Edema Flashcards
Edema
A condition characterized by an excess of watery fluid collecting in the cavities or tissues of the body.
- Is a natural response following an acute injury as it is part of the inflammatory phase of wound healing.
- Normal part of inflammatory stage- we want this to occur.
Effects of edema
Swelling, Pain- compresses on tissue, Loss of motion and function, Compression on nerves and blood vessels, Fibrosis, Increased scarring of the skin if a laceration injury.
Fibrosis
The thickening of connective tissue, usually as a result of injury. It is different than scar tissue. IT is a physical, mechanical change of the soft tissues that affects all tissue including blood vessels, lymphatics, muscles, ligaments, tendons and skin.
-Becomes hardened, thick, and foggy, and can calcify into scar tissue. Tissue becomes hard and is no longer soft and does not glide well.
causes of edema
Trauma Infection Venous insufficiency Lymphatic Dysfunction Cancer Arterial occlusion (cool, pale, LE) venous obstruction pressure poor circulation
Physiology of Edema
- Body fluid regulation between interstitial fluid and blood plasma
- Arterial system brings oxygen and nutrients to the cells
- Venous system removes waste and carbon dioxide
- Lymphatic system removes waste in the form of plasma proteins from interstitial fluid.
*Lymphatic system- responsible for taking out the trash. Usually formed of plasma proteins.
Role of histamine
- Part of an immune response to foreign pathogens is the release of histamine
- Histamine is found in nearby connective tissues
- Histamine increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engage pathogens in the infected tissues (opens the gates)
- Normally a good guy but can be a bad guy when it shows up when not invited
- causes vasodilation (lets trash into capillaries so that our blood can get rid of some of the small garbage.
Histamine
- Vasodilation and a fall in blood pressure
- Increased vascular permeability causes fluid to escape from capillaries into the tissues, which leads to the classic symptoms of an allergic reaction. A runny nose and watery eyes. (allergies) histamine response to our allergies.
- High amounts of histamine can increase edema
- foods can increase histamine (wine and cheese)
- also mosquitos do too.
edema physiology
1) there is a constant fluid exchange between tissue and plasma across the capillary membrane
2) the fluid enters and exits through gates along the capillary wall.
3) The molecules that make up this fluid vary in size.
4) For this reason fluid in the tissue can vary in consistency from thick to thin.
5) Protein molecules are large and have difficulty getting through the capillary gate.
Have to use lymphatic system to get ride of larger molecules such as proteins. smaller molecules can pass through capillaries.
Hydrostatic pressure
- the fact that blood is pumped under pressure.
- The capillary wall is semipermeable. Think about turning on a garden hose that has small holes in it.
-capillaries are one cell thick and so it is not much of a barrier when the pressure inside is higher than outside. The blood pressure forces fluid out of capillaries.
the pressure our heart generates when it beats.
Hydrostatic pressure continued
Definition: the force that is exerted by a fluid against the capillary wall.
- It helps in the movement of fluid between capillaries and the interstitial fluid.
- Highest pressure on arterial side and lowest pressure on the venous end.
Osmotic Pressure
The minimum pressure applies to a solution to prevent the inward flow of water across a semipermeable membrane.
-more water wants to travel to areas of less water. Wants to balance things out but osmotic pressure applies the minimum amount of pressure to prevent that from happening
blood vessel tendency
Blood tends to be slightly more hypertonic than the surrounding interstitial fluid.
- This tends to keep the water inside the blood vessel.
- this is good because it helps eliminate waste in the body.
-OSMOTIC pressure tends to push into the bloodstream.
opposing forces
-Hydrostatic pressure and osmotic pressure are working against each other. Blood pressure is forcing water out and the osmotic pressure forces are trying to keep blood in.
- the two forces do not quite cancel each other out.
- hydrostatic pressure wins. capillaries leak, but just a little.
-hydrostatic pushes stuff out and osmotic pushes stuff in.
Osmotic pressure
is 25 mm hg.
-it controls the movement in and out of the gates.
Capillary Hydrostatic pressure .
-is higher at the arterial end at 35 mm hg and around 15 mm hg at venous end
