Search results
Results from the WOW.Com Content Network
The alveoli are tiny air sacs in the lungs where gas exchange takes place. The mean number of alveoli in a human lung is 480 million. [11] When the diaphragm contracts, a negative pressure is generated in the thorax and air rushes in to fill the cavity. When that happens, these sacs fill with air, making the lung expand.
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 ...
The tendency for the alveoli to collapse is therefore almost the same at the end of exhalation as at the end of inhalation. Thirdly, the surface tension of the curved watery layer lining the alveoli tends to draw water from the lung tissues into the alveoli. Surfactant reduces this danger to negligible levels, and keeps the alveoli dry. [6] [37]
Elastin is more concentrated in areas of high stress such as the openings of the alveoli, and alveolar junctions. [19] The connective tissue links all the alveoli to form the lung parenchyma which has a sponge-like appearance. The alveoli have interconnecting air passages in their walls known as the pores of Kohn. [20]
The process of breathing does not fill the alveoli with atmospheric air during each inhalation (about 350 ml per breath), but the inhaled air is carefully diluted and thoroughly mixed with a large volume of gas (about 2.5 liters in adult humans) known as the functional residual capacity which remains in the lungs after each exhalation, and ...
Almost any type of lung tumor or lung cancer can compress the alveoli and reduce gas exchange capacity. In some cases the tumor will fill the alveoli. [33] Cavitary pneumonia is a process in which the alveoli are destroyed and produce a cavity. As the alveoli are destroyed, the surface area for gas exchange to occur becomes reduced.
As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During forced exhalation , as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles generate abdominal and thoracic pressure, which ...
Real-time magnetic resonance imaging of the human thorax during breathing X-ray video of a female American alligator while breathing. Breathing (spiration [1] or ventilation) is the rhythmical process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.