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Reproduction

Learn about the process of human reproduction, from the production of gametes to the development of a fetus and the birth of a baby. Explore the functions of the male and female reproductive systems, as well as the adaptations and stages of fetal development.

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Reproduction

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  1. Human Reproduction

  2. Sexual Reproduction in Human testis ovary meiosis meiosis sperms eggs (ova) fertilization zygote embryo fetus baby

  3. Male Reproductive System vas deferens (sperm duct) epididymis here testis

  4. Testes • For production of male gametes (sperms) • For production of male sex hormones http://www.youtube.com/watch?v=ZXGcA1IDmlE

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

  6. Testis and epididymis epididymis vas deferens (sperm duct) sperm tubules

  7. Male Reproductive System seminal vesicle secrete seminal fluid prostate gland Cowper’s gland

  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 Seminal Fluid Semen Sperms +

  9. Male Reproductive System urethra penis

  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 oviduct ovary uterus cervix vagina

  12. Functions of Ovary • For production of female gametes (ova/eggs) • For production of female sex hormones http://www.youtube.com/watch?v=a8fgm-zEYjQ

  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 6 - 14 • Lining becomes thicker with increased blood supply • Day 14 : ovulation • Day 14 - 28 • Lining remains thick to ready for implantation of fertilized ovum • Day 28 • No implantation of fertilization ovum • Uterine lining breaks down; menstruation starts • Day 1 - 5 • Menstruation starts • Uterine lining decreases in thickness to a minimum

  17. Sexual Intercourse • View film clip from Architectural Design of Men and Women

  18. Implantation • Fertilized eggs are implanted into thick walls of uterus • Chorion membranes dig into uterus to form placenta • Zygote grows into an embryo • Embryo gets air and nutrients through the umbilical cord • Once pregnant, progesterone levels stay high in mom • Mom’s uterus grows with the baby

  19. 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

  20. Development of Human Foetus uterus fetus placenta umbilical cord amnion amniotic fluid

  21. 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

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

  23. The Placenta oxygenated blood from mother’s artery deoxygenated blood to mother’s vein villus umbilical vein umbilical artery

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

  25. 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

  26. 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

  27. 1st Trimester = 1st 12 weeks • Heart develops first • Neural tube develops • All body systems appear by Week 8 – Now a Fetus

  28. 2nd Trimester = up to 24 weeks • Most growth • Looks more like a baby • Some preemies survive at this stage

  29. 3rd Trimester= Up to 40 weeks • More growth • Kicking, rolling, stretching • Eyes open – Week 32 • Lungs mature • Rotates to head-down position, unless baby is breech

  30. Birth • Labor • Uterine contractions begin • Cervix dilates to 10 cm. • Birth • Uterus pushes baby through vaginal canal • Placenta delivered after baby • Cesarean Section (c-section) is a surgery that cuts through the uterus to deliver the baby if it cannot be born vaginally Mrs. Degl

  31. The Birth Process • Onset of labor • Uterine muscles begin to make rhythmic contractions • Contractions gradually become stronger and closer

  32. The Birth Process • Uterine contractions causes amnion to break and amniotic fluid to escape out of the vagina • Muscular contractions push the foetus head first through the vagina, and the umbilical cord is cut and tied • Further contractions push the placenta out of the body • “After birth” • Dilation of cervix allow the head of the foetus to pass through

  33. Could you survive after birth without the care of your parents?

  34. 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

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

  36. Using contraception methods What can we do?

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

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

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

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

  41. Surgical Methods Tubal ligation Cutting and tying of oviducts Vasectomy Cutting and tying of sperm ducts

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