GAS EXCHANGE - INSECTS

Question 1

What are the structures in the insect gas exchange system?

Answer 1

Tracheae - network of tues, supported by strengthened rings
Tracheoles - fluid-filled dead-end tubes the tracheae divide into; directly connected to body tissues
Spiracles - gases enter and exit trachea through these tiny pores; opened/closed by valves

Question 2

How do respiratory gases move in and out of the GE system (diffusion gradient)?

Answer 2

Oxygen is used up in respiration; creating diffusion gradient. Oxygen diffuses from the atmosphere along the tracheae
Carbon dioxide is produced in respiration; another diffusion gradient is created, carbon dioxide diffuses from tracheae to atmosphere

Question 3

How do respiratory gases move in and out of the GE system (mass transport)?

Answer 3

Muscle contraction in the tracheae causes them to squeeze, increasing the speed of exchange and enabling mass movement of air in and out

Question 4

What are the limitations of the GE system?

Answer 4

The diffusion pathway has to be very short for it to be effective, which is why insects are small creatures

Question 5

How does gas exchange work in single-celled organisms?

Answer 5

Oxygen diffuses into the cell across the cell-surface membrane down the concentration gradient, carbon dioxide diffuses out of the cell, across the cell-surface membrane down a concentration gradient