Lec65(reproductive system)


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Lec65(reproductive system)

  1. 1. Contraception<br />Pregnancy <br />
  3. 3. Hormonal Suppression of Fertility-"The Pill."<br />3<br />Administration of either estrogen or progesterone during the first half of the monthly cycle, can inhibit ovulation.<br />The drug is usually begun in the early stages of the monthly cycle and continued beyond the time that ovulation would normally occur. <br />Ovarian follicles do not develop and menstrual flow is much reduced<br />
  4. 4. BarrierA. CONDOM<br />4<br />
  5. 5. BarrierB. A DIAPHRAM &SPERMICIDE JELLY<br />5<br />
  6. 6. Female Fertility<br />The ovum capable of being fertilized after ovulation no longer than 24 hours<br />A few sperm can remain fertile in the female reproductive tract for up to 5 days<br />For fertilization to take place, intercourse must occur sometime between 4 and 5 days before ovulation<br />
  7. 7. Rhythm method:<br />Avoid intercourse near the time of ovulation if periodicity of menstrual cycle is 28 d, then ovulation should be day 13-15<br />
  8. 8. Surgical Methods<br />Sterilization<br />Female<br />Tubal ligation is a surgical procedure that seals the fallopian tubes to block sperm.<br />Male<br />Vasectomy is the cutting and tying off of both vasa deferentia. <br />
  9. 9. SPERMICIDE GEL<br />9<br />
  10. 10. INTRAUTERINEDEVICE {IUD}<br />10<br />Plastic or metal device is inserted into the uterus and prevents the young embryo from implanting<br />
  11. 11. Abortion: is the termination of pregnancy that is in progress<br />Mifepristone (RU-486), abortion pills, enables a women to end pregnancy during its first 7 weeks<br />
  12. 12. Pregnancy: Refers to the events that occur from the time of fertilization (conception) until the infant is born <br />Conceptus: The developing offspring<br />Embryo: From fertilization through week 8 <br />Fetus: From week 9 through birth<br />Infant: At birth<br />
  13. 13. Fertilization<br /><ul><li>The oocyte is viable for 12 to 24 hours after ovulation
  14. 14. Sperm cells must make their way to the uterine tube for fertilization to be possible</li></li></ul><li>Fertilization<br />Sperm transport an capacitation: Secretions of the female tract cause some of the sperm membrane proteins to be removed<br />
  15. 15. Acrosomal reaction and sperm penetration<br />Hyaluronidase on the sperm digest the intercellular between granulosa cells<br />The sperm head binds to ZP3 glycoprotein of the zona pellucida<br />Acrosomal reaction involves release of acrosomal enzyme that digest holes in the zona pellucida<br />Acrosomal process binds to the oocyte’s sperm binding receptor<br />Content of the sperm enter the oocyte cytoplasm<br />
  16. 16.
  17. 17. Mechanisms of Fertilization<br /><ul><li>The membrane of the oocyte does not permit a second sperm head to enter
  18. 18. The oocyte then undergoes its second meiotic division
  19. 19. Fertilization occurs when the genetic material of a sperm combines with that of an oocyte to form a zygote</li></li></ul><li>Completion of meiosis II and fertilization<br />
  20. 20. The Zygote<br /><ul><li>First cell of a new individual
  21. 21. The result of the fusion of DNA from sperm and egg
  22. 22. The zygote begins rapid mitotic cell divisions
  23. 23. The zygote stage is in the uterine tube, moving toward the uterus</li></li></ul><li>Events of embryonic development: Zygote to blastocyst implantation<br />Events of the early embryonic period<br />Cleavage, which produces a structure called blastocyst<br />Implantation of blastocyst<br />
  24. 24. Cleavage and blastocyst formation<br /><ul><li>The embryo first undergoes division without growth
  25. 25. Three days after fertilization, a loose collection of cells of 16-cell or more called morula
  26. 26. The embryo floats free in the uterus by 3 or 4 days after fertilization that consist of 100 cells
  27. 27. Blastocyst is a fluid filled hollow sphere composed of a single layer of large flattened cells and a small cluster of 20 – 30 rounded cells</li></li></ul><li>Development from Ovulation to Implantation<br />
  28. 28. Implantation of blastocyst<br />Implantation begins 6 – 7 days after ovulation<br />The trophoblast cells overlying the inner cells mass adhere to endometrium<br />The trophoblast then proliferates and forms inner layer called cytotrophoblast <br />
  29. 29. The outer layer lose their plasma membrane and form syncytiotrophoblast<br />The implanted blastocyst is covered over and sealed off from the uterine cavity by proliferation of the endometrial cells<br />
  30. 30. Implantation of the blastocyst<br />
  31. 31. <ul><li>The trophoblast cells secretes human chorionic gonadotropin (hCG) to promote the corpus luteum to continue producing hormones
  32. 32. Blood levels of hCG rise until the end of second month, then decline by 4 months till the remainder of gestation
  33. 33. All pregnancy tests used are antibody tests that detect hCG in women’s blood or urine</li></li></ul><li>FEMALE HORMONES DURING PREGNANCY<br />Note high levels of estrogen and progesterone.<br />
  34. 34. Placentation<br />Refers to the formation of a placenta, a temporary organ that originates from both embryonic and maternal tissues<br />
  35. 35. Placentation<br /><ul><li>Chorionic villi (projections of the blastocyst) develop
  36. 36. Cooperate with cells of the uterus to form the placenta
  37. 37. The embryo is surrounded by the amnion (a fluid filled sac)
  38. 38. An umbilical cord forms to attach the embryo to the placenta</li></li></ul><li>
  39. 39.
  40. 40. Development After Implantation<br />Figure 16.16<br />
  41. 41. Functions of the Placenta<br /><ul><li>Forms a barrier between mother and embryo (blood is not exchanged)
  42. 42. Delivers nutrients and oxygen
  43. 43. Removes waste from embryonic blood
  44. 44. Becomes an endocrine organ (produces hormones) and takes over for the corpus luteum</li></li></ul><li>