Breathing In Other Animals

Respiration of Class 7

Animals such as elephants, lions, cows, goats, frogs, lizards, snakes, birds, have lungs in their chest cavities like the human beings.

How do other organisms breathe?

Do they also have lungs like those of human beings? Let us find out.

Cockroach:

A cockroach has small openings on the sides of its body. Other insects also have similar openingsThese openings are called spiracles . Insects have a network of air tubes called tracheae for gas exchange. Oxygen rich air rushes through spiracles into the tracheal tubes, diffuses into the body tissue, and reaches every cell of the body. Similarly, carbon dioxide from the cells goes into the tracheal tubes and moves out through spiracles. These air tubes or tracheae are found only in insects and not in any other group of animals.

Earthworm:

The earthworm is land animal. Its respiration, however, is more similar to that of a simple aquatic animal. The earthworm does not have any special respiratory organs like gills or lungs.In earthworm respiration occurs by diffusion of gases through the general body surface, that is, skin. the skin is thin, moist and easily permeable to gases.The oxygen is absorbed through the skin and is transported to the various tissues by the blood. The carbon dioxide produced during respiration is also picked up by the blood from tissues and brought to the skin. From the skin, carbon dioxide is expelled into the outer atmosphere. Under natural conditions where the earthworm lives, the skin is always kept moist by the exudation of coelomic fluid from the body and also by the damp or wet soil. The gaseous exchange is arrested if the skin is dried and the earthworm dies due to asphyxia.

FISH:

Fish are aquatic animals and for respiration they depend on the oxygen dissolved in water. They also release carbon dioxide into water. For this exchange, they have special respiratory organs called gills. Gills are thin, moist membranous structures that are richly supplied with blood.There are four gills on each side of the body. These four gills are enclosed in a gill chamber. The gill chamber is enclosed by a gill cover called operculum.Each gill bears a double row of many fine filaments called gill filaments. The gill filaments bear smaller filaments which in turn, divide into smaller branches. So a very large surface area is provided for gaseous exchange when the gills are immersed in water.The gill filaments are richly supplied with blood capillaries. Exchange of gases takes place through the thin walls of the gill filaments. During breathing, rhythmic movements of the mouth, throat and operculum allow continuous availabilty of water to the gills.Blood in capillaries of gill filaments flows in opposite direction to the flow of water over the surface of filaments. This counter current system greatly helps in gaseous exchange as steep concentration gradient of gases is maintained throughout the respiratory surface resulting intoefficient gas exchange mechanism.

breathing revision