Survey of Anatomy and Physiology chapter 17


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Survey of Anatomy and Physiology chapter 17

  1. 1. 17 The Reproductive System: Replacement and Repair
  2. 2. Reproduction: Mitosis vs. Meiosis  Cells and tissues get damaged or simply wear out  Damaged or worn-out cells and tissues must be repaired or replaced  Asexual reproduction, or mitosis, is the process by which cells make exact copies of themselves, and is essential to maintain a healthy body
  3. 3. Meiosis to Carry On the Species  Ultimately, cellular reproduction needed for complicated process by which humans produce new humans: sexual reproduction  Without this ability, the human species would die out and journey for human race would end
  4. 4. Reproduction: Mitosis vs. Meiosis  Cellular reproduction: process of making new cell  Asexual reproduction: cells make identical copies of themselves without involvement of another cell  Most cells can reproduce themselves asexually, whether animal cells, plant cells, or bacteria
  5. 5. Reproduction: Mitosis vs. Meiosis  Includes how cell is to function within body and blueprints for reproduction  All chromosomes must be copied before cell can divide  Mitosis is only way eukaryotic cells can reproduce asexually  Any time cells must be replaced, mitosis is method used to replace them
  6. 6. Reproduction: Mitosis vs. Meiosis  Without mitosis, body would not be able to grow or replace old or damaged cells  Chief difference: meiosis pairs homologous (similar in size, shape and genetic content)one from each human
  7. 7. Meiosis to Carry On the Species  Sexual reproduction: to perpetuate species  Union of cell from one organism with cell from another organism of same species
  8. 8. Gametes- Sperm and Egg  In animals, females produce eggs (ova), males produce sperm, and special cells called gametes  Gametes produced by meiosis (reduction division) because daughter cells produced at end of meiosis have half as many chromosomes as original mother cell
  9. 9. Meiosis to Carry on the Species  Daughter cells must have half as many chromosomes because they will fuse together during sexual reproduction  In humans, total number is 46 chromosomes; there are 23 pairs of chromosomes  Each pair of chromosomes consists of one chromosome from your father and one from your mother
  10. 10. 23rd Chromosome-Determines Sex of the Child  23rd “pair” is sex chromosome, so named because they determine sex of baby  XX is female, XY is male; father determines sex of baby because mother can only contribute X chromosomes
  11. 11. The Human Life Cycle-Egg and Sperm  Eggs and sperm, with only half as many chromosomes as other cells, are produced by meiosis in specialized organs known as gonads  Testes (male); ovaries (female)
  12. 12. The Human Life Cycle  During sexual reproduction, gametes unite and combine their genetic material; union is called fertilization  Fertilized egg (zygote) has 46 chromosomes  Zygote reproduces millions of times via mitosis and develops within female to change from embryo to fetus
  13. 13. Human Reproductive System First cell division of the zygote on its way to becoming a human
  14. 14. Human Reproductive System Reproductive organs called genitalia and are divided into: Primary genitalia: gonads that produce gametes Secondary genitalia: other structures that aid in reproductive process
  15. 15. Human Reproductive System o Primary genitalia are ovaries o Secondary genitalia are Fallopian tubes, uterus, vagina, external genitalia called vulva o Ovaries are paired structures, about 3 cm long, in peritoneal cavity, with one ovary on either side of uterus
  16. 16. Figure 17-3 Internal female reproductive organs o Ovaries covered by fibrous capsule called tunica albuginea. Interior has cortex, which contains eggs o Uterine tubes (oviducts or Fallopian tubes) are passageways for eggs to get to uterus
  17. 17. Figure 17-3 (continued) Internal female reproductive organs
  18. 18. The Uterus  Thick-walled and pear-shaped; found in pelvic cavity posterior and superior to urinary bladder and anterior to rectum
  19. 19. The Uterus  Consists of three layers:  Perimetrium: outermost layer, visceral peritoneum  Myometrium: consists of smooth muscle  Endometrium: inner lining is mucosa layer of columnar epithelium and secretory cells with two divisions Basal layer: responsible for regenerating uterine lining each month Functional layer: sheds about every 28 days when woman has her period
  20. 20. The Vagina  Smooth muscle tube with mucous membrane lining; 10 cm long, running from uterus to outside of body  Purpose is to receive penis during intercourse and allow for passage of menstrual fluid out of uterus  Also called birth canal, since another function is to allow movement of baby out of uterus during childbirth
