Also called a lymph gland, this is a round or oval mass of
lymphatic tissue found on a lymphatic vessel within the lymphatic system. These masses filter lymphatic fluid, which is collected and transported by the lymphatic system from around the tissues to the blood circulatory system.
Germinal centers are areas within lymph nodes where
B lymphocytes rapidly divide.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.