1. Sexual reproduction in Human beings

2. Learning outcomes Identify on diagrams of the male reproductive system and give the functions of testes, scrotum, sperm ducts, prostate gland, urethra and penis Identify on diagrams of the male reproductive system and give the functions of testes, scrotum, sperm ducts, prostate gland, urethra and penis Identify on diagrams of the female reproductive system and give the functions of ovaries, oviducts, uterus, cervix and vagina Identify on diagrams of the female reproductive system and give the functions of ovaries, oviducts, uterus, cervix and vagina Compare male and female gametes in terms of size, numbers and mobility Compare male and female gametes in terms of size, numbers and mobility Describe the menstrual cycle with reference to the alternation of menstruation and ovulation, the natural variation in its length, and the fertile and infertile phases of the cycle Describe the menstrual cycle with reference to the alternation of menstruation and ovulation, the natural variation in its length, and the fertile and infertile phases of the cycle

3. Learning outcomes: Describe fertilisation and early development of the zygote simply in terms of the formation of ball of cells which becomes implanted in the wall of uterus Describe fertilisation and early development of the zygote simply in terms of the formation of ball of cells which becomes implanted in the wall of uterus

4. Male reproductive organ

5. The male reproductive system Testes (testis) Testes (testis) Organ that produce the gametes and male sex hormone (testosterone) Organ that produce the gametes and male sex hormone (testosterone) The testis constantly divide to produce up to 100,000,000 sperms per day. The testis constantly divide to produce up to 100,000,000 sperms per day. The testis work more efficiently at just below body temperature, so they are held outside the body in scrotum. The testis work more efficiently at just below body temperature, so they are held outside the body in scrotum.

6. The male reproductive system Storage duct/ epididymis Storage duct/ epididymis Sperms are stored in the storage duct temporarily in an inactive form before it enters the sperm duct. Sperms are stored in the storage duct temporarily in an inactive form before it enters the sperm duct.

7. The male reproductive system Sperm ducts/ Vas deferens Sperm ducts/ Vas deferens Tubes which carry the sperm away from the testes Tubes which carry the sperm away from the testes

8. The male reproductive system Seminal vesicle/ Prostate gland Seminal vesicle/ Prostate gland Is about the size of the golf ball Is about the size of the golf ball It adds a nutrient fluid and enzyme (seminal fluid) in which it activates the sperms to swim It adds a nutrient fluid and enzyme (seminal fluid) in which it activates the sperms to swim Sperms + seminal fluid = semen Sperms + seminal fluid = semen

9. The male reproductive system Urethra Urethra The urethra is a tube that carries both urine and semen along the penis to be released from the body but at different times. The urethra is a tube that carries both urine and semen along the penis to be released from the body but at different times.

10. The male reproductive system Penis Penis It is an organ for introducing sperms into the female. It contains spongy tissue which fills with blood to make the penis firm (an erection). It is an organ for introducing sperms into the female. It contains spongy tissue which fills with blood to make the penis firm (an erection).

11. QUICK CHECK! State the functions of: TestesScrotum Sperm ducts Prostate gland Urethrapenis

12. Female reproductive organs

13. The female reproductive system Ovaries Ovaries Female gonads Female gonads Making and releasing the female gametes Making and releasing the female gametes The female releases one ovum every four weeks The female releases one ovum every four weeks

14. The female reproductive system Oviducts/ Fallopian tube Oviducts/ Fallopian tube Are tubes which carry the ova from the ovaries Are tubes which carry the ova from the ovaries They are lined with cilia together with a little muscular assistance, help to move the ova gently along. They are lined with cilia together with a little muscular assistance, help to move the ova gently along. The egg is fertilized in the oviduct. The egg is fertilized in the oviduct.

15. The female reproductive system Uterus/ Womb Uterus/ Womb A pear shape organ A pear shape organ The wall contain involuntary muscle The wall contain involuntary muscle The embryo develops in the uterus during pregnancy The embryo develops in the uterus during pregnancy

16. The female reproductive system Cervix Cervix Cervix is the “neck” of the uterus, where the uterus joins the vagina. Cervix is the “neck” of the uterus, where the uterus joins the vagina.