  21. 21. The Vagina  External opening may be covered by a perforated membrane (hymen)  Torn hymen once thought to “prove” that woman had intercourse  Many hymens are highly perforated and easily ruptured by day-today activities such as riding a bike or jogging
  22. 22. The Cervical Canal and Cervix  Cervix is valve like portion of uterus that protrudes into vagina, while cervical canal connects with vagina
  23. 23. Screening for Cervical Cancer  A PAP smear is done during a pelvic exam that involves scraping cervical cells, checking for cancer  Cervical cancer is now known to be a sexually transmitted disease caused by specific strains of HPV (human papilloma virus)
  24. 24. Figure 17-5 The external female genitalia o Collectively known as vulva; complex and important part of reproduction o Vulva surrounded by two prominences called labia majora; rounded fat deposits that surround entrance to vagina o Labia majora meet anteriorly to form mons pubis, covered by pubic hair
  25. 25. Figure 17-6 The mammary glands. o Another set of external accessory sexual organs in female; milk production glands housed in breasts o In young children, mammary tissue virtually identical in boys and girls o At puberty, estrogen and progesterone stimulate breast development in girls
  26. 26. The Menstrual Cycle
  27. 27. The Menstrual Cycle  Takes approximately 28 days; involves ovaries, uterus, pituitary gland, and hypothalamus  Ovarian cycle involves monthly maturation and release of eggs from ovary  Uterine cycle consists of monthly buildup, decaying, and shedding of uterine lining
  28. 28. The Menstrual Cycle  Cycles begin in woman’s teen years, during puberty with menarche; end during her 40s or 50s in menopause  Goal is to release egg for fertilization and prepare uterus to receive and nourish fertilized egg should pregnancy result  If pregnancy does not result, uterine lining will shed and cycle will begin again
  29. 29. The Menstrual Cycle  Begins with first day of menses; time period when uterine lining is shed  Menstruation: term referring to actual shedding of endometrium
  30. 30. The Menstrual Cycle  Menses can last 4 to 5 days; can be longer or shorter in different women; can vary month to month in same woman
  31. 31. The Menstrual Cycle  The smooth muscle layer of the uterus responsible for muscular contractions with childbirth and the cramping that occurs with menstruation
  32. 32. The Follicular Phase & Luteal Phase  From day 1–14 oocyte (egg cell) undergoing number of developmental changes getting ready for ovulation on day 14 with increase in ESTROGEN  Ovulation: release of mature egg from ovary followed by the increase of PROGESTERONE on days 15-28 or second half of the cycle
  33. 33. Menstrual Cycle  If oocyte fertilized by sperm, it will implant in thickened endometrium  If egg doesn’t implant within few days, endometrium will begin to decay and menstruation will occur within two weeks
  34. 34. Hormonal Control-Ovarian & Pituitary  FOUR HORMONES control menstrual cycle:  Ovarian hormones: estrogen and progesterone  Pituitary hormones luteinizing hormone (LH) and follicle-stimulation hormone (FSH)
  35. 35. Menstrual Cycle  It is the CORPUS LUTEUM (what remains of the ruptured follicle after ovulation) that secretes progesterone to maintain the endometrial lining of the uterus to support the fertilized egg
  36. 36. Menstrual Cycle  Decreasing progesterone cause degeneration of endometrium, followed by menstruation  Decreased progesterone also releases hypothalamus and pituitary from inhibition  FSH and LH levels rise and cycle begins again
  37. 37. Menstrual Cycle  EXTRA CREDIT Essay on the Final Exam will have questions on the ovarian hormones involved in menstrual cycle, the pituitary hormones involved and the timing of the menstruation as well as the hormone measured in pregnancy test  TO PREPARE: Watch the video on “Ovulation and the Menstrual Cycle” and use your book, Page 494
  38. 38. Menstrual Cycle  Premenstrual Syndrome is characterized by predictable cognitive, physical, emotional and behavioral symptoms associated with the luteal phase (approximately 5 days before menses)  No screening test to detect  Treatment depends on severity
  39. 39. Menstrual Cycle  Increased stress and/or illness can affect the onset or frequency of menstrual cycle due to it’s affect on the hypothalamus — an area of the brain that controls the hormones that regulate the menstrual cycle.  Ovulation and menstruation may stop as a result.
