artery

[Ger. arterie; Fr. artère; Sp., Port., Ital., and Lat. arteria; Gr. ἀρτηρία ( arteria ) = the windpipe or trachea; (2) an artery, from ἀήρ ( aer ) = air, and τηρέω (tereo) =to watch over; τηρός ( teros ) = a watch, a guard. So called because the ancients, finding that, in the dead bodies which they examined, the arteries were empty of blood, took up the very erroneous notion that they were designed for the circulation of air through the system. Thus Cicero says, "Spiritus ex pulmone in cor recipitur et per arterias distribuitur, sanguis per venas." "(Cicero, De Nat. Deorum, ii. 55, 138.) This error was not shaken by Hero phil us.] One of the ve els designed to convey the blood from the heart. arteries are long cylindrical tubes, with three coats, an external tunic commonly called the cellular coat, a middle or fibrous tunic or coat, and an epithelial tunic. The coating of the arteries is very elastic. The largest arteries which leave the heart are the norta and the puimonary artery both spring from the base of the heart in front. They branch and anastomose to a large extent. The contractility of the arteries forces the blood to the extremities from the heart, the valves of which prevent its return. "The prominent difference between blood drawn from the arteries and The that from the veins is to be found in the bright scarlet colour of the former and the dark red, almost black, of the latter." ( Todd and Bowman: Physiol. Anat ., vol. ii., p. 310.) "The chief arteries , so frequently run in abnormal courses that it has been found useful for surgical purposes to calculate from 12,000 corpses how often cach course prevails."- Darwin : Descent of Man, vol. i. (1371), pt. i., ch. iv.