Respiration

(rès-pe-ra's hun.) [From L. respiro, I breathe back.] (Physiol.) A function proper to animals, the object of which is, to place the materials of the blood-the mixture of the venous blood with lymph and chyle -in contact with atmospheric air, in order that it may acquire the vivifying qualities which belong to arterial blood. The organs for executing this function are, in the mammal i a, birds, and reptiles, the lungs. In man, the R. consists of mechanical and chemical phenomena. The mechanical are Inspiration and Expiration. The evident chemical phenomena consist in the formation of a certain quantity of carbonic acid, the absorption of a part of the oxygen of the air, and the disengagement of a quantity of water in the state of vapor. In the healthy condition the R. is easy, gentle, regular, and without noise. In man, the respirations are generally about 35 per minute in the first year of life; 25 during the second; 20 at puberty; and 18 in the adult age-during which time he inhales abt. 18 pints of air. The air drawn in and expelled by the lungs in R. is called breath. See BRONCHI, LUNGS, . [s. 764]