Gaseous exchange in insects

Question 1

Tracheal System of an Insect

Answer 1

All insects possess a rigid exoskeleton with a waxy coating that is impermeable to gases
Insects have evolved a breathing system that delivers oxygen directly to all the organs and tissues of their bodies
A spiracle is an opening in the exoskeleton of an insect which has valves
It allows air to enter the insect and flow into the system of tracheae
Tracheae are tubes within the insect respiratory system which lead to tracheoles (narrower tubes)
There are rigid rings of chitin that keep the tracheae open
A large number of tracheoles run between cells and into the muscle fibres - the site of gas exchange
For smaller insects, this system provides sufficient oxygen via diffusion