1540s, belonging to an ecclesiastical metropolis, from Late Latin metropolitanus, from Greek metropolites resident of a city, from metropolis (see metropolitan (n.)). Meaning belonging to a chief or capital city is from 1550s. In reference to underground city railways, it is attested from 1867.
The solution that runs through these vessels, called lymph, begins in the circulatory system as blood plasma and then is converted to a fluid known as an interstitial or intercellular fluid. This fluid is responsible for delivering hormones, oxygen, and various nutrients to cells throughout the body.fferent vessels transport fluid into the lymph nodes, while efferent vessels carry filtered lymph away from the lymph nodes. White blood cells called lymphocytes are a major part of the lymphatic system. Lymph nodes may become swollen when a person gets sick.
Once lymph fluid reaches the lymph nodes, it is filtered and treated. The lymphatic system is part of the body's immune system and foreign cells that arrive in the lymph nodes are attacked by immune system cells.After the lymph fluid is concentrated within the lymph nodes, it is filtered into the bloodstream where the kidneys capture the waste material and pass it over to the bladder.You can see your lymphatic system working when you see swelling go down around an injury.fter the lymph fluid is concentrated within the lymph nodes, it is filtered into the bloodstream where the kidneys capture the waste material and pass it over to the bladder. You can see your lymphatic system working when you see swelling go down around an injury.