Search results
Results from the WOW.Com Content Network
Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.
The anatomy of the airways means inspired air must pass through the mouth, trachea, bronchi and bronchioles (anatomical dead space) before it gets to the alveoli where gas exchange will occur; on exhalation, alveolar gas must return along the same path, and so the exhaled sample will be purely alveolar only after a 500 to 1,000 ml of gas has ...
Recall that the relationship represented in a Davenport diagram is a relationship between three variables: P CO 2, bicarbonate concentration and pH.Thus, Fig. 7 can be thought of as a topographical map—that is, a two-dimensional representation of a three-dimensional surface—where each isopleth indicates a different partial pressure or “altitude.”
Gas exchange takes place in the gills which consist of thin or very flat filaments and lammellae which expose a very large surface area of highly vascularized tissue to the water. Other animals, such as insects , have respiratory systems with very simple anatomical features, and in amphibians , even the skin plays a vital role in gas exchange.
The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...
Dead space reduces the amount of fresh breathing gas which reaches the alveoli during each breath. This reduces the oxygen available for gas exchange, and the amount of carbon dioxide that can be removed. The buildup of carbon dioxide is usually the more noticeable effect unless the breathing gas is hypoxic as occurs at high altitude.
Terminal bronchioles mark the end of the conducting division of air flow in the respiratory system while respiratory bronchioles are the beginning of the respiratory division where gas exchange takes place. The diameter of the bronchioles plays an important role in air flow. The bronchioles change diameter to either increase or reduce air flow.
The partial pressure of oxygen (pO 2) in the pulmonary alveoli is required to calculate both the alveolar-arterial gradient of oxygen and the amount of right-to-left cardiac shunt, which are both clinically useful quantities. However, it is not practical to take a sample of gas from the alveoli in order to directly measure the partial pressure ...