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How do blood cells pass through a capillary?

  1. Apr 20, 2010 #1
    Hello guys,

    A capillary is made up of a single layer of endothelial cells right. So when blood cells pass through it, do the endothelial cells take blood cells up by endocytosis and then release it to other side.

    How do capillaries take up nutrients, do the endothelial cells take it up intracellularly and then pass it or do they fit into the gap of endothelial cells?

    Thanks :smile:
     
    Last edited: Apr 20, 2010
  2. jcsd
  3. Apr 21, 2010 #2
    Capillaries are small tubes, constructed of a sheet comprised of a single layer of endothelial cells wrapped around a small tubular channel through which the blood passes. Therefore the blood cells do not need to be endocytosed to move through a capillary, they just travel along though the center of the tube.

    Some small molecules can diffuse out of the blood between the endothelial cells, though in healthy cells the junctions between the endothelial cells are pretty tight and such diffusion is very limited. In tumors they are more leaky. Materials may be endocytosed through the endothelial cells and passed into the extracellular space outside the capillary. During a cellular immune response, white blood cells may open space between the capillary endothelial cells and force their way out of the blood and into the extracellular space.
     
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