Gas Exchange at the Alveoli (Edexcel GCSE Physical Education): Revision Notes

Gas Exchange At The Alveoli

Gaseous Exchange

• Gases move from areas of high concentration to areas of low concentration. If there is more oxygen in the alveoli than the capillaries oxygen will move into the capillaries
• Oxygen is diffused into the blood. It binds with the haemoglobin in the blood to form oxyhaemoglobin
• Oxyhaemoglobin is transported to the working muscles where it is used for aerobic activity
• During aerobic activity carbon dioxide is produced this is removed from the muscles by haemoglobin
• Gaseous exchange occurs at the alveoli capillaries and capillaries – muscle tissue

Features That Assist in Gas Exchange

• Alveoli have very tiny air sacs with moist thin walls (only one cell thick)
• Alveoli have a very large surface area
• Alveoli are surrounded by capillaries
• It provides a large blood supply