Gas Exchange In Insects: Tracheal System

Question 1

Movement of oxygen through insects

Answer 1

1) Oxygen enters through spiracles on the body’s surface down a concentration gradient into the tracheae
2) Spiracles close -> maintains the concentration gradient and limits water loss
3) In the tracheae oxygen diffuses faster through the air down the concentration gradient
4) The tracheae branches off into tracheoles where gas exchange occurs
5) Oxygen is delivered directly to the respiring tissues

Question 2

Adaptations of the tracheal system

Answer 2

-Highly branched = large surface area for faster diffusion
-Thin wall/ 1 cell thick = short diffusion distance
-Supply tissues and abdominal pumping = O2 diffuses directly into the cells
-Permeable walls to O2 = Fast diffusion

Question 3

Oxygen diffusion down a concentration gradient

Answer 3

Tissues respire using oxygen, which reduces the concentration at the tissue, oxygen moves from an area of high concentration to lower so moves from tracheae to the tissues which lowers concentration of oxygen in the tracheae so moves from outside the insects into the tracheae through the spiracles

Question 4

Carbon dioxide diffusion down a concentration gradient

Answer 4

Respiration produces CO2 increasing the concentration at the tissue, carbon dioxide moves from high concentrated area at the tissue to a low concentration at the tracheae. It then moves from a high concentration in the tracheae to a low conc outside the insects via its spiracles

Question 5

What is abdominal pumping?

Answer 5

Movement of the insects body by its muscles where they fled their abdomens maintaining a concentration gradient for oxygen and carbon dioxide. Air sacs in the tracheae which when muscles around the tracheae contract pumps the air in the sacs deeper into the tracheoles. Muscle contraction pumped co2 out and o2 through the system

Question 6

How do insects balance efficient gas exchange with water loss?

Answer 6

• A rigid exoskeleton covered by a waterproof cuticle which is impermeable so it reduces water loss
• Spiracles close to prevent water loss
• Small hairs around the spiracles trap water and reduces the water potential

Question 7

What system do insects use for specialised gas exchange?

Answer 7

Tracheal system

Question 8

What is the site of gas exchange in insects?

Answer 8

The tracheoles