Insect e.g Locust

• Gaseous exchange takes place through a tracheole system (trachea)
• Air enters or leaves through small openings known as spiracles, found on the thorax and abdomen
• The tracheal system consists of an extensive network (large surface area) of tubes (trachea) that branch throughout the body.
• These trachea become smaller and form tracheoles that branch between tissues. The walls are very thin. They contain a liquid that keeps the walls moist
• O2 diffuses directly from the tracheoles into the tissue cells, while CO2 diffuses from the tissue cells to the tracheoles.
• Air sacs that function as a ventilation system are located near the main muscles. They ensure that air moves quickly to and from the tissues
• The tracheal system is found inside the animal and it therefore protected by surrounding tissues