ductus deferens segment removed Temperature, mucus charting, calendar Abortion Copyright 2010, John Wiley & Sons, Inc.
  • 49. Aging   Puberty- pulses of LH & FSH Rise in sex steroids    Follicles become exhausted menopause     Growth & secondary characteristics Start of female reproductive cycle Estrogen secretion declines Lose feedback on pituitary  high FSH & LH Decline in estrogen supported functions In males: slower decline of function Copyright 2010, John Wiley & Sons, Inc.
  • 50. End of Chapter 23  Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein. Copyright 2010, John Wiley & Sons, Inc.