Search results
Results From The WOW.Com Content Network
The alveolar gas equation is the method for calculating partial pressure of alveolar oxygen (p A O 2). The equation is used in assessing if the lungs are properly transferring oxygen into the blood. The alveolar air equation is not widely used in clinical medicine, probably because of the complicated appearance of its classic forms.
The alveolar oxygen partial pressure is lower than the atmospheric O 2 partial pressure for two reasons. Firstly, as the air enters the lungs, it is humidified by the upper airway and thus the partial pressure of water vapour (47 mmHg) reduces the oxygen partial pressure to about 150 mmHg.
Breathing (spiration [1] or ventilation) is the rhythmical process of moving air into ... alveolar ducts and alveoli are specialized for gas exchange. [8] [11]
Collateral ventilation is a back-up system of alveolar ventilation that can bypass the normal route of airflow when airways are restricted or obstructed. The pathways involved include those between adjacent alveoli ( pores of Kohn ), between bronchioles and alveoli (canals of Lambert), and those between bronchioles (channels of Martin).
The ventilation/perfusion ratio (V/Q ratio) is higher in zone #1 (the apex of lung) when a person is standing than it is in zone #3 (the base of lung) because perfusion is nearly absent. However, ventilation and perfusion are highest in base of the lung, resulting in a comparatively lower V/Q ratio.
Total dead space (also known as physiological dead space) is the sum of the anatomical dead space and the alveolar dead space. Benefits do accrue to a seemingly wasteful design for ventilation that includes dead space. [1] Carbon dioxide is retained, making a bicarbonate-buffered blood and interstitium possible.
Ventilation is wasted, as it fails to oxygenate any blood. A high V/Q can also be observed in emphysema as a maladaptive ventilatory overwork of the undamaged lung parenchyma. Because of the loss of alveolar surface area, there is proportionally more ventilation per available perfusion area.
There are three major types of alveolar cell. Two types are pneumocytes or pneumonocytes known as type I and type II cells found in the alveolar wall, and a large phagocytic cell known as an alveolar macrophage that moves about in the lumens of the alveoli, and in the connective tissue between them. Type I cells, also called type I pneumocytes ...