Altitude, acclimatization to: The process of adapting to the decrease in oxygen concentration at a specific altitude. A number of changes must take place for the body to operate with decreased oxygen. These changes include increasing the depth of respiration; increasing the pressure in the pulmonary arteries, forcing blood into portions of the lung that are normally not used at sea level; manufacturing additional oxygen-carrying red blood cells; and manufacturing extra2,4-DPG, a substance that facilitates the release of oxygen from hemoglobin to the body tissues. Acclimatization generally takes 1 to3 days and occurs after any significant altitude change above 1,220 meters (approximately4,000 feet). Acclimatization is the body’s natural means of correcting altitude sickness and the rate of acclimatization depends on the altitude, rate of ascent, and individual susceptibility.
- Altitude, high
Altitude, high: Altitude sickness occurs at high altitude. So what is high altitude? Altitude is defined on the following scale: High altitude: 8,000 – 12,000 feet (2,438 – 3,658 meters); Very high altitude: 12,000 – 18,000 feet (3,658 – 5,487 meters); and Extremely high altitude: 18,000+ feet (5,500+ meters). Most people can go up to […]
Aluminum: A naturally occurring element that makes up about 8% of the surface of the earth and is always found combined with other elements such as oxygen, silicon, and fluorine. Aluminum is the most common metallic element in the earth’s crust but has no clear biologic role. Everyone is exposed to low levels of aluminum […]
Alveolar: Pertaining to the alveoli, the tiny air sacs in the lungs. The exchange of oxygen and carbon dioxide takes place in the alveoli which look like cells in a honeycomb. The word comes from the Latin diminutive of “alveus” meaning a cavity or hollow = a little cavity or hollow.
- Alveolar hydatid disease
Alveolar hydatid disease: Abbreviated AHD. A parasitic disease caused by the larval stage of a microscopic tapeworm Echinococcus multilocularis. AHD is found worldwide, mostly in northern latitudes. in central Europe, Russia, China, Central Asia, Japan, and North America. In North America E. multilocularis is found primarily in the north central region from eastern Montana to […]
Alveoli: The plural of alveolus. The alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place.