respiration

the whole process by which air is drawn into and out of the LUNGS , during which oxygen is absorbed into the blood-stream and carbon dioxide and water are given off. External respiration is the actual process of breathing and the exchange of gases that takes place in the lungs. Internal respiration is the process by which oxygen is given up from the blood CIRCULATION to the tissues, in all parts of the body, and carbon dioxide is taken up to be transported back to the lungs and eliminated. The process of drawing air into the lungs is known as inhalation or inspiration and expelling it out is exhalation or expiration. The rate at which this occurs is known as the respiratory rate, and it is about 18 times a minute in a static healthy adult.