Search results
Results From The WOW.Com Content Network
Diffusion occurs through the walls of the vessels due to a concentration gradient, allowing the necessary exchange of ions, molecules, or blood cells. The permeability of a capillary wall is determined by the type of capillary and the surface of the endothelial cells. A continuous, tightly spaced endothelial cell lining only permits the ...
The term capillary exchange refers to all exchanges at microcirculatory level, most of which occurs in the capillaries. Sites where material exchange occurs between the blood and tissues are the capillaries, which branch out to increase the swap area, minimize the diffusion distance as well as maximize the surface area and the exchange time. [4]
The interchange of materials between cells and fluid, which happens via diffusion or active transport, is considerably accelerated because tissue fluid-carrying dissolved nutrients are in direct touch with tissue cells. Tissue fluid is generally reabsorbed into capillaries after the exchange, which eventually empties into venules
There are two types of capillaries: true capillaries, which branch from arterioles and provide exchange between tissue and the capillary blood, and sinusoids, a type of open-pore capillary found in the liver, bone marrow, anterior pituitary gland, and brain circumventricular organs. Capillaries and sinusoids are short vessels that directly ...
Animation of a typical human red blood cell cycle in the circulatory system. This animation occurs at a faster rate (~20 seconds of the average 60-second cycle ) and shows the red blood cell deforming as it enters capillaries, as well as the bars changing color as the cell alternates in states of oxygenation along the circulatory system.
In intercellular clefts of capillaries, it has been calculated that the fractional area of the capillary wall occupied by the intercellular cleft is 20m/cm 2 x 20 nm (length x width)= 0.004 (0.4%). This is the fractional area of the capillary wall exposed for free diffusion of small hydrophilic solutes and fluids 5.
The rate at which fluid is filtered across vascular endothelium (transendothelial filtration) is determined by the sum of two outward forces, capillary pressure and colloid osmotic pressure beneath the endothelial glycocalyx (), and two absorptive forces, plasma protein osmotic pressure and interstitial pressure (). The Starling equation is the ...
Upon entering the lumen of a lymphatic capillary, the collected fluid is known as lymph. Each lymphatic capillary carries lymph into a lymphatic vessel, which in turn connects to a lymph node, a small bean-shaped gland that filters and monitors the lymphatic fluid for infections. [1] Lymph is ultimately returned to the venous circulation.