https://i1.wp.com/www.sciencebold.com/wp-content/uploads/2011/11/8978488.jpg?fit=780%2C729 729 780 admin http://www.sciencebold.com/wp-content/uploads/2016/07/Untitled-300x114.png admin2011-11-28 14:07:002016-09-16 08:07:08Respiration in Animals
In simple organisms such as (amoeba), respiration takes place through the general surface of the body by diffusion process. Diffusion takes places not only in unicellular organisms but also in higher animals, such as hydra and worms. Respiration takes place in earthworm through the general surface of the body wall, which remain moist. This is richly supplied with small blood capillaries.
In insect, such as butterflies, cockroaches, etc respiration takes place through small opening at the side of their bodies, known as spiracles. It leads into a network of branching tubes called trachea, which divide and redivide and pass into each and every tissue of the body.
Fishes breathe through gills. Since fishes live in water, they cannot take oxygen from the air directly. Gills have a rich supply of blood capillaries. Many aquatic animals such as prawn and crab breathe through gills.
In frog, breathing occurs through their moist skin and also through lungs. But in tadpole, breathing occurs through gills.
In reptiles, birds and mammals, respiratory system is highly developed. They respire through lungs.
In human beings, respiratory system is well developed. Firstly, air is taken through nose and the mouth. Then this air passes down through the trachea into lungs. Each lung has a large number of air sacs or alveoli, which is richly supplied with capillaries. Exchanges of gases take place between the blood and air in the lungs. The haemoglobin present in blood helps to transfer of oxygen in our body.