Lymph Node Medullary Portion

**Semantic type:** Tissue

**Definition:** The central portion of the lymph node. It is divided into sections by tracts of lymphatic tissue called medullary cords. Between the medullary cords are the medullary sinuses, which consist mainly of macrophages that engulf microorganisms as part of the lymph node's filtering function. Lymphocytes and plasma cells are also found in the medullary portion.