Sexual Reproduction in Human

2. Sexual Reproduction in Human

3. Male Reproductive System

4. Testes For production of male gametes (sperms) For production of male sex hormones

5. Epididymis For temporarily storage of sperms During copulation, muscles of epididymis contract to release sperms

6. Testis and epididymis

8. Functions of Seminal Fluid To provide a medium for the sperms to swim To activate and nourish the sperms To neutralize the acidity in the female reproductive tract

10. Penis Erected during copulation for insertion into vagina Dilation of arterioles causes the erectile tissue of penis become turgid Muscles of epididymis contract Semen is squeezed from the penis to the top of vagina Ejaculation

11. Female Reproductive System

12. Functions of Ovary For production of female gametes (ova/eggs) For production of female sex hormones

13. Oviduct Carries the ovum forward by the beating action of the cilia on its inner surface the contraction of muscles of oviduct

14. Ovulation The release of an ovum from an ovary

15. Menstrual Cycle Once in about 28 days The uterine lining becomes thickened 14 days after ovulation to prepare for the fertilized ovum to implant in it

16. Menstrual Cycle Day 1 - 5 Menstruation starts Uterine lining decreases in thickness to a minimum

17. Events Happened after Fertilization Ovum is fertilized at the oviduct Fertilized ovum is carried to the uterus by the beating cilia on the inner wall of oviduct the contraction of muscles of oviduct After reaching the uterus, the fertilized ovum fixed firmly onto the thick uterine wall ?Implantation

18. Development of Human Foetus

19. Functions of the Uterus During embryo development Protect the embryo Provide a constant environment for the embryo to develop Allow placenta to attach on During birth of baby Push the baby out by muscular contraction

20. Functions of the Amniotic Fluid To keep the foetus moist to prevent dessication As a water cushion to support the foetus allow it to move freely absorb shock protect the foetus from mechanical injuries To reduce temperature fluctuation To lubricate the vagina during birth

21. The Placenta

22. Functions of the Placenta As a place of exchange of materials between mother and the foetus For secreting hormones

23. Adaptations of the Placenta Finger-like villi to increase the surface area for efficient diffusion Maternal blood and foetal blood flows in opposite direction to speed up diffusion of materials between them Maternal blood capillaries and foetal blood capillaries are separated by thin membrane to shorten the distance of diffusion of materials

24. Adaptations of the Placenta Maternal blood is separated from foetal blood by capillary wall to prevent high pressure of maternal blood to break the delicate foetal blood vessels to prevent harmful substances to enter the foetus to prevent clotting of maternal and foetal blood if their blood groups are incompatible

25. The Birth Process Onset of labour Uterine muscles begin to make rhythmic contractions Contractions gradually become stronger and closer

26. The Birth Process Dilation of cervix allow the head of the foetus to pass through

28. Parental Care To increase the chance of survival of the young Mother feeds milk to the baby Milk provides the babies with a balanced diet It also contains antibodies which defend the babies against infection

29. Birth Control Human population increases exponentially leads to storage of resources problem of pollution becomes more serious overcrowding

31. Rhythm Method Prevent copulation during 7 days before and after ovulation (fertile period)

32. Condom Male and female condom As a barrier to prevent sperms from entering the vagina

33. Diaphragm Fitted over the cervix To be used together with spermicides

34. Contraceptive Pills Contains hormones which inhibit ovulation Must be taken regularly May have side effect

35. Surgical Methods