209 MEDICAL HOME NUR,SING CoittiHued/roin pa<:t J7, I'url x THE PROCESS OF RESPIRATION A Scientific Explanation of the Breathing Process— The Physiology of the Respiratory Organs- Asphyxia — Diseases of the Lungs and Chest forward with each deep breath we take. Tight corsets, of course, cur- tail the action of the dia- phragm, and that is why women breathe more with the upper part of the chest, and men breathe rather more with the ab- domen, using the diaphragm freely. With every breath, the chest walls contract and dilate like a bellows, forcing the air out and sucking it in al- ternately, thus renewing the air in the lungs. Arch of Aorta Left Pul- moiury Vein Left Puliiioiuuy Artery Heart and great vessels with lungs turned back T here are two lungs, one on each side of the chest, or thorax, and the heart with its great blood'Vesseis lies between 'T'he first article of this series dealt briefly with
- the circulation of the blood. Blood is the
vehicle which feeds the tissues with oxygen. The arterial blood carries the oxygen to the tissues ; the venous blood takes back carbonic acid gas and other waste substances to the heart and thence to the lungs. In the lungs, this carbonic acid is given off and a new supply of oxygen is absorbed by the process of respiration. The Respiratory Organs The respiratory organs consist of the nose, pharynx, larynx, trachea, or windpipe, and the bronchial tubes, which open into innumerable air sacs covered by a fine, dense network of blood- vessels, the whole mass of which form " the lungs." There are two lungs, one on each side of the chest, or thorax, and the heart with its great blood-vessels lies between. The lungs are covered by a fine, transparent membrane, the pleura, which also lines the whole inner surface of the chest. The lungs are pinkish grey, mottled with black, and in shape they are conical. The bases lie upon the diaphragm, and the apex of each lung extends up to the root of the neck above the collar-bones. The diaphragm is a sheet of muscle which divides the interior of the body into two. Above the diaphragm lies the thorax, or chest, which contains the heart and lungs. Beneath the diaphragm is the abdominal cavity with its organs of digestion, the stomach, intestines, liver, etc. The diaphragm lies about the level of the waist and descends and ascends with every respiration we take in deep breathing. When the diaphragm sinks and forces the stomach and intestines downwards, the size of the abdominal pavity is reduced and the abdominal wall comes The "Air Passages" The air is drawn in through the nose and passes down the pharynx, or throat, through the larynx, or organ of voice, until it comes to the trachea. Laryux Trachea ;. ^ The air passages. This diagram shovA^s how the tiny bronchi divide and subdivide like the stem of a tree until they arc so minute in size they can divide no more. The trachea, or vindpipe, is a strong, carti- laginous tube which passes down the neck to the upper part of the chest, where it divides into two bronchi, one going to each lung. Now the bronchi divide and subdivide like the ftem of a tree until they are so minute in size