17. The female reproductive system Vagina Vagina it is part of the female system which receives the penis during the sexual intercourse it is part of the female system which receives the penis during the sexual intercourse It is muscular and stretchable It is muscular and stretchable

18. QUICK CHECK! State the functions of: State the functions of:OvariesOviductsUterusCervixvagina

19. Checkpoint 1: Name the organ/ organs that carry out the function: Store matured sperms Store matured sperms Carries both sperm and urine Carries both sperm and urine Produces cells with only half the number of chromosome Produces cells with only half the number of chromosome Produces the male sex hormone Produces the male sex hormone Receive sperm Receive sperm Egg must be fertilised here for pregnancy to take place. Egg must be fertilised here for pregnancy to take place.

20. Female gametes vs male gametes

21. Male gametes Released in millions Released in millions Able to swim Able to swim Very small (0.05 mm) Very small (0.05 mm) Very little cytoplasm Very little cytoplasm Nucleus contains either an X or a Y chromosome Nucleus contains either an X or a Y chromosome Female gametes Released one per month Released one per month Unable to move by their own Unable to move by their own Comparatively large (0.1mm in diameter) Comparatively large (0.1mm in diameter) A lot of cytoplasm which contains nourishment for the zygote if the ovum is fertilised A lot of cytoplasm which contains nourishment for the zygote if the ovum is fertilised Nucleus always contains an X chromosome Nucleus always contains an X chromosome

22. QUICK CHECK! Compare the human male and female gametes in terms of (i) size, (ii) numbers and (iii) Movement (iv) cytoplasm In each case, suggest reasons for the differences you describe.

23. Human reproductive system Menstrual cycle

24. The average menstrual cycle is about 28 days. The average menstrual cycle is about 28 days. Begins with puberty, ends with menopause. Begins with puberty, ends with menopause. Menstrual cycle consists of 4 phases; Menstrual cycle consists of 4 phases; a.menstrual phase b.proliferative phase c.ovulation phase d.secretory phase.

25. Menstrual cycle Menstrul phase (Day 1 – 5) The spongy lining then peel away, damaging the blood capillaries. The lining passes out of the vagina, together with the blood. Menstrual period. It lasts for about 5 days The spongy lining then peel away, damaging the blood capillaries. The lining passes out of the vagina, together with the blood. Menstrual period. It lasts for about 5 days Follicles containing ovum develops. Follicles containing ovum develops.

26. Menstrual cycle Proliferative phase (Day 6 - 11) Follicles containing egg cell found in ovaries. Follicles containing egg cell found in ovaries. Day 6, one follicle matures and begins to secrete hormone Oestrogen. Day 6, one follicle matures and begins to secrete hormone Oestrogen. Oestrogen level in blood increases. Oestrogen level in blood increases. Oestrogen causes the repair and growth of the uterine lining. The lining becomes thick and spongy with blood vessels. Oestrogen causes the repair and growth of the uterine lining. The lining becomes thick and spongy with blood vessels. High concentration of Oestrogen prevents growth and mature of more follicles. High concentration of Oestrogen prevents growth and mature of more follicles.

27. Menstrual cycle Ovulation Phase (Day 12 - 15) On Day 12 – 13, rapid increase in Oestrogen level. Triggers ovulation (1 mature follicle releases a ovum) on Day 14. The remains of the mature follicle secretes hormone progesterone and little oestrogen.

28. Menstrual cycle Secretory Phase (Day 16 - 28) The remains of the mature follicle secretes hormone progesterone and little oestrogen. Progesterone maintains the uterine lining by causing it to thicken further and be supplied with blood vessels. The thickened lining also begins to secrete nutrients and mucus to prepare for an embryo to be implanted. High level of progesterone ensures no new follicles mature. (ref to the pill)

29. Menstrual cycle Secretory Phase (Day 16 - 28) If the ovum (egg cell) is not fertilised, the remains of the mature follicle will last for about 10 – 12 days, then degenerates. Secretion of progesterone and oestrogen stops The drop in hormone levels causes the uterine capillaries to rupture. Follicles are not inhibited anymore.

30. If Fertilisation takes place.... Secretory Phase (Day 16 - 28) Embryo embeds/implants itself in the uterine lining. Causes the remains of the follicle to continue secreting progesterone.

31. Menstrual cycle Menstrual cycle The fertile period is from day 11 to day 17, because ovulation has occurred. Ovum can survive for 2 days and allowing for the possible survival of sperms in the oviduct. The fertile period is from day 11 to day 17, because ovulation has occurred. Ovum can survive for 2 days and allowing for the possible survival of sperms in the oviduct. The rest of the time is considered infertile period. The rest of the time is considered infertile period.

