The purpose of the lungs is mainly to

• allow oxygen into the body

• remove carbon dioxide

• remove water vapour

Normal respiration involves

• the use of intercostal muscles

• the use of a muscular diaphragm

• the use of intercostals and the diaphragm

• something different

The normal oxygen content of inhaled air is approximately

• 0.04%

• 21%

• 79%

• 100%

The normal carbon dioxide content of exhaled air is approximately

• 0.04%

• 4%

• 14%

• 24%

The main tube connecting the mouth to the lungs is the

• alimentary canal

• oesophagus

• trachea

• something els

From the trachea the airway splits into

• brachycardia

• breathers

• bronchioles

• brioche

Specialist cells in the bronchioles have structures on them called

• alveoli

• cilia

• dermacytes

• erythrocytes

Why do you need mucous membranes in the bronchioles?

• to help the food go down smoothly

• to stop the air irritating them

• to help air pass through

• to trap and remove foreign particles

At the end of the bronchioles are structures called

• alveoli

• blastocytes

• villi

• none of these

How are alveoli and villi similar

• they are not

• by cell thickness

• by where they are in the body

• by how they deal with foreign proteins