Disaster Management in Fisheries (1+1)

 Respiration

Respiration means breathing in and breathing out of air. This function is necessary to supply oxygen (of the air) to all the organs in the body. Stoppage of oxygen supply to the organs results in death, sooner or later.

The Respiratory System

The organs connected with respiration are the Air Passages and the Lungs:

The Air Passages

The air passages consist of the nose, the throat (pharynx), the wind pipe (trachea) and the two air tubes (bronchi). The bronchi divide into minute branches (bronchioles) which end in the lung substance (alveoli)

The Lungs:

The Lungs are two in number and are situated on the right and left sides of the chest cavity. Each Lung is made up of a number of small sacs called alveoli. The Lung is covered with a membrane called pleura, which lines the inner wall of the chest cavity also.

The Mechanism of Respiration:

During inspiration (breathing in) the diaphragm (the muscle separating the chest cavity) flattens and increases the chest capacity from above downwards. The ribs move upwards and forwards increasing the capacity of the chest cavity from front to back by the action of the muscles situated between the ribs. The lungs thus expand and air enters them.

During expiration (breathing out) the reverse process takes place. The diaphragm comes back to its original state and ribs fall back, thus forcing the air out of the lungs.

Small blood vessels (capillaries) surround the alveoli and the exchange of oxygen and carbon dioxide takes place takes place through the blood circulating in the capillaries. Oxygen is absorbed from the blood and water vapour and carbon dioxide are let out from the blood plasma in to the alveoli.

The lungs are also supplied with nerves that are connected to an area in the brain called the Respiratory Centre. This centre controls respiration.

Suffocation (Asphyxia)

Asphyxia is a condition in which the lungs do not get sufficient oxygen supply of air for breathing. If this continues for some minutes breathing and heart action stops and death occurs.