Reproduction

• The menstrual cycle is a recurring process which takes around 28 days. During the process, the lining of the uterus is prepared for pregnancy. If implantation of the fertilised egg into the uterus lining does not happen, the lining is then shed. This is known as menstruation
• Humans reproduce through sexual reproduction. This produces offspring that are genetically unique because half of their genetic material - DNA - comes from each parent.

  Gametes are the male and female sex cells:

  • ova are female gametes
  • sperm are male gametes

  In sexual reproduction, a male and female gamete can join together. This is fertilisation. These gametes are specialised cells which have adaptations to increase the chances of fertilisation and successful development of a baby.
• Ovaries


  • Two in number
  • Contain undeveloped eggs (ova)
  • Make female sex hormones
• Menstrual cycle


  1. Ovum develops

  2. Ovum becomes mature

  3. Ovum is released from ovary

  4. Cilia move ovum along oviduct

  5. Ovum enters uterus
• Oviduct


  • Connects ovary to uterus
  • Lined with cilia (tiny hairs on cells)
• Uterus


  • Muscular bag with soft lining
  • Where baby develops until birth
• Cervix


  • Ring of muscle at lower end of uterus
  • Keeps baby in place during pregnancy
• Vagina


  • Muscular tube leading from cervix to outside of body
  • Where penis goes during sexual reproduction
  • Where menstrual blood leaves body
  • Where baby exits during birth
• A fertilised ovum divides to form a ball of cells called an embryo. The embryo attaches to the lining of the uterus. It begins to develop into a fetus and then becomes a baby when it is born. It takes about 40 weeks for a fetus to develop in the uterus. This time is called gestation.
• After uterus contract. Waves of muscle contractions push the baby out of the mother's body through the vagina. In some cases a caesarean section is performed as a vaginal birth is not possible for health or medical reasons.
• The placenta provides oxygen, nutrients and removes waste products from the developing baby. It also produces hormones that maintain the pregnancy. After birth the placenta is no longer needed so it detaches from the wall of the uterus and passes out of the mother’s body.