Functional hyperemia

Functional hyperemia

Functional hyperemia, or active hyperemia, is the increased blood flow that occurs when tissue is active.

When cells within the body are active in one way or another, they use more oxygen and fuel, such as glucose or fatty acids, than when they are not. The blood vessels compensate for this metabolism by dilatation, allowing more blood to reach the tissue. This prevents deprivation of the tissue.

Since most of the common nutrients in the body are converted to carbon dioxide when they are metabolized, smooth muscle around blood vessels relax in response to increased concentrations of carbon dioxide within the blood and surrounding interstitial fluid. The relaxation of this smooth muscle results in vascular dilation and increased blood flow.

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 hyperemia include:

* The brain through the neuron-dependent hemodynamic response.
* Penile erection tissue by release of nitric oxide.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • hyperemia —    Excessive presence of blood, usually arterial; and the resultant increase in heat and metabolic rate. Hyperemia can be a pathology, blowing out blood vessels and the like; used here to describe the chronic or subclinical condition of… …   Herbal-medical glossary

  • Hyperaemia — Infobox Disease Name = PAGENAME Caption = DiseasesDB = 4466 ICD10 = ICD9 = ICD9|780.99 ICDO = OMIM = MedlinePlus = eMedicineSubj = eMedicineTopic = MeshID = D006940 Hyperemia describes the increase of blood flow to different tissues in the body.… …   Wikipedia

  • congestion — Presence of an abnormal amount of fluid in the vessels or passages of a part or organ; especially, of blood due either to increased influx or to an obstruction to outflow. SEE ALSO: hyperemia. [L. congestio, a bringing together, a heap, fr. con… …   Medical dictionary

  • syndrome — The aggregate of symptoms and signs associated with any morbid process, and constituting together the picture of the disease. SEE ALSO: disease. [G. s., a running together, tumultuous concourse; (in med.) a concurrence of symptoms, fr. syn,… …   Medical dictionary

  • Osteonecrosis of the jaw — Osteonecrosis of the jaws Classification and external resources Osteonecrosis of the jaw of the upper left jaw in a patient diagnosed with chronic venous insufficiency ICD 10 M …   Wikipedia

  • animal disease — ▪ non human Introduction       an impairment of the normal state of an animal that interrupts or modifies its vital functions.       Concern with diseases that afflict animals dates from the earliest human contacts with animals and is reflected… …   Universalium

  • Myocardial infarction — Heart attack redirects here. For other uses, see Heart attack (disambiguation). Myocardial infarction Classification and external resources Diagram of a myocardial infarction (2) of the tip of the anterior wall of the heart (an apical infarct)… …   Wikipedia

  • Diverticulitis — Classification and external resources Large bowel (sigmoid colon) showing multiple diverticula. The diverticula appear on either side of the longitudinal muscle bundle (taenium). ICD 10 …   Wikipedia

  • Gastrointestinal bleeding — A positive fecal occult blood test ICD 10 K92.2 ICD 9 …   Wikipedia

  • Avascular necrosis — Classification and external resources Femur head showing a flap of cartilage (osteochondritis dissecans) due to avascular necrosis. Specimen from total hip replacement surgery …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”