Question

Lymph nodes function as meeting points between antigen-bearing dendritic cells arriving from the tissue and recirculating B and T lymphocytes. Whereas the

dendritic cells coming from the tissue enter the lymph node via the afferent lymphatic
vessels, the recirculating lymphocytes enter the lymph node:

A. Also from the lymph fluid draining the tissue
B. Directly from their primary lymphoid organ where they develop
C. From the blood by crossing the high endothelial venules
D. By being trapped in the lymphoid follicle by resident macrophages
E. By being carried there by dendritic cells

Answer 1

The correct answer is option c. Recirculating B and T lymphocytes enter lymph nodes from the blood by crossing high endothelial venules, where they can respond to antigens presented by dendritic cells.

Step-by-step explanation:

Lymph nodes are vital components of the lymphatic and immune systems. They function as filters, removing debris and pathogens from the lymph fluid, and are also key sites for adaptive immune responses. When dendritic cells carry antigen information from the tissue to the lymph nodes, they enter via the afferent lymphatic vessels.

In contrast, recirculating B and T lymphocytes enter the lymph nodes from the blood through structures known as high endothelial venules (HEVs). This process allows the immune cells to quickly respond to foreign antigens presented by the dendritic cells.