capillary permeability


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capillary permeability

Etymology: L, capillaris, hairlike, permeare, to pass through
a condition of the capillary wall structure that allows blood elements and waste products to pass through the capillary wall to tissue spaces.

capillary permeability

The condition of the capillary wall that enables substances in the blood to pass into tissue spaces or into cells, or vice versa.
See also: permeability

capillary

1. pertaining to or resembling a hair.
2. one of the minute vessels connecting arterioles and venules, the walls of which act as a membrane for interchange of various substances between the blood and tissue fluid. (See circulatory system.) The walls consist of thin endothelial cells through which dissolved substances and fluids can pass. At the arterial end, the blood pressure within the capillary is generally higher than the pressure in the surrounding tissues, and the blood fluid and some dissolved solid substances pass outward through the capillary wall. At the venous end of the capillary, the pressure within the tissues is generally higher, and waste material and fluids from the tissues pass into the capillary, to be carried away for disposal. See starling's hypothesis.

continuous capillary
a capillary with no pores or other interruptions in the endothelial walls, e.g. in muscle, lung, nervous system.
fenestrated c's
capillaries with pores are scattered throughout the endothelial walls, e.g. in endocrine glands, intestines, kidneys.
capillary fragility
see capillary fragility.
lymph capillary
the smallest lymphatic vessel. Consists of an endothelial tube embedded in connective tissue.
perforated capillary
see fenestrated capillary (above).
capillary permeability
ability of large molecules to pass out of the capillary lumen into surrounding tissue spaces; inflammation, allergy, poisoning, burns cause increased permeability resulting in plasma leakage and edema in surrounding tissues.
capillary refill time (CRT)
the time required for mucosa (oral in horse or dog, vaginal in cow, sheep) which has been blanched by finger pressure to return to a normal pink color. Failure to return promptly is an indication of peripheral circulatory failure, due for example to dehydration or hypovolemic shock.
sinus c's
part of the vasculature of avian skin. Occur together with standard capillaries but they are larger in diameter and may have some smooth muscle cells associated with the endothelial cells.
sinusoidal c's
large and irregularly shaped; occur in endocrine glands, aortic and carotid bodies.
References in periodicals archive ?
Intradermal injection of venom enzyme, without an exogenous source of kininogen, did not produce an increase in capillary permeability.
An increase in capillary permeability was not seen following direct intradermal injection of either the venom enzyme or plasma kallikrein.
Maldistribution due to venodilatation and hypovolaemia secondary to increased capillary permeability and plasma extravasation contribute to circulatory shock.
Loss of circulating volume in anaphylaxis is due to a combination of increased capillary permeability with fluid extravasation into the interstitial space and sequestration in grossly dilated vascular beds leading to a profound reduction in venous return.
In addition, escin decreases capillary permeability.
Pulmonary edema occurs for a number of reasons, including a redistribution of bodily fluid that changes capillary permeability and increases pulmonary blood volume.
Increased extravascular lung water occurs in association with pulmonary oedema from increased pulmonary capillary permeability (acute lung injury or acute respiratory distress syndrome) or from an increase in pulmonary capillary pressure (hydrostatic or cardiogenic pulmonary oedema).
1,2) Factors such as changes in capillary hydrostatic pressure, capillary blockage and inflammation resulting in increased capillary permeability may also be involved, but are more commonly encountered with localised forms of oedema.
SCLS is a disease characterized by spontaneous recurrent episodes of hypovolaemic shock due to extravasation of plasma resulting from altered capillary permeability.