  40. 40. Pregnancy and HCG Levels  If pregnancy does result, implanted fertilized egg secretes hormone called human chorionic gonadotropin (HCG)  HCG stimulates corpus luteum to keep secreting progesterone and a little estrogen to maintain the uterine lining
  41. 41. Pregnancy and HCG Levels  This is the hormone that is measured in the blood or urine when a pregnancy test is done
  42. 42. Table 17-1 Pregnancy Hormones Controlling
  43. 43. Figure 17-9 Oxytocin and breast feeding At the end of pregnancy, oxytocin is responsible for causing uterine contractions to begin labor as well as stimulating the release of milk from the breasts
  44. 44. Take a Break
  45. 45. Figure 17-10 Male reproductive anatomy Testes (gonads): primary genitalia, producing male gamete, and sperm Unlike female, primary male genitalia are external
  46. 46. Figure 17-10 Male reproductive anatomy Accessory genitalia: •penis (spermdelivery organ), •epididymis, •vas deferens, and urethra (sperm ducts) Several accessory glands: prostate gland, seminal vesicles, and bulbourethral glands
  47. 47. The Testes (Testicles)  Paired organs suspended in sac called scrotum, hanging on either side of penis  During embryonic development, testes formed in abdomen; in last three months of development, migrate into scrotum
  48. 48. Epididymis-Ducts of Male Several ducts in male reproductive system: •Epididymis is commashaped duct on posterior and lateral part of testes •Sperm mature here Epididymis
  49. 49. Vas Deferens Runs from epididymis as pair of tubes, one on each side, into abdominal wall and pelvic cavity, medially over urethra and along posterior bladder wall Vas deferens
  50. 50. Seminal Vesicle Seminal vesicle then lead to ejaculatory duct, which then passes through prostate gland and empties into urethra Seminal vesicle
  51. 51. Prostate Gland Chestnut-size gland surrounding urethra just inferior to bladder made up of dense mass of connective tissue and smooth muscle with embedded glands Prostate Gland
  52. 52. Hormonal Control of Male Reproduction  Testosterone most important sex hormone  Before birth, secretion of HCG by placenta stimulates embryonic testes to secrete testosterone, masculinizing fetus
  53. 53. Hormonal Control of Male Reproduction  At puberty, two hormonal changes occur that signal beginnings of maturity  Testosterone secretion by testes increases  Change in relationship between testosterone and GnRH, LH, and FSH
  54. 54. Hormonal Control of Male Reproduction  Testosterone secretion at puberty responsible for obvious physical changes of male secondary sexual characteristic:  Body, facial, pubic hair growth  Deepening of voice  Increased muscle and bone mass
  55. 55. Hormonal Control of Male Reproduction  LH and FSH affect males exactly as they do females  Stimulate gamete development  Controlled same way in males as in females  GnRH released from hypothalamus, which stimulates LH and FSH secretion from pituitary
  56. 56. Ejaculation-Expulsion of Sperm • In order for sperm to leave body during erection, ejaculation, expulsion of semen (sperm and assorted chemicals), must occur • First sperm are made in testes
  57. 57. Ejaculation-Expulsion of Sperm Smooth muscle contracts throughout ducts and glands of male reproductive system and propels sperm from epididymis into vas deferens, and into pelvic cavity As sperm passes seminal vesicles, sugar and chemicals added
  58. 58. Ejaculation-Expulsion of Sperm Sperm and chemicals enter ejaculatory duct, passing though prostate gland, where fluid is added, liquefying semen
  59. 59. Ejaculation-Expulsion of Sperm Semen then passes by bulbourethral glands; adds mucus to semen and protects sperm from acid environment of vagina by secretion of alkaline substance Semen enters urethra and carried outside body
  60. 60. Fertilization of Human Ovum  Female reproductive system not hospitable to sperm and many will not survive journey  If there is an egg waiting to be fertilized, sperm will find egg and attempt to penetrate it for fertilization
  61. 61. Fertilization of Human Ovum  New research suggests that egg is not passive participant in fertilization, but may actually engulf sperm and even choose which to allow inside  Only one sperm will fertilize egg
  62. 62. FINAL EXAM Chapters 15-17 Final Exam Study Guide for Chapters 15-17 available in FILES on CANVAS