ANATOMY

Detailed explanation-1: -Tiny air sacs at the end of the bronchioles (tiny branches of air tubes in the lungs). The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.

Detailed explanation-2: -Diffusion is the spontaneous movement of gases, without the use of any energy or effort by the body, between the alveoli and the capillaries in the lungs.

Detailed explanation-3: -Lungs are divided into sacs to increase the surface area and to easily transport oxygen to the blood vessels which surrounds the air sacs and also air sacs have a thin film of oxygen which helps to absorb oxygen quickly.

Detailed explanation-4: -An alveolus consists of an epithelial layer of simple squamous epithelium (very thin, flattened cells), and an extracellular matrix surrounded by capillaries. The epithelial lining is part of the alveolar membrane, also known as the respiratory membrane, that allows the exchange of gases.

Detailed explanation-5: -Gas exchange in the alveoli occurs primarily by diffusion. Traveling from the alveoli to capillary blood, gases must pass through alveolar surfactant, alveolar epithelium, basement membrane, and capillary endothelium.