Gas Exchange in Insects

Question 1

Process of structures in insect gas exchange

Answer 1

Spiracle → trachea → air sac → tracheoles → muscle fibre

Question 2

What are spiracles

Answer 2

Tiny holes (spiracle) in surface of skin, O2 mechanically pumped into skin

Question 3

Spiracle to trachea

Answer 3

Spiracle leads to trachea that run between cells into muscle fibres (large SA)

Question 4

Trachea size

Answer 4

Size makes them able to diffuse O2 into muscle tissue

Question 5

Movement of insects maintains what

Answer 5

Concentration gradient

Question 6

What do tracheoles do

Answer 6

Tracheoles run deep into body and branch off into many directions directly into muscle cell tissue

Question 7

Why do insects have this gas exchange mechanism

Answer 7

Exoskeleton is impermeable to gases
(Prevents diffusion of gases)
So insects have to be highly active and have high metabolic rate to meet demand for oxygen

Question 8

What do flying insects have compared to non flying ones

Answer 8

Need more rapid O2 intake so have mass flow in tracheal system

Question 9

How do flying insects intake O2 more rapidly

Answer 9

Closing spiracles
Using muscles to pump movement of ventilation

Question 10

What do flying insects have in tracheoles

Answer 10

Water

Question 11

What does the water in the tracheoles do

Answer 11

Water is drawn into respiring muscle so gas diffuses by osmosis quicker
Increasing surface area of gas exchange

Question 12

Trachea tubes made out of

Answer 12

Chitin

Question 13

Advantage of tracheoles

Answer 13

Making them have short diffusion paths by allowing direct exchange of gases with body tissues

Question 14

Explain three ways in which an insect’s tracheal system is adapted for
efficient gas exchange

Answer 14

Short Diffusion Paths:
1. Tracheoles have thin walls = short diffusion distance to muscle cells
2. Large number of tracheoles = short diffusion
distance to cells;
3) Tracheae provide tubes full of air so fast diffusion
4. Fluid in the end of the tracheoles that moves out
during exercise = faster diffusion through the air to the gas
5) Body can be moved to move air so maintains
diffusion / concentration gradient for oxygen / carbon dioxide;

Large SA:
6) Large number of tracheoles
exchange surface and larger surface area

Question 15

What is a spiracle

Answer 15

Opening in exoskeleton of insects which has valves

Question 16

What do spiracles do

Answer 16

Allow air to enter insect and flow into trachea system

Question 17

What are tracheae

Answer 17

Treacheae are tubes in breathing system that lead to tracheles

Question 18

What do tracheoles do

Answer 18

Tracheoles run between cells into muscle fibres

Question 19

Hwo is a concentration gradient formed

Answer 19

As oxygen is used by respiring tissues which allows more oxygen to mvoe in through spiracles by diffsuion
CO2 produced by respiring tissues mves out through spiracles down a concentration gradient

Question 20

What advantages do flying insects have and why

Answer 20

-Need more rapid intake of oxygen
-Close spiracles using muscles to create pumping movement for ventilation
-Lactate produced by respiring muscles lowers water potential of muscle cells -> water at ends of tracheoles is drawn in to respiring muscles by osmosis to allow gases to diffuse across more quickly

Question 21

How does using their muscles to move air into the tracheae increase efficiency of gas exchange

Answer 21

Maintains steep diffusion gradient for O2 and CO2

Question 22

How os the mass flow of air in flying insects made§

Answer 22

Closing spiracles
Using muscles to create pumping movement fr ventilation

Question 23

How is the water loss of flying insects limited

Answer 23

Lactate lowers the water potential of muscle fibres
Water at ends of tracheoles is drawn into respiring muscle by osmosis (high tracheoles to low muscle fibre)
Allows gases to diffuse across more quickly