Scene 1 (0s)
Gas Exchange and Pathway in the Circulatory System.
Scene 2 (7s)
When we breathe in, air goes through the nose and mouth, to the pharynx, larynx, trachea, bronchi and bronchioles to the lungs.
Scene 3 (19s)
Oxygen diffuses from alveoli to the blood vessels to be carried by red blood cells..
Scene 4 (28s)
Oxygenated blood enters the heart through pulmonary arteries to the left atrium, then the left ventricle, and leaves through the aorta, to be distributed to the body cells..
Scene 5 (40s)
When blood reaches the body cells, oxygen diffuses from blood vessels to the cells to be used for respiration. Carbon dioxide made by respiration diffuses in the opposite direction to be carried by plasma, washed away from the cells..
Scene 6 (55s)
Deoxygenated blood returns to the heart via the venae cavae, to the right atrium, then the right ventricle, and leaves through the pulmonary veins, back to the lungs..
Scene 7 (1m 8s)
Carbon dioxide diffuses from the blood vessels to the alveoli..
Scene 8 (1m 16s)
Carbon dioxide then moves up the respiratory tract to be breathed out..