Describe/ explain the mechanism of gaseous exchange in insects.

Inhalation/inspiration/breathing in.
-Abdominal muscles relax making the tracheal system and the abdomen to expand;
-This increases the volume of the tracheal system; decreasing pressure;
-The spiracle valves open and air rushes in after which the valves close;
-Air is forced into the trachea; and finally into the tracheoles; by muscle movements.
-Oxygen diffuses into watery fluid in the tracheoles; and finally into the cells;
-Carbon (IV) oxide which is at higher concentration within the cells; diffuse into the fluid in the tracheoles and then into tracheal system;
Exhalation/breathing out/expiration.
-Abdominal muscles contract; reducing the volume of the tracheal system; increasing pressure within the tracheal system;
-This forces air from the tracheoles; to the trachea; and out through the spiracles;