gas exchange in insects

Question 1

why has gas exchange evolved in insects

Answer 1

-can be very active so high oxygen demand
-to provide oxygen directly to cells
-CO2 and O2 can’t easily pass through insects’ exoskeleton made of chitin

Question 2

explain how waterproof covering plays a role in insects gas exchange

Answer 2

-A rigid outer skeleton that is covered with a waterproof cuticle to reduce water loss
-Small surface area to volume ratio minimises area over which water is lost

Question 3

explain spiracles in insects gas exchange

Answer 3

-Gas enters and leaves through these tiny pores
-When valves are open water evaporates through them
-Valves are closed for most of the time

Question 4

explain tracheae in the gas exchange of insects

Answer 4

-May be opened and closed by a valve
-Supported by rings of cartilage to prevent them from collapsing

Question 5

explain tracheoles in insects gas exchange

Answer 5

-Extend throughout all the body tissues
-Smaller subdivisions of trachea
-Diffusion gradient causes oxygen to diffuse from the air along the tracheoles to the tracheal fluid

Question 6

explain muscle cells (respiring cells) in insects gas exchange

Answer 6

When cells respire oxygen is used up, so concentration at the ends of the tracheoles falls

Question 7

what happens when insects inspire

Answer 7

•Abdominal muscles relax & body returns to original shape
•Spiracles open
• air pressure inside tracheae lowered, air drawn in.

Question 8

what happens when insect expires

Answer 8

• Abdominal muscles contract
& flatten the body
• volume of the tracheal system decrease
• air pressure inside trachea increased
• air is forced out through spiracles

Question 9

how does tracheal fluid work

Answer 9

-in active tissue lactic acid causes water in tracheal fluid to be drawn in as WP decreases from lactic acid = increases volume in tracheaols for oxygen