• The lymphatic system has some organs associated with it and these are divided into primary organs which are sites where stem cells divide and become immune-competent that is capable of mounting an immune response and these include: the thymus and red bone marrow and the secondary organs which are sites where maturation occurs and most immune responses occur. These include the lymph nodes, spleen, lymphatic nodules and the tonsils.
• It is through these organs that lymph flows. Lymph is a fluid formed when some components of blood plasma filter through blood capillary walls to form interstitial fluid. It mainly consists of interstitial fluid, white blood cells and chyle which is a lipoprotein complex absorbed into lymph from digested foods in the gut. Lymph flows in one direction and is a clear pale- yellow fluid but appears creamy white in the small intestines because of the fatty acids.         
• Lymph vessels begin as lymphatic capillaries that unite to format larger lymphatic vessels that further unite to form trunks then ducts. Lymphatic capillaries are slightly larger than blood capillaries and have a special structure that permits interstitial fluid to flow into them but not out.
• This is so because the endothelial cells that make up the wall of the lymphatic capillary overlap in such a way that when pressure in the interstitial space is greater, the cells separate slightly to let in the interstitial fluid but when the pressure is greater in the lymphatic capillaries, the cells adhere more closely and thus lymph cannot escape back.

 The organization of some the organs of lymphatic system are discussed below;

• Lymph nodes: these are located along the lymphatic vessels and are scattered throughout the body both superficially and deep. They usually occur in groups and large groups of these are specially found in mammary glands, axilla and groin.
•  The lymph node has two sides that is the convex and the concave also known as hilum. The hilum is made up the vein, artery and efferent lymphatics and the convex is made of the afferent lymphatics. The lymph nodes have channels known as sinuses.
• The lymph node is organized in layers and these begin with the outermost capsule which radiates inward to form extensions known as trabeculae and the spaces between these trabeculae are known as the cortex. The central portion left is known as the medulla.
• The lymph thus travels through the lymph nodes from the afferent lymphatics then to the sub capsular sinuses to the trabecular sinuses that are adjacent to the trabeculae then onto the medullary sinuses the formed betwixt the channels left by the mesh like network by the medulla and from here the lymph is drained into the efferent vessel. The unidirectional movement here is maintained by the valves and the force to initiate the movement of the lymph across is from the reaction of the smooth muscles lining to arterial pulse and constant squeezing of skeletal muscles.         
• Tonsils: these include adenoids, tubal, palatine and inguinal. Together these form a ring of lymphoid tissue around the throat. They mostly serve to trap pathogens from the food we eat and the air we inhale.