Surfactant is a complex substance containing phospholipids and a number of apoproteins. This essential fluid is produced by the Type II alveolar cells, and lines the alveoli and smallest bronchioles. Surfactant reduces surface tension throughout the lung, thereby contributing to its general compliance. It is also important because it stabilizes the alveoli.
Stagnant anoxia occurs when there is interference with the blood flow, although the blood and its oxygen-carrying abilities are normal. A common cause of general stagnant anoxia is heart disease or interference with the return of blood flow through the veins.
Anoxia can result from inadequate amounts of oxygen in the air, such as at high altitudes, from an inability of your blood to load and carry oxygen to tissues and organs, from the inability of the heart to pump and distribute the oxygenated blood adequately, or from respiratory failure that prevents the blood from picking up oxygen in the lungs.