Hyperaemia

Source: Wikipedia, the free encyclopedia.
Hyperemia
Other namesHyperæmia, hyperemia

Hyperaemia (also hyperemia) is the increase of

oxygenated blood.[1] Hyperaemia can also occur due to a fall in atmospheric pressure outside the body. The term comes from Greek
ὑπέρ (hupér) 'over', and αἷμα (haîma) 'blood'.

Regulation of blood flow

Functional hyperaemia is an increase in blood flow to a tissue due to the presence of

extracellular concentration of such chemicals as adenosine, carbon dioxide, and lactic acid, and a decrease in oxygen and pH. These changes cause significant vasodilation. The reverse occurs when metabolic activity is slowed and these substances wash out of the tissues. The myogenic effect refers to the inherent attempt of vascular smooth muscle surrounding arterioles and arteries to maintain the tension in the wall of these blood vessels by dilating when internal pressure is reduced and to constrict when wall tension increases.[2]

Functional hyperaemia

Functional hyperaemia, metabolic hyperaemia, arterial hyperaemia or active hyperaemia, is the increased blood flow that occurs when tissue is active.[3]

Hyperaemia is likely mediated by the increased synthesis and/or release of vasodilatory agents during periods of heightened cellular metabolism. The increase in cellular metabolism causes the increase in vasoactive metabolic byproducts. Some of the putative vasodilatory agents (associated with metabolism) include, but are not limited to: carbon dioxide (CO2), hydrogen ion (H+), potassium (K+),

endothelial cells may be coordinators of skeletal muscle blood flow during functional hyperaemia. It is thought that vasodilators (released from active muscle fibers) can stimulate a local capillary endothelial cells which, in turn, causes the conduction of a vasodilatory signal to upstream arterioles, this then elicits arteriolar vasodilation consequently, creating a pathway of least resistance so blood flow can be precisely direct to capillaries supplying the metabolically active tissue.[5]

Conversely, when a tissue is less metabolically active, it produces fewer metabolites which are simply washed away in blood flow.[citation needed]

Since most of the common nutrients in the body are converted to

interstitial fluid. The relaxation of this smooth muscle results in vascular dilation and increased blood flow.[citation needed
]

Some tissues require oxygen and fuel more quickly or in greater quantities. Examples of tissues and

organs that are known to have specialized mechanisms for functional hyperaemia include:[citation needed
]

Reactive hyperaemia

Reactive hyperemia, classified under arterial hyperemia, refers to the temporary increase in blood flow to an organ that follows a short period of ischemia or ischaemia. This condition arises due to a shortage of oxygen and an accumulation of metabolic waste resulting from the ischemic episode. A common method to assess this condition, particularly in the legs, is through Buerger's test. Furthermore, reactive hyperemia is frequently associated with Raynaud's phenomenon. In this scenario, vasospasm within the blood vessels leads to ischemia, which can cause tissue necrosis. Subsequently, there is an increased blood flow to the affected area, aimed at eliminating waste products and clearing cellular debris.[6]

References

  1. ISBN 978-1-4160-3121-5
    .
  2. ISSN 0031-9333
    .
  3. ISSN 1043-4046
    .
  4. PMID 26426256
    .
  5. S2CID 3706150
    .
  6. ^ "CV Physiology | Reactive Hyperemia". cvphysiology.com. Retrieved 2023-12-14.

External links


Retrieved from "https://en.wikipedia.org/w/index.php?title=Hyperaemia&oldid=1199047185"