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Reinflation of the alveoli following exhalation is made easier by the surfactant, which reduces surface tension in the thin fluid lining of the alveoli. The fluid coating is produced by the body in order to facilitate the transfer of gases between blood and alveolar air, and the type II cells are typically found at the blood–air barrier. [19 ...
Alveoli are the spherical outcroppings of the respiratory bronchioles. Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells . [ 1 ] The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions.
In effect, the single arterial pCO 2 value averages out the different pCO 2 values in the different alveoli, and so makes the Bohr equation useable. The quantity of CO 2 exhaled from the healthy alveoli is diluted by the air in the conducting airways (anatomic dead space) and by gas from alveoli that are over-ventilated in relation to their ...
Macrophages in the alveoli are part of the immune system which engulf and digest any inhaled harmful agents. Hair in the nostrils plays a protective role, trapping particulate matter such as dust. [14] These hairs, called vibrissae, are thicker than body hair and effectively block larger particles from entering the respiratory tract.
Red arrows indicate secreted lamellar bodies, and green arrows indicate lamellar bodies in the cytoplasm. Scale bar = 200 nm. In cell biology, lamellar bodies (otherwise known as lamellar granules, membrane-coating granules (MCGs), keratinosomes or Odland bodies) are secretory organelles found in type II alveolar cells in the lungs, and in keratinocytes in the skin.
An increase in Pi causes extraalveolar blood vessels to reduce in caliber, in turn causing blood flow to decrease (extraalveolar blood vessels are those blood vessels outside alveoli). Intraalveolar blood vessels (pulmonary capillaries) are thin walled vessels adjacent to alveoli which are subject to the pressure changes described by zones 1-3.
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The main reason for exhalation is to rid the body of carbon dioxide, which is the waste product of gas exchange in humans. Air is brought into the lungs through inhalation. Diffusion in the alveoli allows for the exchange of O 2 into the pulmonary capillaries and the removal of CO 2 and other gases from the pulmonary capillaries to be exhaled ...