IGCSE Gas exchange in humans

Identify the structures in the image

What causes an increase in the volume of the thorax?

• Abdominal muscles contracting

• Diaphragm relaxing

• External intercostal muscles contracting

• Ribs moving downwards and inwards

How many cells thick is the wall of an alveolus?

• 1

• 2

• 3

• 4

What process is used for the movement of carbon dioxide from the blood into an alveolus?

Identify the structure in the image

Which structure is responsible for making sounds to enable speech?

• Ribs

• Larynx

• Bronchioles

• Diaphragm

How many alveoli are there in each lung?

• 250 thousand

• 250 million

• 250 billion

• 250

Identify the structures coloured red and blue in the image

Identify the blood vessel that carries deoxygenated blood to the lungs

• Pulmonary vein

• Aorta

• Vena cava

• Pulmonary artery

State the structures that protect the lungs