What Is Creatinine? Creatinine is a chemical waste product in the blood that passes through the kidneys to be filtered and eliminated in urine. The chemical waste is a by-product of normal muscle function. The more muscle a person has, the more creatinine they produce. Levels of creatinine in the blood reflect both the amount of muscle a person has and their amount of kidney function.
The lymph system and lymphoid tissue. To know what lymphoma is, it helps to understand the bodyâs lymph system. The lymph system (also known as the lymphatic system) is composed mainly of lymphoid tissue, lymph vessels, and a clear fluid called lymph.Lymphoid tissue includes the lymph nodes and related organs that are part of the bodyâs immune and blood-forming systems, such as the spleen and bone marrow.ymphocytes. Lymphoid tissue is made up of several types of immune system cells that help the body fight infections. Most of the cells in lymphoid tissue are lymphocytes, a type of white blood cell. The main types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells).
Lymph nodes are small round organs that are part of the bodyâs lymphatic system. They are found widely throughout the body and are connected to one another by lymph vessels. Groups of lymph nodes are located in the neck, underarms, chest, abdomen, and groin. A clear fluid called lymph flows through lymph vessels and lymph nodes. Anatomy of the lymphatic system, showing the lymph vessels and lymph organs, including lymph nodes, tonsils, thymus, spleen, and bone marrow. One inset shows the structure of a lymph node and the lymph vessels, with arrows showing how lymph and immune cells called lymphocytes move into and out of the lymph node.