Write a brief note on tracheal respiration in insects.
A. 1) In insects blood has no haemoglobin and is white in colour. Hence it cannot carry oxygen.
2) For respiration insects adopt a special system called tracheal system.
3) This system consists of a series of tubes called trachea.
4) These trachea open out through small apertures called spiracles on either side of the body.
5) All tracheal tubes of each side join and form a longitudinal tracheal trunk.
6) Trachea divide into a number of branches called tracheoles which carry air directly to the tissues.
7) As the air moves in and out of the trachea, oxygen present in the air diffuses into
the cells and C09 diffuses into the air from the cells.