ventilation in insects

Question 1

Why do insects need an adapted transport system?

Answer 1

They need adapted transport systems to take oxygen to tissues because they have:
-a small surface area
-a large volume
-no transport system

Question 2

What are the tracheae?

Answer 2

2 tubes down either side of body to pass air

Question 3

What are the tracheoles?

Answer 3

smaller, branched tubes which take oxygen to tissues

Question 4

What are spiracles?

Answer 4

similar to stomata in plants, they are controlled valves along the body that form the exit point of trachea

Question 5

How many spiracles in an insect?

Answer 5

-maximum of 20- 8 abdominal pairs and 2 thoracic pairs

Question 6

Disadvantages of spiracles

Answer 6

-make insects susceptible to water loss/desiccation

Question 7

How do insects deal with water loss via spiracles?

Answer 7

-close spiracles as much as possible
-air sacs along trachea allow small amounts of oxygen to be stored when this happens for long periods

Question 8

Adaptation of spiracles

Answer 8

-hairs around them to trap humid air, so less water is lost (concentration gradient)

Question 9

How do insects ventilate?

Answer 9

-pump abdomen to draw air in and out of trachea via spiracles
-air moves into tracheoles when at rest, or is drawn in when muscles are contracting
-dissolved oxygen is delivered to muscle fibres by the fluid

Question 10

Why can insects not be bigger?

Answer 10

-more cells=more oxygen demand
-tracheal system can’t meet respiratory demands and supply cells
-mass of exoskeleton would limit movement