OVERVIEW OF THE IMMUNE SYSTEM
LYMPHATIC AND IMMUNE SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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form tight junctions
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overlap creating micro-valves
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are fenestrated to promot fluid movement
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None of the above
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Detailed explanation-1: -Lymphatic Vessels The wall of the lymph capillary is composed of endothelium in which the simple squamous cells overlap to form a simple one-way valve. This arrangement permits fluid to enter the capillary but prevents lymph from leaving the vessel.
Detailed explanation-2: -Yes, lymphatic capillaries have overlapping endothelial cells. By overlapping the cells, they are able to create valves along the capillary. The valves permit interstitial fluid to enter and move along the capillary but not to flow in reverse.
Detailed explanation-3: -These bulbous sacs (10–60 m diameter) are called initial, or terminal, lymphatics. Initial lymphatics possess overlapping endothelial cells that behave collectively like a valve, only permitting unidirectional entry of fluid, solute, and cells into the lumen of these vessels (Figure 3.1).
Detailed explanation-4: -Fluid enters lymphatic capillaries when rising pressure caused by the build-up of interstitial fluid pushes open a flap where adjacent endothelial cells of a lymphatic capillary overlap. The interstitial fluid is then called lymph and it drains into larger lymphatic vessels.