Gas Exchange and Transport of gas

Which blood vessel carries deoxygenated blood?

• aorta

• pulmonary artery

• hepatic artery

Where does gas exchange occur?

• air bag

• air sac

• bronchi

• bronchioli

The significance of the water film in air sac is to...

• allow oxygen to dissolve in it for diffusion.

• moisten the incoming air.

• trap bacteria and virus.

• keep temperature in air sac warm.

Oxygen and carbon dioxide diffuse across the wall of air sac by

• active transport

• exocytosis

• osmosis

• diffusion

The wall of the air sac is one cell thick, what is the significance?

• So that many air sacs can be packed in the lung.

• To make the lung elastic.

• To reduce diffusion distance for gas exchange.

• To increase the surface area for gas exchange.

How many layers of cell membrane should a carbon dioxide molecule in blood to pass through to reach air sac's space?

• 3

• 4

• 5

• 6

Read textbook p.14 Practical 8.5 set-up. If I want to blow air to the set-up, which clip should I close?

• left one (connect to X)

• right one (connect to Y)

Dense network of capillaries can be found surrounding the air sac. What is/are the significance(s)?

• To increase the diffusion distance for gas exchange.

• To maintain concentration gradient of oxygen/CO2 steep.

• To increase surface area for gas exchange.

• To shorten the diffusion distance for gas exchange.

Most of the oxygen in the blood is contained...

• by the haemoglobin in the red blood cells.

• in the nucleus of red blood cells.

• in the plasma.

• cell surface of the red blood cells.

Oxyhaemoglobin can be formed by

• reacting haemoglobin with oxide ions.

• reacting haemoglobin with carbon dioxide.

• reacting haemoglobin with oxygen.

• reacting haemoglobin with carbon monoxide.