What is the term used for the region of a lymph node through which blood vessels pass?

The term used for the region of a lymph node through which blood vessels pass is the hilum. The hilum is a specific anatomical feature of lymph nodes that serves as the entry and exit point for blood vessels, lymphatics, and nerves. This central area allows for the circulation of blood, which is crucial for the transport of immune cells and the overall functionality of the lymph node. It supports the immune response by facilitating the ingress of lymph and efferent blood supply that is essential for nutrient and waste exchange.

In contrast, the cortex is the outer region of the lymph node, primarily composed of lymphatic tissue where immune responses are initiated. The medulla is the inner area that contains medullary sinuses and cords, involved in filtering lymph. Follicles, or lymphoid follicles, are structures found within the cortex, rich in B cells, where antibody production occurs, but they do not serve as points for blood vessel passage.