Royal Army Medical Corps training pamphlet / War Office.

Date:
1944
Catalogue details

Licence: Public Domain Mark

Credit: Royal Army Medical Corps training pamphlet / War Office. Source: Wellcome Collection.

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    Whenever the demand of the muscles for oxygen is increased by special exertion, the rate of breathing is increased and more oxygen enters the blood. Power to make a successful physical effort, such as winning a race, largely depends on ability to provide the muscles with all the oxygen-containing blood they need for their work and for the removal of waste-products. If they do not get enough of this refreshed blood from the lungs they become tired and eventually cease to contract. Practice and training enable runners and other athletes to increase the blood-supply of their muscles enormously at short notice, but with violent and prolonged exercise the immediate removal of all waste-products can scarcely be expected. To the ‘‘ untrained”’ the feeling of stiffness caused by accumulation of waste-products in muscles is all too familiar, CHAPTER 4 THE BLOOD AND THE LYMPH 40. Strictly speaking, blood is not a red fluid. It is a pale yellow fluid containing immense numbers of solid cells, most of which are red. The solid cells can be separated from the liquid plasma, just as cream can be separated from milk. _-The plasma is the part of the blood that carries food round the body. As the blood flows through the thin-walled blood- vessels (capillaries), the food substances dissolved in the plasma pass through the vessel walls and enter the fluid (lymph) in which the cells are bathed. In exchange the lymph hands over any waste-products produced by the celis, and these waste- products are later removed from the plasma when it travels through the kidneys, lungs and skin. 41. The red cells.—The red cells or ved corpuscles floating in the plasma are responsible for carrying oxygen round the body. They contain a red substance called hemoglobin which easily forms a chemical compound with oxygen. When the blood is passing through the lungs the hemoglobin picks up oxygen from the air and turns it into the chemical compound oryhemoglobin. But as soon as it reaches any part of the body where there is a shortage of oxygen it gives up its oxygen | and becomes hemoglobin again. Thus each red corpuscle, in its circular journey through the blood-vessels of the body, carries a load of oxygen from the lungs to the oxygen-hungry tissues, and then returns to the lungs for more.