Lymphatic system:

• The lymphatic system consists of the lymphatic fluid (called lymph), the lymphatic vessels which move the lymph, and the lymphatic structures and organs

• This system has several functions. It drains protein-containing fluids from the areas between cells, leakage from the cappilaries, and are returned to the circulatory system.  Lymphocytes, with the aid of macrophages, protect the body from foreign cells. Lymphocytes are often called T and B cells

• Lymphatic tissues are reticular connective tissue containing large numbers of lymphocytes

• Unencapsulated groupings of lymphatic tissues are referred to as diffuse lymphatic tissue. This is the simplest form of lymphatic tissue, found in the lamina propria of mucous membranes on the GI tract, respiratory tract, urinary and reproductive tracts

• Lymphatic nodules are also unencapsulated, arranged in an oval shape. They are located in seemingly random area of the lamina propria of mucous membranes. They are most apparent as the Peyer's patches, or aggregated lymphatic follicles in the ileum and small intestine in larger aggregations

• Lymphatic organs include the lymph nodes, spleen and the thymus. All are enclosed by a connective tissue capsule

• Bone marrow is also considered a part of the lymphatic system, since it produces the needed lymphocytes