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FIG 5. Classification of the true capillary.
A, Brain type of continuous capillary. In morphologic features, the blood-brain (nerve) barrier of endothelial blood vessels consists of tight junction (zonulae occudentes) between adjacent endothelial cells and a very small number of pinocytotic vesicles. This capillary is mainly located in the central and peripheral nerve.
B, Muscle type of continuous capillary. In morphologic features, their endothelial cells are linked with tight junction; however, pinocytotic vesicles related to transport of nutrients and waste matter are much more abundant in endothelial cells of a capillary on muscle than capillary of brain type.
C, Fenestrated capillary. This capillary has a fenestration with a diaphragm in an endothelial cell and is mainly located in stomach, colon, and kidney.
D, Discontinuous capillary (sinusoid). Between the endothelial cells are large gaps, which permit a direct continuity of access of blood plasma from the lumen to the extracellular space. This capillary is mainly located in liver, spleen, hypophysis cerebre, and bone marrow. Et, vascular endothelium.
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