Question

Lungs of a man are highly suitable for respiration.why?

Answer 1

In man, there are a pair of lungs present in the thoracic cavity. They are found next to the heart. Towards the front they are protected by the chest wall that is formed by the rib cage and the muscles associated with the ribs. There are 12 pairs of ribs and two sets of muscles called the outer and inner intercostal muscles in the chest wall. Posteriorly, lungs are bound by a muscular diaphragm that separates the thoracic cavity

Lungs are spongy, lobed and elastic organs that are broad at the bottom and tapering towards the top. They consist of air sacs, the alveolar ducts, bronchioles (which connect them to the respiratory tract) and the blood vessels.

Each lung in enclosed by two membranes called the outer and the inner pleural membrane. The membranes enclosed a space called the pleural cavity that contains a fluid. The lungs are capable of expanding and contracting as they are elastic organs. Lubrication for their free movement is provided by the fluid in the pleural cavity.

Respiration takes place in the following stages:
External respiration or gaseous exchange: The exchange of gases between the environment and the body is called external respiration or gaseous exchange.
Internal respiration: The bio-chemical processes involved in respiration which break down the substrate to release energy take place in the tissues within the cells of an organism. Thus, this is also called the cellular or tissue respiration.