1 / 33

Reproduction

Reproduction. Topics in Reproduction. (Review) : Reproductive organs. What does what? Fertilisation : The science The female menstrual cycle Birth control in males and females: the pros and cons The placenta Breastfeeding . Questions….For us to discuss on Monday….

edan
Download Presentation

Reproduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Reproduction

  2. Topics in Reproduction • (Review) : Reproductive organs. What does what? • Fertilisation: The science • The female menstrual cycle • Birth control in males and females: the pros and cons • The placenta • Breastfeeding

  3. Questions….For us to discuss on Monday… • What is the future for male contraception – way more than condoms • What are the risks of getting pregnant if you don’t use birth control – on how many days of her cycle can a woman get pregnant? • What preciselydoes drinking alcohol and smoking during pregnancy do to a developing baby? • What are the pros and cons of breastfeeding compared with bottle feeding?

  4. Reproductive organs. What does what? Check the links on the Blog to review anatomy and function!

  5. Female reproductive tract

  6. Male reproductive tract

  7. Asexual reproduction: Binary Fission • animation of binary fission

  8. Asexual Reproduction: Budding Seen in Hydra and other species…

  9. Asexual reproduction: fungal spores…

  10. Why go for sexual rather than asexual reproduction? Links to explain… • From the Natural history museum • A simple explanation

  11. The basic vocabulary of sexual reproduction • Gametes (sex cells) are produced by gonads (sex organs – testes and ovaries) • Gametes are produced through meiosis (reduction division – and have the haploid (n) number of chromosomes • Female gametes are eggs (large, stationary) • Male gametes are sperm (small, motile) • Gametes join together at fertilisation to produce a zygote (diploid number of chromosomes, 2n) • After fertilisation, the zygote grows by mitosis, with the full (2n) chromosome set in every cell

  12. Comparing the ovum and the sperm The egg is the largest cell, while the sperm is the smallest in the human body

  13. Fertilisation and embryonic growth

  14. Male sperm production: produced in the testes under influence of testosterone

  15. Testosterone effects

  16. Romantic relationships and testosterone… According to wikipedia… • Falling in love decreases testosterone in men but increases it in women • Testosterone ‘returns to normal’ after the honeymoon period • Fatherhood decreases testosterone levels • ‘competition’ affects testosterone levels

  17. Sperm are delicate… • Sensitive to heat • Sensitive to environmental oestrogens (Phyto-oestrogens in plants e.g. SOY, Beer), chemicals • Link - environmental oestrogens 'wreck' sperm...

  18. Female egg production: Produced in the ovaries… • Eggs are produced pre-birth • Eggs are arrested in prophase I of meiosis until puberty • From puberty until the menopause, one egg will be produced each menstrual cycle under hormonal control (oestrogen from the overies, FSH and LH from the pituitary gland) • The egg is the largest cell in the body

  19. Female menstrual cycle • An animated version… • …and a detailed diagram • …and a movie!

  20. Hormones of the menstrual cycle

  21. Oral contraceptives interfere with the normal menstrual cycle • Pills exploit feedback controls over hormone secretion • They contain combinations of oestrogen and progesterone OR progesterone only • 100% effective if used properly

  22. Combination pill • They contain combinations of oestrogenand progesterone • You take the hormone pills for 7 days, and then sugar pills for 7 days, long enough for menstruation to occur but not long enough for ova to develop • Combination pills can be monophasic, biphasic or triphasic(dose increasing in 1 or 2 stages)

  23. ‘Mini pill’ • Low-dose progesterone only – for 28 days • Ovulation occurs • Uterus is not favourable for implantation • Less reliable • Safer for older women, breastfeeding women

  24. Side effects of the pill… • Sore boobs • Mood swings • Headaches • Can affect blood pressure • No protection aginst STI’s

  25. Alternatives to the pill for women: contraceptive patch

  26. Alternatives to the pill: contraceptive ring • Hormones (oestrogen, progesterone) released into the vagina • Lower doses of hormones are needed • Just as reliable as the pill • Lower hormone doses so more reliable…

  27. Other methods of contraception: Barrier methods

  28. Natural methods of contraception

  29. Natural methods of contraception: Basal body temperature

  30. Pregnancy!

  31. Hormones: What happens during pregnancy?

  32. Placenta • Baby is called a foetusfrom 8 w, when embryo has all of its major structures • Developing baby is totally dependent on mother for nutrients, oxygen and elimination of wastes • The placentais the specialised organ that performs this role • Placenta also produces hormones to help maintain pregnancy • placenta is joined to foetus by the umbilical cord

  33. Structure of the placenta • Note that foetal blood and maternal blood do not mix • Oxygen and nutrients from the mother diffuse into the capillaries of the chorionic villae • Carbon dioxide and other wastes leave the foetus through the umbilical arteries, pass into the capillaries of the villi and out into the maternal blood

More Related