Pathway of air and gaseous exchange

Mouth/nose

Air is breathed in. They warm, moisten and filter the air.

Trachea

Directs air into the bronchi

Bronchi

The left and right tube which takes air into each lung

Bronchioles

Occur when bronchi split into smaller tubes in the lungs

Lungs

Located as a pair; left and right, in the chest cavity

Alveoli

Tiny air sacs at the end of the bronchioles with a large surface area

Ribs and sternum

Protect the lungs

Capillaries

very thin (one cell thick) blood vessel which surround the alveoli in a large numbers

Gaseous exchange

occurs in the alveoli

Haemoglobin

Combines with oxygen inside the red blood cells. Can also carry carbon dioxide

Oxyhaemoglobin

When oxygen and haemoglobin combine

Carbon dioxide

Will be high concentration in the blood as a bi-product of muscles working. Needs to be breathed out.

Oxygen

High concentration in the alveoli and needs to move into the blood

Diffusion

All gases move from high to low concentrations

Short diffusion pathway

A very short distance for gases to travel during gaseous exchange

Large blood supply

A key feature to assist in the process of gaseous exchange