Gaseous Exchange in Insects

HideShow resource information
Why do insects have a different gaseous exchange system to mammals?
Tough exoskeleton where little/ no gaseous exchange can take place, don't usually have blood carrying pigments in blood (so the oxygen is delivered directly to the cells)
1 of 13
Spiracles
Small openings in the insects exoskeleton, where air enters and leaves and also where water is lost, they can be opened and closed
2 of 13
Sphincters
Things that open and close spiracles in order to control water loss
3 of 13
Tracheae
Tubes leading away from the spiracles, carries air into the body, lined by chitin
4 of 13
Chitin
Keeps the tracheae open, impermeable to gases so little gaseous exchange occurs in the tracheae
5 of 13
Tracheoles
Tracheae branch into tracheoles, a tracheole is a single elongated cell with no chitin so it is fully permeable to gases, they run in between each cell
6 of 13
How does gaseous exchange take place when an insect is resting?
Air moves along the tracheae into the tracheoles by diffusion alone, reaching all the tissues, the oxygen dissolves in the moisture in the walls of the tracheoles and diffuses into the surrounding cells
7 of 13
Tracheal Fluid
Fluid at the end of the tracheoles which limits the penetration of air for diffusion
8 of 13
What happens when there is a high oxygen demand?
A lactic acid builds up, making water move out of the tracheoles by osmosis, exposing more SA for gaseous exchange
9 of 13
How is the extent of gas exchange controlled?
With the opening and closing of the spiracles
10 of 13
Name the 2 alternate ways larger insects increase the level of gaseous exchange
1) Mechanical ventilation of tracheal system, 2) Collapsible tracheae or air sacs acting as air reservoirs
11 of 13
Describe how the Mechanical ventilation tracheal system works
Air is actively pumped into the system due to muscles moving thorax and abdomen, changed volume and pressure so air moves in or forced out
12 of 13
How do the air reservoirs work?
They increase the amount of air moved through the system, inflated and deflated by thorax movements
13 of 13

Other cards in this set

Card 2

Front

Spiracles

Back

Small openings in the insects exoskeleton, where air enters and leaves and also where water is lost, they can be opened and closed

Card 3

Front

Sphincters

Back

Preview of the front of card 3

Card 4

Front

Tracheae

Back

Preview of the front of card 4

Card 5

Front

Chitin

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »