Question

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. 1. Umbilical cord
   2. Placenta
   3.  Amniotic fluid
2. Functions of placenta: 
   • It allows the diffusion of oxygen, nutrients and immune products from the mother to the foetus.
   • It allows the diffusion of waste material generated by the foetus to the mother for excretion.
3. Functions of amniotic fluid:
   • The amniotic fluid prevents the foetus from injury and shocks.
   • It allows the foetus some amount of movement.
   • It prevents the amnion from sticking to the foetus.
   • It maintains an even pressure all around the foetus.
4. Gestation:
   • The time period required for the development of the foetus inside the uterus is called gestation. 
   • The normal gestation period in humans is 280 days (9 months).
5. Male sex chromosomes:
   • One ‘X’ chromosome and one ‘Y’  chromosome (XY).
   • Female sex chromosomes: Two ‘X’ chromosomes (XX).