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.

    7/376 (page 5)
    ROYAL ARMY MEDICAL CORPS TRAINING SECTION I.—THE HUMAN BODY CHAPTER 1 : AN OUTLINE * 1. The microscope shows that the human body is made up of countless small cells. Indeed all living things—both animals and plants—are made of cells; and these may be regarded as the bricks that form the living structure. But, unlike a brick, each cell has a life of its own. Life means activity ; and in all live cells, even when they are not obviously moving or growing or dividing, chemical changes are always taking place. This activity—like the activity of an internal-combustion engine—is impossible without (a) a supply of oxygen, and (b) a supply of fuel. A cell, like an engine, must also have means of getting rid of any parts of its fuel (food) that it cannot use (waste-products). The simplest animals and plants consist of single cells, drifting about in ponds or the sea. Their very thin walls allow oxygen and food to come in, and waste-products to go out. | But when an animal, instead of being one cell, or a few hundred, is composed of thousands of millions of cells, the problem of keeping them all alive is far more difficult. Instead of being surrounded by water, or even by air, most of the cells of the human body are surrounded by other cells. Hence elaborate arrangements have to be made to ensure that every one of them receives the oxygen and fuel it needs for its work, and is also able to get rid of its waste. 2..The-blood.—If a man is healthy and is properly fed, his blood contains in liquid form ali the food the cells require. His heart pumps the blood through a system of pipes (arteries) * This chapter can be read as an introduction, but the beginner necd not try to master its contents completely. He can return to it later when he wants to draw together the knowledge gained from studying the parts of the body separately.