ACTIVE HYPEREMIA Meaning and
Definition
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Active hyperemia is a physiological condition characterized by an increased blood flow to a specific organ or tissue due to enhanced metabolic activity and demand for oxygen and nutrients. It refers to the dilation of blood vessels supplying a particular region in response to increased local metabolic demands of that region. This increased blood flow occurs as a result of the arterioles and capillaries in the affected area undergoing vasodilation.
The underlying mechanism driving active hyperemia involves the release of various vasoactive substances in response to metabolic changes. When an organ or tissue experiences heightened activity, a rise in metabolic byproducts such as adenosine, carbon dioxide, lactic acid, and potassium ions occurs. These byproducts act as local vasodilators, causing the smooth muscles in the walls of arterioles and capillaries to relax, leading to increased blood flow.
Active hyperemia plays a crucial role in ensuring proper oxygen delivery and nutrient supply to the tissues during increased metabolic demand. Examples of situations where active hyperemia occurs include exercise, digestion, and inflammation. In these instances, organs and tissues require an augmentation in blood flow to meet the increased metabolic demands associated with heightened activity.
Overall, the concept of active hyperemia is essential in understanding the regulation of blood flow and its adaptation to the metabolic needs of different organs and tissues in response to physiological demands.
Etymology of ACTIVE HYPEREMIA
The term "active hyperemia" is composed of two components: "active" and "hyperemia".
1. Active:
The word "active" originated from the Latin word "activus", which means "having the power to produce an effect". It entered the English language through the French word "actif" in the 14th century. "Active" refers to something being in motion, energetic, or involved in physical exertion.
2. Hyperemia:
The term "hyperemia" derives from the combination of the Greek words "hyper" meaning "excessive" and "haima" meaning "blood". It entered English usage in the mid-19th century. Hyperemia refers to an increased blood flow within a particular area of the body or an organ, resulting from the dilation of blood vessels.
Therefore, the etymology of "active hyperemia" suggests an excessive increase in blood flow caused by physiological or physical activity.
