Term
| What is the diameter of a RBC and capillary? |
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Definition
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Term
| What cell type are endothelial cells and what specialized organelles do they contain? |
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Definition
-They are flat polygonal
-They have Weibel-Palse bodies which store von Willebrand factor |
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Term
| What is a marginal fold in endothelium? |
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Definition
| -When opposing corners of the squamous cells of capillaries overlap with one end protruding into the lumen |
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Term
| What is the name for the internal and external surfaces of the endothelium? |
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Definition
-luminal and abluminal surfaces
-abluminal surface makes the basement membrane |
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Term
| What are the three layers of the basement membrane? |
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Definition
| -Lamina lucida, densa, and fibroreticularis |
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Term
| What are pericytes? Other name? |
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Definition
-Pericytes, or Rouget cells, clasp the capillary walls and function in wound healing by becoming fibroblasts
-Fibroblasts make scar tissue and smooth muscle |
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Term
| Where do we find continuous thick capillaries? How thick are the cells? |
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Definition
-In muscle tissue and parts of ovaries and testes
-The endothelial cells are 200nm thick and are united by desmosomes and gap junctions
-They use micropinocytotic vesicles for transport
-Surrounded by complete basement membrane |
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Term
| What is the function of thin continuous capillaries? What are two distinguishing features of them? |
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Definition
-serves as blood-tissue barrier selecting only certain sized molecules to enter or exit capillaries
-They have zona occludens (tight junctions)
-Absence of micropinocytosis vesicles
-They are 100nm thick |
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Term
| Give three examples of blood-tissue barriers? |
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Definition
| -Blood-brain, blood-thymus, blood-ganglion |
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Term
| Where do we find fenestrated capillaries with diaphragms and what is the purpose? |
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Definition
-They are for rapid fluid exchange
-Choroid plexus, ciliary body, kidney peritubular plexus |
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Term
| -Where do we find fenestrated capillaries without diaphragms? |
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Definition
-In renal glomeruli
-Have very thick basement membranes |
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Term
| What are sinusoids and where can we find them? |
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Definition
-They are modified to retain large quantities of blood under low pressure
-Have sparse or absent basement membranes
-Can find them in the liver, bone marrow, in sympathetic ganglia, and elsewhere
-They have fenestrae are open and variable sized |
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