32. Factors affecting menstrual cycle Severe Stress Severe Stress malnutrition malnutrition Mental fatigue Mental fatigue Severe Illness Severe Illness These factors can alter or stop the menstrual cycle These factors can alter or stop the menstrual cycle

33. Summary

34. Reproduction Fertilization and development of embryo

35. Fertilization The egg released is surrounded by a few layers of follicle cells. The egg released is surrounded by a few layers of follicle cells. The sperm swim toward the egg in the oviduct, it will release enzymes that digest the follicle cells. Only one sperm enters the egg. The sperm swim toward the egg in the oviduct, it will release enzymes that digest the follicle cells. Only one sperm enters the egg. The fusion of the nuclei to form the zygote is called fertilization. The fusion of the nuclei to form the zygote is called fertilization. Fertilization occurs in oviduct. Fertilization occurs in oviduct.

36. Development of embryo The zygote passes along the oviduct to the uterus, assisted by action of cilia, and it begins to divide by mitosis to form a hollow ball of cells called embryo. The zygote passes along the oviduct to the uterus, assisted by action of cilia, and it begins to divide by mitosis to form a hollow ball of cells called embryo. The embryo becomes embedded in the uterine lining. This is called implantation. The embryo becomes embedded in the uterine lining. This is called implantation.

37. Development of embryo placenta Finger –like projections (villi) to provide large surface area for diffusion Finger –like projections (villi) to provide large surface area for diffusion Allow dissolved food substances (glucose, amino acid, mineral salts) and oxygen to diffuse from mother blood to the embryo Allow dissolved food substances (glucose, amino acid, mineral salts) and oxygen to diffuse from mother blood to the embryo Allow metabolic waste (urea and carbon dioxide) to diffuse from embryo to mother’s blood Allow metabolic waste (urea and carbon dioxide) to diffuse from embryo to mother’s blood Allow the antibodies to diffuse to the embryo Allow the antibodies to diffuse to the embryo Produce progesterone Produce progesterone umbilical cord Contain umbilical vein and two umbilical arteries Contain umbilical vein and two umbilical arteries bring dissolved oxygen and nutrients by the umbilical vein to the foetus removing waste via umbilical arteries. bring dissolved oxygen and nutrients by the umbilical vein to the foetus removing waste via umbilical arteries. amniotic fluid Provide the buoyancy to the foetus, thus protect it from shock and mechanical injuries Maintains a relatively constant environment for the foetus.

38. Development of embryo The exchange of the material between the foetus and the placenta. The exchange of the material between the foetus and the placenta. Page 349

39. Exchange of materials across the placenta Mother to fetus Oxygen Oxygen Glucose Glucose Amino acids Amino acids Vitamins, minerals Vitamins, minerals Alcohol, nicotine, many other drugs Alcohol, nicotine, many other drugs Viruses Viruses antibodies antibodies Fetus to mother Carbon dioxide Carbon dioxide Urea Urea Other metabolic waste Other metabolic waste

40. Page 349

41. Development of embryo The time between conception and birth is nine months. The time between conception and birth is nine months. The nine months is known as the gestation period. The nine months is known as the gestation period. At the end of the gestation period, contraction of the uterus walls causes the rupture of the amniotic sac. At the end of the gestation period, contraction of the uterus walls causes the rupture of the amniotic sac. The birth of the baby is followed by the ejection of the placenta. The birth of the baby is followed by the ejection of the placenta.

42. Thinking room? How are identical twins come about? Why do they always - look alike and same sex? How are identical twins come about? Why do they always - look alike and same sex?

43. IVF A woman with blocked oviducts cannot have a baby in the normal way but can now have a ‘test-tube’ baby. A doctor, using a fine tube through the body wall, sucks up several eggs from the ovary, puts them in a dish and mixes them with sperm. The eggs are then kept for a few days before they are put back into the woman’s uterus via the cervix. 1. Describe what can normally happen in the oviduct. a. Why does the doctor get the eggs from the ovary through the body wall and not through the vagina and uterus? b. Why must the sperms be mixed with eggs before they are put back in the woman? c. Why do you think the eggs are kept for a few days before they are put back into the uterus? d. Why is the term ‘test-tube baby’ inaccurate?