OBJECTIVE LIFE SCIENCE
SIGNALLING IMMUNOLOGY CANCER
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Low epithelial venule
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high epithelial venule
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loose epithelial venule
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hard epithelial venule
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Detailed explanation-1: -Lymphocytes enter lymph nodes directly from the blood by migrating across the walls of specialized postcapillary venules which are located in the paracortex (T lymphocyte areas) of the node. These vessels have a characteristic morphology which distinguishes them from other types of blood vessel.
Detailed explanation-2: -High endothelial venules (HEV) are specialized post-capillary venules characterized by plump endothelial cells as opposed to the usual flatter endothelial cells found in regular venules. HEVs enable lymphocytes circulating in the blood to directly enter a lymph node (by crossing through the HEV).
Detailed explanation-3: -B cells home to the lymph nodes (LNs) via high endothelial venules (HEVs) under the guidance of chemokines, particularly CXCL13. However, as CXCL13 is not directly made in HEVs, the molecular mechanism mediating B-cell homing to LNs has remained unclear.