LYMPH NODE
Figure 10­6
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Lymph nodes are small, encapsulated, kidney-shaped structures inserted within the pathway of lymphatic vessels.
Their connective tissue capsule is penetrated by afferent lymphatic vessels that carry lymph to the organ. Lymph
nodes are the only structures in the body that have both afferent and efferent lymphatic vessels. The lymph flows
LLC.
through the sinuses in the organ and is drained by the efferent channels leading from the hilar indentation. At the
Not
hilus, blood vessels enter and leave the structure.
to
be
Lymph nodes function in the filtration of lymph by the phagocytic activity of macrophages in the organ. Lymph nodes
redistributed
are important structures in the immune mechanisms of the body. The cells in the nodes respond to antigenic stimu-
lation and the nodes are the sites for the proliferation, maturation, and storage of both T- and B-lymphocytes.
As shown in this low-magnification micrograph, lymph nodes have an outer cortex (C) of aggregations of lympho-
or
modified
cytes and an inner medulla (M) consisting of cords of lymphoid tissue and sinuses carrying the lymph fluid. The hilus
is not shown in this micrograph.
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