Human Reproduction

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Human Reproduction

  1. 1. Human Reproduction<br />Chapter Four<br />
  2. 2. Sexual Reproduction in Animals<br />
  3. 3. Sexual Reproduction<br />Sexual reproduction is the reproduction that involves the fusion of two gametes or sex cells.<br />The male gametes are called sperms and are produced in the testes.<br />The female gamete is called ova and are produced in the ovaries.<br />
  4. 4. Formation of Zygote<br />Normal body cells have a diploid number of 46 chromosomes.<br />Gametes have the haploid number of 23 chromosomes.<br />When the gametes fuse together, they form a zygote. It will then have the diploid number of 46 chromosomes.<br />The zygote will divide further by cell division or mitosis.<br />
  5. 5. Human Cycle<br />
  6. 6. The Male and Female Gametes or Sex cells<br />
  7. 7. The Sperm – components <br />HEAD<br />Acrosome of digestive enzymes for breaking down of cell membrane of ovum.<br />Haploid nucleus of 23 chromosomes.<br />MIDDLE-PIECE<br />Mitochondria to produce energy for movement.<br />TAIL<br />Beating movement or flagellum for propulsion<br />
  8. 8. The Sperm – other adaptations<br />STREAM-LINED BODY SHAPE<br />Enables efficient swimming<br />LIGHT AND SMALL<br />Enables fast movement<br />
  9. 9. The Ovum – components <br />CYTOPLASM<br />Storage of food to enable ovum to survive while awaiting fertilisation<br />NUCLEUS<br />Haploid nucleus of 23 chromosomes<br />OUTER VITALLENE MEMBRANE<br />Hardens after one sperm has penetrated to prevent multiple fertilisation<br />
  10. 10. The Ovum – other adaptations<br />LARGE SIZE<br />Enables sufficient food storage<br />PLASMA CELL MEMBRANE<br />Enables certain materials into the cell<br />
  11. 11. Parts of the Reproductive System<br />
  12. 12. Male Reproductive System<br />
  13. 13. Penis and Erectile tissue<br />An erectile organ and contains erectile tissue.<br />The tissue inside contains spaces to be filled with blood, turning it erect and hard.<br />This enables it to enter the vagina during sex to deposit semen containing sperms.<br />
  14. 14. Urethra and Semen<br />A tube which passes from the bladder to the outside of the body.<br />Semen and urine passes through it to go out of the body at different times.<br />During ejaculation or release of semen, urine does not come out due to the sphincter muscle controlling it. <br />
  15. 15. Testis and Epididymis<br />Is egg-shaped which produces sperms and male sex hormones called the testosterone.<br />Receives blood from blood vessels in a spermatic cord.<br />Beside each testis lies the epididymis which stores inactive sperms from the testis before entering the sperm duct.<br />
  16. 16. Sperm duct and Seminal vesicle<br />Loops over a ureter and opens up to a uretra. Sperms travel through it after being released from the testes.<br />The seminal vesicle is a gland that opens into each sperm duct.<br />It stores sperms before they are released through the urethra.<br />
  17. 17. Cowper’s , Prostate & other glands<br />Prostate gland is at the base of the urinary bladder where two sperm ducts join the urethra. Cowper’s gland is located beneath.<br />Secrete a slippery fluid which mixes with the sperms.<br />It nourishes the sperms and stimulate them to swim actively.<br />
  18. 18. Female Reproductive System<br />
  19. 19. Ovary and Oviduct<br />They produce eggs and female sex hormones, which are responsible for development of secondary sexual characteristics.<br />When the eggs become mature, they are released from the ovaries.<br />The egg is usually fertilised in the oviduct.<br />
  20. 20. Uterus<br />Also known as the womb, it is where the fetus or embryo develops during pregnancy.<br />The uterus has elastic muscular walls with smooth muscular tissues to push the embryo out during birth.<br />The inner lining of the uterus is the uterus lining that is used for implantation.<br />
  21. 21. Cervix and Vagina<br />The circular ring of muscle at the narrow end of the uterus is the cervix.<br />It enlarges to allow passage of the fetus during birth.<br />Semen is deposited in the vagina during mating through through the opening called the vulva.<br />
  22. 22. Puberty and The Menstrual Cycle<br />
  23. 23. Puberty<br />Puberty is the stage of human growth and development in which a person becomes physical mature.<br />The body begins to change from a child to adult. It begins at 11 for girls and 14 for boys.<br />The reproductive system begins to function. The sex organs mature and start producing gametes.<br />
  24. 24. Changes at Puberty<br />In boys<br />Facial hair, pubic hair, and armpit hair starts growing<br />The penis and testicles increase in size.<br />Production of sperms starts.<br />Voice box enlarges and voice deepens<br />IN GIRLS<br />Pubic hair and armpit hair starts growing.<br />Breasts and uterus enlarge, hips broaden.<br />Menstruation and ovulation start.<br />
  25. 25. Menstruation<br />Menstruation refers to the monthly discharge of blood from the uterus via the vagina.<br />The menstrual period lasts for about 5 days.<br />Menstruation is part of a cycle of events in the female reproductive organ called the menstrual cycle.<br />The average menstrual cycle from an adult woman is 28 days.<br />
  26. 26. The Menstrual Cycle<br />Menstruation in which uterine lining is discharged or broken down. (Day 1 – 5)<br />Growth, thickening and repair of uterine lining. (Day 6 – 10)<br />Fertile period, sperms likely to cause fertilisation (Day 11 – 17)<br />Ovulation in which an ovum is released into the fallopian tube from the ovary. (Day 13 – 15)<br />
  27. 27. Fertilisation to Implantation of embryo<br />
  28. 28. Sexual intercourse in fertile period<br />Ovulation occurs and mature eggs are released from the ovaries.<br />One of the ovum fuses with a sperm to form a zygote through fertilisation.<br />Formation of an embryo, hollow ball of cells.<br />Implantation of embryo in the uterine lining.<br />Placenta, amniotic fluid in amniotic sac and the umbilical cord form after implantation during the embryo development.<br />
  29. 29. Development of embryo<br />Amniotic fluids in amniotic sac supports and protects the embryo, allowing it to move freely.<br />Placenta allows diffusion of oxygen, food substances, antibodies and excretory products to and from the embryo’s and mother’s blood.<br />Umbilical cord transports deoxygenated blood from the embryo to placenta and food substances from the placenta to embryo.<br />
  30. 30. When Fertilisation does not occur<br />The ovum breaks down together with uterine lining on the 28th day.<br />The ovum is discharged with the blood in menstruation through the vagina.<br />This marks the start of menstruation and the whole cycle is repeated.<br />
  31. 31. END<br />

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