The diagram given below is that of a developing human foetus

The diagram given below is that of a developing human foetus. Study the diagram and then answer the questions that follow:

1. Label the parts numbered 1 to 3 in the diagram.
2. Mention any two functions of the part labelled 2 in the diagram.
3. Explain the significance of the part numbered 3 in the diagram.
4. Define the term ‘Gestation’. What is the normal gestational period of the developing human embryo?
5. Mention the sex chromosomes in a male and female embryo.

Answer

1.  1. Umbilical cord
    2. Placenta
    3.  Amniotic fluid                                                                                                                                                                         
2. – Diffusion of O₂ antibodies and nutrients from maternal blood to foetal blood.
   - Diffusion of carbon dioxide, urea, uric acid from foetal blood to maternal blood
   – Acts as a barrier and prevents germs from entering foetal blood
   – Secretes Oestrogen and progesterone                                                                                                                                  
3. 
   – Absorbs mechanical shocks and prevents injury to foetus
   – Keeps foetus moist
   – Maintains even temperature around foetus
   – Allows movement of foetus.                                                                                                                                                             
4. Gestation: It is the full term development of embryo in the uterus 280 days / 40 weeks                                                                                                                                                                      
5. Male - XY
   Female - XX