easy efficient exchange between air and blood
Around the lungs,the blood is separated from the air inside each alveolus by only two cell layers; the cells making up the wall of the alveolus and the capillary wall itself. This is a distance of less than a thousandth of a millimetre. Because the air in the alveolus has a higer concentration of oxygen than the blood entering the capillary network, oxygen diffuses from the air across the wall of the alveolus and into the blood. That is why the distance is important.
→ layers from alveolus to capillary ①surfactant layer (inside alveolus) ②pneumocyteⅠ(typeⅠ cell) layer ③fused basal lamina (consists of basal laminae of alveolar epithelium and capillary endothelium) ④endothelium (inside capillary)
Diffusion (of anything) occurs because of a concentration gradient meaning there is more oxygen in one place than another. Alveolus when you inhale will have a higher concentration of oxygen that that of the alveolar capillary resulting in a concentration gradient, this causing diffusion to occur until equilibrium is met. This means more oxygen in alveolus so oxygen travels into the alveolar capillary until a balanced amount of oxygen is in both places, but then of course the oxygen is transported and you exhale and inhale so the process repeats.
The adjective for alveolus (singular) or alveoli (plural) is alveolar.
Yes gas is transferred through the alveolar/capillary membrane in the alveolus. Gas moves from the alveolar air sacs to the pulmonary capillaries.
Oxygen.
In the alveoli
carbon dioxide
The layers of the respiratory membrane include the alveolar epithelium, the basement membrane, and the capillary endothelium. These layers are involved in facilitating the exchange of gases, such as oxygen and carbon dioxide, between the air in the lungs and the blood in the capillaries.
An oxygen molecule must pass through four cell layers to move from an alveolus into the bloodstream: the alveolar epithelial cells, the capillary endothelial cells, and their basement membranes. This process is essential for oxygen exchange in the lungs.
Alveolus is a single structure in the lungs where gas exchange occurs, while alveolar sac is a cluster of alveoli where multiple gas exchange processes happen simultaneously. Alveolar sacs are made up of multiple alveoli grouped together.
Alveolar macrophage cells work to clear particles from the alveolus by phagocytosis. If this process is overcome by continued build up of particles then the alveolus becomes damaged. Once an alveolus is blocked there isn't much you can do.