Gas exchange in insects

Question 1

What is the mechanism of gas exchange in insects

Answer 1

abdomen movement
fluid movement

Question 2

what are the 3 sections, in order, of an insect

Answer 2

Head
Thorax
Abdomen

Question 3

components of the insect tracheal system

Answer 3

Spiracles, thracheae, tracheoles

Question 4

Spiracles?

Answer 4

Openings in the side of insects

Question 5

Tracheae

Answer 5

Air tubes following on from spiracles

Question 6

Tracheoles

Answer 6

smaller air tubes following on from tracheae

Question 7

How many spiracles are on the abdomen

Answer 7

6-8

Question 8

How many spiracles on thorax

Answer 8

2-4

Question 9

how does the tracheal system affect SA

Answer 9

Increases SA for efficient gas exchange

Question 10

By what mechanism do small insects exchange gases throught spiracles

Answer 10

simple diffusion

Question 11

Through what mechanism do large insects exchange gases throught the spiracles

Answer 11

Ventilation of their tracheal system by rhythmical body movements

Question 12

Described the process of ventilation

Answer 12

Abdomen expands andd thoracic spiracles open
Air enters thoracic spiracles
Abdomen contracts and forces air out through the open abdominal spiracles

Question 13

Why do insects have valves over their spiracles

Answer 13

To reduce water loss

Question 14

When do spiracles open in relation to concentration of gases in the body

Answer 14

When there is a high conc of CO2

Question 15

Why do spiracles open when CO2 conc is high

Answer 15

So CO2 diffuses out and O2 in quickly bc of the steep conc gradients created

Question 16

What do tracheoles branch into

Answer 16

Into cell (muscle) or on their surface

Question 17

What lines the tracheae

Answer 17

chitin

Question 18

Why are tracheae chitin lined 2x

Answer 18

Strengthen them, makes them impermeable to gas so gas exchange doesnt happen here

Question 19

At what point in the tracheal system do gases cross into the cells

Answer 19

At the tracheoles which lead into cells

Question 20

Does O2 diffuse faster through liquid or gas

Answer 20

Gas

Question 21

What are the conditions of the tracheoles when the insect is at rest

Answer 21

Full of water

Question 22

What is the condition of the tracheoles when the insect is active

Answer 22

Water is withdrawn into the surrounding cells

Question 23

Why does water withdraw into cells from tracheoles when insect is active

Answer 23

Production of lactic acid via anaerobic respiration reduces the water potential of the cells

Question 24

How does the water being withdrawn from he tracheoles affect the rate of diffusion

Answer 24

Increases it

Question 25

How do insects reduce water loss 2

Answer 25

Spiracles have valves Exoskeleton made of a thin waxy layer over chitin and protein

Question 26

Limitation of tracheal system

Answer 26

Diffusion is only efficient over short distances, limits insect size

Question 27

How do earth worms do gas exchange

Answer 27

Through the skin though they have a circulatory system to deliver oxygen to the tissues-

Question 28

Benefit of having an impermeable external cuticle layer?

Answer 28

Reduces moisture loss

Question 29

Why cant insects be larger

Answer 29

Trachea would need to be longer, increases diff distance Diffusion would be too slow to provide sufficient O2 to repairing cells Would req more tracheoles, more chitin, more mass: too heavy

Question 30

why dont insects have respiratory pigments

Answer 30

bc the blood doesnt transport the O2 so there is no need.

Question 31

Purpose of air sacks in insects tracheal system

Answer 31

Provide a store of air for when spiracles are closed