The diagram given below is that of a developing human foetus. Answer the questions that follow: The diagram given below is that of a developing human foetus. Answer the questions that follow:
Mention any two functions of the part labelled 2 in the diagram.
Topic: Functions of the placenta
Answer
- It supplies the foetus with NUTRITION AND OXYGEN from the mother’s blood.
- It removes the WASTE PRODUCTS of the foetus — carbon dioxide and nitrogenous wastes — into the mother’s blood for disposal.
(Also acceptable: it secretes hormones such as progesterone and oestrogen that maintain pregnancy.)
Two functions, and the neatest pair is the two DIRECTIONS of exchange — in and out.
THE POINT MOST OFTEN GOT WRONG: the blood of the mother and that of the foetus DO NOT MIX. They flow close together, separated by a thin membrane, and substances cross by diffusion. Writing that the mother’s blood flows into the baby is a definite error.
The placenta does the work of several organs at once — lungs, digestive system, kidneys and an endocrine gland — because none of the foetus’s own organs is yet functioning.