Edema Mechanism

The fluid levels in the body are tightly regulated through homeostatic mechanisms involving the kidneys and other parts of the body.

The production of interstitial fluid is regulated by the Starling equation forces. Hydrostatic pressure building up within the blood vessels causes water to flow out of the blood vessels and into the surrounding tissue. This increases the concentration of protein in the plasma, which causes more fluid to be drawn back into the vessels from the tissue.

According to the Starling equation, the rate at which fluid flows to and from the blood vessel walls depends on two important factors – the filtering forces and the permeability of the vessel wall to water.

The majority of leakage occurs in the capillaries or post capillary venules, which have membranes that are semipermeable and therefore allow water to pass more easily than protein. Gaps between the cells of the vessel wall open up and the permeability to water is increased. As the gaps increase in size, however, the membrane also becomes permeable to protein. If the forces in the Starling equation are altered, edema is more likely to occur.

Factors that contribute to the development of edema include:

  • An increase in the hydrostatic pressure
  • A decrease in the blood vessel oncotic pressure
  • An increase in tissue oncotic pressure
  • An increase in vessel wall permeability.
  • Obstructed lymphatic drainage
  • Water retention in tissues. For example, increased hydrostatic pressure often indicates sodium and water retention in the kidney.

Further Reading

Last Updated: Feb 26, 2019

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Mandal, Ananya. (2019, February 26). Edema Mechanism. News-Medical. Retrieved on October 17, 2019 from https://www.news-medical.net/health/Edema-Mechanism.aspx.

  • MLA

    Mandal, Ananya. "Edema Mechanism". News-Medical. 17 October 2019. <https://www.news-medical.net/health/Edema-Mechanism.aspx>.

  • Chicago

    Mandal, Ananya. "Edema Mechanism". News-Medical. https://www.news-medical.net/health/Edema-Mechanism.aspx. (accessed October 17, 2019).

  • Harvard

    Mandal, Ananya. 2019. Edema Mechanism. News-Medical, viewed 17 October 2019, https://www.news-medical.net/health/Edema-Mechanism.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.
Post a new comment
Post
You might also like... ×
Retinal macular damage linked to sleep apnea in diabetes