Hemodynamics

from Wikipedia, the free encyclopedia

The hemodynamics describes the blood flow in the blood vessels in response to the responsible staff.

Various parameters are decisive for the fluid mechanics of the blood:

  • the geometry of the vessel
  • the elasticity of the vessel
  • the pressures in it
  • the cardiac output (locally as flow velocity)
  • the blood volume
  • the blood composition

Recent studies show that hemodynamics are not only important for the flow of blood per se, but that hemodynamic forces have a significant influence on the physiology of the endothelium and the smooth vascular muscles. The endothelial cells are able to perceive changes in blood pressure and shear stress and, depending on this, control the vascular muscles to regulate these parameters. An increase in the shear stress leads to the release of vasodilatory substances which, by widening the vessel lumen, reduce blood pressure and the flow rate again. Another effect is the release of a growth factor for the smooth vascular muscle cells, which guarantee the mechanical stability of the larger and medium-sized blood vessels. These mechanisms are an auto-regulation of blood flow.

In addition, however, the hemodynamics are essential for the survival of the vessel. If the hemodynamic stimuli cease to exist or if the laminar blood flow becomes discontinuous, the endothelium of the affected vessel reacts with apoptosis , which ultimately leads to the breakdown of the entire vessel. So that a brief flow disturbance does not lead to a complete breakdown of the endothelium via apoptosis, this process only starts with a few cells and only leads to a complete breakdown of the blood vessels if the disturbed state persists for a longer period of time.

See also

Web links