Question

(a) Why is it necessary to separate oxygenated and deoxygenated blood in
mammals and birds?






(b) Explain how the lungs are designed in human beings to maximise the area for
exchange of gases. Why does the air passage not collapse when there is no air in
it?



​

Answer 1

Answer:

(a) Separation of oxygenated and deoxygenated blood allows a highly efficient supply of oxygen to the body. This is especially important in birds and mammals which have high energy needs and constantly use energy to maintain their body.

(b) The lungs contain millions of alveoli which provide a surface for the exchange of gases. An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flattening the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli. The oxygen from the breath diffuses into the blood and carbon dioxide from the blood (brought from all over the body) diffuses out to the air.The trachea has rings of cartilage around it. These rings of cartilage prevent the trachea from collapsing when we breathe out.

Answer 2

Explanation:

(A) In birds and mammals have double circulation system where both the oxygenated and i blood maintains separately.They must separate oxygenated and deoxygenated blood so that circulatory system is more efficient can maintain constant body temperature.

(B)Lungs play a major role in the respiratory system in human beings,a pair of lungs designed in such a way that they are lined with thin membrane,the smaller tube called bronchioles a balloon like structure called alveoli and network of blood capillaries increase the surface area for exchange of gases.