7.4

Question 1

What is the gas exchange surface that insects use?

Answer 1

Tracheal system

Question 2

What do trachoma contain in insects?

Answer 2

Fluid which gases can dissolve into.

Question 3

What happens (regarding tracheal fluid) when the insect is more active?

Answer 3

The tracheal fluid moves further into the tissue, so gas exchange happens closer the the respiring cells.

Question 4

Diffusion does not supply oxygen to cells quickly enough so what else do insects use to move gases?

Answer 4

Thoracic and abdominal movements.

Question 5

What are spiracles (in insects) and what is their purpose?

Answer 5

Openings along the thorax and abdomen.
Gases diffuse in and out through the spiralled to and from the tracheoles.

Question 6

What is the exchange surface used to obtain oxygen in fish?

Answer 6

Gills

Question 7

Describe the structure of gills, to create a large surface area for gas exchange.

Answer 7

Highly folded into structures called lamellae

Question 8

What are gills in bony fish covered by?

Answer 8

Operculum

Question 9

What is the area just behind the mouth called in a fish?

Answer 9

The buccal cavity

Question 10

Describe the pathway of oxygen in fish.

Answer 10

The mouth opens
Water enters the buccal cavity (because it has increased volume so less pressure than outside)
The mouth closes, internal volume decreases, and the operculum open, forcing water across the gills.
Oxygen diffuses quickly into the blood stream through the gills.

Question 11

Describe the counter-current system in fish.

Answer 11

The blood flows through the lamellae in the opposite direction of the flow of water through the gills.