Term | Definition |
Lymphatic system and function | Composed of lymphatic vessels and lymphatic organs. Functions: fluid balance, fat absorption, and defense (immune system) |
Lymphatic vessels/capillaries | Lymphatic tissue that absorbs excess tissue fluid. |
Lymph | The excess fluid that is absorbed by lymphatic vessels. |
Ducts of lymphatic vessels | Thoracic duct and right lymphatic duct. Theses ducts return tissue fluid back into the body. |
Edema | Swelling in lymphatic vessels as a result of the failure of the body to return tissue fluid back into the blood stream. |
Immunity | The ability to react to antigens so that the body remains free of disease. |
Lymphatic organs (Primary) | These organs contain large number of lymphocytes (white blood cells). The primary organs are red bone marrow and the thymus gland. |
Red bone marrow | A primary lymphatic organ found in vertebrae, end of long bones, the skull. These bones produce stem cells that differentiate into various white blood cells. |
Thymus gland | Located in chest. The role of the thymus is to be the location where T-lymphocytes mature. T-lymphocytes learn how to differentiate between self and non-self cells. |
Secondary lymphatic organs | Spleen, lymph nodes, tonsils |
Spleen | A secondary lymphatic organ what helps fight pathogens that are in the blood. Pathogens are killed as blood filters in the spleen. |
Lymph nodes | A round structure that contains B-lymphocytes and a sinus, surrounded by a capsule. When the lymph moves into the lymph node, B/T-lymphocytes kill pathogens. |
Lymphatic nodules (tonsils) | These tissues are not surrounded by capsules, but contain B/T-lymphocytes to aid in immunity. The tonsils are some of the first organs to react to pathogens. |
Physical barriers of entry | These barriers prevent pathogens from entering the body. They include the skin, mucous membranes, and ciliated cells. |
Chemical barriers of entry | Sebaceous secretions, saliva, tears, and normal flora. |