Corpuscle

Part of speech: noun (n.)

1. A minute particle; an atom; a molecule.

2. A protoplasmic animal cell; esp., such as float free, like blood, lymph, and pus corpuscles; or such as are imbedded in an intercellular matrix, like connective tissue and cartilage corpuscles. See Blood. Virchow showed that the corpuscles of bone are homologous with those of connective tissue. Quain's Anat. Red blood corpuscles (Physiol.), in man, yellowish, biconcave, circular discs varying from 1/3500 to 1/3200 of an inch in diameter and about 1/12400 of an inch thick. They are composed of a colorless stroma filled in with semifluid hæmoglobin and other matters. In most mammals the red corpuscles are circular, but in the camels, birds, reptiles, and the lower vertebrates generally, they are oval, and sometimes more or less spherical in form. In Amphioxus, and most invertebrates, the blood corpuscles are all white or colorless. -- White blood corpuscles (Physiol.), rounded, slightly flattened, nucleated cells, mainly protoplasmic in composition, and possessed of contractile power. In man, the average size is about 1/2500 of an inch, and they are present in blood in much smaller numbers than the red corpuscles.