Exchange of Gases Circulatory Module 2

Question 1

how are gases exchanged

Answer 1

Gases such as O2 and CO2 move from high to low concentration or pressure. Oxygen moves from the air in the alveoli across the alveolar/capillary wall into the blood.
At the same time CO2 is moves from the blood into the alveoli across the wall to be breathed out.

Question 2

what do gases do during inspiration

Answer 2

During inspiration the alveoli are supplied with fresh air high in oxygen and low in CO2.
However, the blood in the capillaries arriving at the alveoli is low in oxygen and high in CO2.