Respiration in Insects and Earthworm


 
 
Concept Explanation
 

Respiration in Insects and Earthworm

Earthworm: The earthworm inhabits burrows in damp soil and emerges to feed in the darkness. Gaseous exchange occurs through its skin. The thin moist skin is supplied with a network of capillaries which absorb oxygen from the atmosphere and deliver it to the rest of the body. The absorbing surface or the network of capillaries also eliminate carbon dioxide from the body.

Insects: Some species of insects breathe through the entire body surface by diffusion. Air reaches the various parts and organs of an insect via an elaborate system of branching tubes called tracheae. The tracheae open up on the exterior body surface as spiracles. Most adult insects have two pairs of spiracles on the thorax and eight pairs on the abdomen. Large tracheal tubes run along and across the body. Smaller tracheae branch profusely from these larger ones finally forming tiny tubelets or tracheoles. Oxygen diffuses into the cells at the fine endings of the tracheal system. Carbo dioxide is carried out of the body by tracheoles too.

Grasshoppers and many other insects also have air sacs in their tracheae system. These air sacs function during vigorous body movements, speeding up the movement of gases to and from the tissues. Some insects that live in water (partially or completely) have gill-like structures, found in fish, for breathing.

Fish: Fish absorb dissolved oxygen from the water by means of gills. Fish gulps water through the mouth and forces it between the gills on each side of its head. The blood vessels present in the gills take out dissolved oxygen from the water and send this oxygen to all parts of the body. The oxygen is made use of to produce energy and carbon dioxide. The waste products and the carbon dioxide are transported back by the blood into the gills for throwing out into the surrounding.

Frogs: Exchange of gases in frog, when it is in water, takes place through its thin, moist and smooth skin that is richly supplied with blood capillaries. Frogs also have lungs to respire on land.

Sample Questions
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Question : 1

Which of these have lungs?

Right Option : D
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Question : 2

Earthworms respire through 

Right Option : A
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Question : 3

In cockroach, the tracheal system opens in the outside through

Right Option : D
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