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IB Biology Core 6.6: reproduction


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A slideshow for teachers and students of IB Biology

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IB Biology Core 6.6: reproduction

  1. 1. IB Biology6 Human Health and Physiology6.6 ReproductionAll syllabus statements ©IBO 2007All images CC or public domain or link to original material.Jason de Nys
  2. 2. 6.6.1 Draw and label diagrams of the adult male and female reproductive systems Fallopian tubes (also known as oviducts) are named after Gabriel Fallopio They say that he was the discoverer, but really, most of us have been there Think! Which people have not been there?
  3. 3. Bladder Seminal Vesicle Urethra Prostate Cowper’s gland Penis Anus Vas deferensEpididymis pl. Vasa deferentia Testis pl. Testes
  4. 4. 6.6.2 Outline the role of hormones in the menstrual cycle including FSH (follicle stimulatinghormone), LH (luteinising hormone), oestrogen and progesterone. FSH Produced by: Pituitary Gland Stimulates : • follicle growth (well duh!) • oestrogen* secretion • progesterone secretion And a burst of FSH leads to ovulation
  5. 5. LH*Produced by: Pituitary GlandStimulates : Formation of corpus luteum (lutenising….luteum)A burst of LH leads to ovulation(along with FSH) *Lutenising hormone has nothing to do with lutes
  6. 6. Oestrogen*Produced by: Ovary (follicle)Stimulates :• Thickening of endometrium• Secondary sexual characteristics• Inhibits secretion of FSH• Stimulates secretion of LHOestrogens are actually a group of hormones.The one most commonly referred towhen someone mentions“Oestrogen” is estradiol, pictured here  *Oestrogen, Estrogen…Tomayto, tomahto
  7. 7. ProgesteroneProduced by:• Corpus luteum• Placenta when pregnantMaintains:The endometriumInhibits :• Ovulation Because hopefully you• FSH are, or soon will be:• LH
  8. 8. 6.6.3 Annotate a graph showing hormone levels in the menstrual cycle, illustrating therelationship between changes in hormone levels and ovulation, menstruation and thickening ofthe endometrium. Get the poster!
  9. 9. Can you fill the blanks with the correct hormones?What is happening with theendometrium down here?
  10. 10. Excellent animation
  11. 11. 1 - Menstruation2 - Maturing follicle Producing Oestrogen to3 - Mature follicle prepare the endometrium4 - Ovulation5 - Corpus luteum Producing Progeterone to inhibit6 - Deterioration of corpus luteum LH, FSH and more ovulation
  12. 12. The action of Gonadotropin-releasing hormone (GnRH) (alsoprogesterone on the known as Luteinizing-hormone-releasing hormone!) is mentioned in the McGraw Hillhypothalamus to animation below.prevent the release of You are not required to know about thisLH and FSH is a classic hormone for the course, but it would addexample of negative another dimension to your understanding of what is going
  13. 13. 6.6.5 Outline the process of in vitro fertilisation (IVF)1) The woman is treated with hormones so Intracytoplasmic Sperm Injection that multiple ova mature at the same (ICSI) time. This might be the woman planning may be used if the on having the baby, or a donor donating sperm are poor swimmers the eggs2) Ova are harvested by a needle passed through the wall of the vagina and into the ovary to suck the ova out of the follicles.3) Ova are combined with sperm (washed to remove semen) and left to incubate until the zygote has divided into 6-8 cells, or in some cases, until it is a blastocyst IVF Animation4) The embryo is placed into the uterus via a fine tube inserted through the cervix. Typically multiple embryos are inserted at the same time to increase the chance of success.
  14. 14. IVF is often used to overcomeinfertility caused by blockedFallopian tubes. Dye in the pelvic cavityOn the right is a special x-ray Uteruscalled a hydrosalpingogram.A dye is infused through thecervix into the uterus andfrom there it flows throughthe fallopian tubes and into Fallopianthe pelvic cavity. tube filled with dye Tube administering dye via vaginaThis woman is all clear, youcan see the swirls of dyecoming out the ends of hertubes
  15. 15. Other causes of infertility: Female: • Ova not maturing or being released • Abnormality in uterus prevents implantation • Antibodies in cervical mucus impair sperm Male • Unable to achieve an erection or normal ejaculationTwo tailed sperm, • Low sperm count or sperm areunable to swim abnormal with low motility • Blocked vas deferens
  16. 16. 6.6.6 Discuss the ethical issues associated with IVF 1) Multiple blastocysts are usually implanted in an attempt to ensure success. If too many develop into viable embryos, some may be aborted to improve the chance of success of the others Is that murder?
  17. 17. 1) All of the cells in a blastocyst are totipotent untilthe embryo is about three weeks oldSo technically, each of those cells could become anindividual
  18. 18. 2) Children born as a multiple are often of lower birth weight, with the attending health risks3) Parents face more stress coping with multiple births, this can impact on their relationship and on other children
  19. 19. 2) Multiple births do happen naturally as well and since parents with an IVF pregnancy are usually more closely monitored, multiples are usually discovered earlier3) As long as parents are informed of the risks inherent in their choice, they can prepare, and after all, they are prepared to go through the difficulty of IVF to have a child
  20. 20. 4) In some countries IVF is at great financial cost to the patient, putting stress on their family, and leaving them less money to spend elsewhere in the community.5) Any health issues as a result of being an IVF child will also have to be borne by the parents6) People are profiting from administering the procedure and this may blur their medical judgement7) Donors can make a lot of money in some countries, are they being exploited?
  21. 21. 4) And 5) Parents have the right to spend their money as they see fit6) Medical professionals in the field may be doing it for altruistic reasons and not all are compensated beyond a fair amount7) Donors have the right to do as they wish with their bodies, the money can help poor women to get an education or start a business. In many countries donors are not offered money beyond a small amount of compensation for their time and discomfort
  22. 22. Further information: Three of the best sites for IB-specific Biology information. The top link takes you to the PPT by Stephen Taylor