Sunday, July 24, 2011

Events Following Conception - Part II

This is in continuation with the previous post How Pregnancy Occurs - Events Following Conception - Part I.

On 10-11th day after conception, the process of implantation of the embryo in the wall of the uterus (womb) is completed. By this time it is covered on all sides by the tissue of the uterine wall.

As mentioned in the previous post, the cells on the outer side lead to the formation of placenta and membranes.

Functions of Placenta
  • Provides nutrition to the baby
  • Removes waste products from its circulation
  • Supplies oxygen
  • Forms a protective barrier against certain harmful substances in mother's blood
Membranes also protect the baby from infection and contribute to the formation of amniotic fluid which serves as a shock absorber.

While the outer cells form the protective structures, inner cell develop into the baby.

14-21 days after conception - Neural plate is formed which later forms the nervous system and brain of the child.

21-28 days after conception - Heart becomes prominent

4-6 weeks after conception - Hands and feet begin to appear and the face is formed. Size is about 4-15mm.

6-8 weeks after conception - All major structures have developed and embryo can be recognized as a human. Size reaches about 15-30 mm.

8-12 weeks after conception - External genitals of the baby form. Size of the baby is about 30-60mm.

20 weeks - Fine hairs called lanugo cover the skin.

36 weeks - Lanugo starts to disappear.

40 weeks - Nails project beyond finger tips.

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