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.
Lymph. Lymph is a fluid that circulates throughout the body in the lymphatic system. It forms when tissue fluids/blood plasma (mostly water, with proteins and other dissolved substances) drain into the lymphatic system. It contains a high number of lymphocytes (white cells that fight infection).