Gas Exchange in Insects

Question 1

What are spiracles? (2)

Answer 1

• Small openings

- Along the thorax and abdomen

Question 2

What are the tracheae? Features? (4)

Answer 2

• Largest tubes in an insect
• Leads away from the spiracles
• Lined with spirals of chitin (keep them open)
• No gas exchange (impermeable to gasses)

Question 3

What are the tracheoles? Features? (4)

Answer 3

• Lead away from the tracheae
• Single greatly elongated cell
• No chitin lining
• Where most gas exchange takes place

Question 4

What are some features of the insect’s gaseous exchange system?

Answer 4

• Vast no. tracheoles (maximise gas exchange)
• Tracheal fluid to limit the gas exchange
• Water moved out of the tracheoles when lying due to build-up of lactic acid - more surface area for gas exchange

Question 5

How do they supply the oxygen needs? (2)

Answer 5

• Mechanical ventilation - Air actively pumped in by movements of thorax and/or abdomen
• Collapsible enlarged tracheae or air sacs (air reservoir)