Fertilization

• Fertilization: The fusion of an ovum and a sperm to form a zygote.
• Development of zygote:

  • One sperm penetrates
  • Ovum membrane alters to form barrier against sperm
  • Head of sperm (male nucleus) approaches and then fuses with the nucleus of the ovum.
  • Zygote divides over and over, to make a ball of cells called an embryo.
  • It implants itself in the wall of the nucleus (implantation) which is followed by conception
• Development of foetus: zygote is changed through growth (mitosis) and development (organization of cells into tissues and organs)
• Umbilical cord: contains umbilical artery which carries deoxygenated blood and waste products from foetus to placenta and umbilical vein which carries oxygenated blood and soluble food from placenta to foetus. (Contains foetus’ blood)
• Placenta: organ for exchange of soluble materials such as foods, wastes and oxygen between mother and foetus; physical attachment between uterus and foetus. (Contains mother’s blood)
• Amniotic sac: membrane which encloses amniotic fluid, broken at birth.
• Amniotic fluid: protects foetus against mechanical shock, drying out and temperature fluctuations