ILO 2: describe and explain the process of gaseous exchange at the alveoli

what kind of transport mechanism is required for small soluble molecules to be transported across the alveoli

simple diffusion

explain simple diffusion

molecules can freely move throught the cell membrane from a high to low concentration

describe and explain the role of pulmonary surfactant

alveoli contains surfactant (liquid surrounding alveoli) which helps to prevent alveoli collapsing during expansion

describe and explain the process of gaseous exchange within the human lungs

Deoxygenated blood from the pulmonary artery enters the capillaries. Driven by the gradient:

• Carbon dioxide is lost from the blood into the alveoli.

• Oxygen moves into the blood from the alveoli.

The resulting oxygenated blood returns to the heart via the pulmonary vein, and the carbon dioxide is exhaled.