Applied Physiology Part 1

Applied Physiology.

by Frank Overton.

PREFACE

This primary text-book of applied physiology follows a natural order of treatment. In each subject elementary anatomical facts are presented in a manner which impresses function rather than form, and from the form described derives the function. The facts and principles are then applied to everyday life. Anatomy and pure physiology make clear and fix hygienic points, while applied physiology lends interest to the otherwise dry facts of physiology and anatomy. From the great range of the science there are included only those subjects which are directly concerned in the growth and development of children.

The value of a primary book depends largely upon the language used. In bringing the truths within the comprehension of children, the author has made sparing use of the complex sentence. He has made the sentences short and simple in form, and logical in arrangement.

A child grasps new ideas mainly as they appeal directly to the senses.

For this reason, physiological demonstrations are indispensable.

Subjects for demonstrations are not given, because they cannot be performed by the children; but the teacher should make free use of the series given in the author's advanced physiology.

Cuts and diagrams are inserted where they are needed to explain the text. They are taken from the author's _Applied Physiology, Intermediate Grade_. Each was chosen, not for artistic effect, but because of its fitness to ill.u.s.trate a point. Most of the cuts are adapted for reproduction on the blackboard.

The effects of alcohol and other narcotics are treated with special fulness. The subject is given a fair and judicial discussion, and those conclusions are presented which are universally accepted by the medical profession. But while this most important form of intemperance is singled out, it should be remembered that the breaking of any of nature's laws is also a form of intemperance, and that the whole study of applied physiology is to encourage a more healthy and a more n.o.ble and self-denying mode of life.

CHAPTER I

CELLS

Our body is made of many parts. Its head thinks. Its legs carry it, and its arms and hands take hold of things. The leg cannot do the work of the arm, nor the head do the work of the hand; but each part does only its own work.

=1. The simplest animal.=--Some animals have parts like a man's; but these parts are fewer. No animal has arms or hands like a man. A fish has little fins in place of legs and arms, while a worm has not even a head, but only a body, and yet it moves. An oyster has only a body and cannot move. The simplest of all animals is very small. A thousand of them would not reach an inch. Yet each is a complete animal. It is called the _ameba_. It is only a lump of jelly. It can put out any part of its body like an arm and take a lump of food. This same arm can eat the food, too. It can also put out any part of its body like a leg and move by rolling the rest of its body into the leg. It can do some things better than a man can do them, for any part of its body can do all kinds of work. So the ameba grows and moves and does as it likes.

[Ill.u.s.tration: =Different forms of an ameba (400).=]

[Ill.u.s.tration: =Cells from the human body (200).=

_a_ A colored cell from the eye.

_b_ A white blood cell.

_c_ A connective tissue cell.

_d_ A cell from the lining of the mouth.

_e_ Liver cells.

_f_ A muscle cell from the intestine.]

=2. Cells.=--A man's finger moves and grows something like a separate animal, but it must keep with the rest of the body. A little piece of a finger moves and grows, too. If you should look at a finger, or any other part of your body, through a microscope, you would see that it is composed of little lumps of jelly. Each little lump looks like an ameba. We call each lump a cell. The cells make up the finger.

=3. What cells do.=--Each cell acts much as an ameba does. From the blood it gets food and air and takes them in through any part of its body. It also grows and moves. But the cells are not free to do as they wish, for they are all tied together in armies by very fine strings. We call these strings _connective tissue_. One army of cells makes the skin, and other armies make the bones and flesh. Some armies make the fingers, and some the legs. Every part of our body is made up of armies of separate cells.

=4. The mind.=--The body is a home for the mind. The cells obey the mind. The mind pays the cells by feeding them and taking good care of them. When an army of cells is hurt, the body feels sick, and then the mind tells the whole body to rest until the cells are well again. When we study about a man's body, we learn about the separate cells in his body.

WHAT WE HAVE LEARNED

1. Our body is made up of many small parts.

2. The smallest parts are each like a little animal, and are called _cells_.

3. Each cell eats and grows.

4. One army of cells makes a finger and another a leg, and so on through the body.

5. The mind lives in the body.

6. The mind takes care of the cells.

CHAPTER II

OF WHAT CELLS ARE MADE

The cells of our body are made of five common things. You would know all these things if you should see them.

=5. Water.=--The first thing in the cells is _water_. Water is everywhere in the body. Even the teeth have water. Most of our flesh is water. Without water we should soon shrink up. Our flesh would be stiff like bone and no one could live.

[Ill.u.s.tration: =The body is made of these five things.=]

[Ill.u.s.tration: =Fat tissue (100).= The liquid fat is stored in living pockets.]

=6. Alb.u.min.=--_Second_, next to water, something like the white of an egg makes the most of the body. The white of an egg is _alb.u.min_.

When dried it is like gelatine or glue. Alb.u.min makes the most of the solid part of each cell. Lean meat and cheese are nearly all alb.u.min.

When it is heated it becomes harder and turns white. The word alb.u.min means white. Dry alb.u.min is hard and tough, but in the living cells it is dissolved in water and is soft like meat. It is the only living substance in the body, and it alone gives it strength.

=7. Fat.=--_Third_, next to alb.u.min, the most of the body is fat. Fat does not grow inside the cells of the body, but it fills little pockets between the cells. Fat does not give strength. It makes the body round and handsome. It also makes the cells warm and keeps them from getting hurt.

=8. Sugar.=--_Fourth_, sugar also is found in the body. Sugar is made out of starch. When we eat starch it changes to sugar. Starch and sugar are much alike. We eat a great deal of starch and sugar, but they are soon used in warming the body. Only a little is in the body at once.

=9. Minerals.=--_Fifth_, there are also some minerals in the body.

When flesh is burned they are left as _ashes_. Salt, lime, iron, soda, and potash are all found in the body.

[Ill.u.s.tration: =Starch grains (400).=

_a_, of potato.

_b_, of corn.]

Everything in the body is either water, alb.u.min, fat, sugar, or minerals. These things are also our food. We eat them mixed together in bread, meat, eggs, milk, and other foods.

=10. Life.=--Our food is not alive, but after we eat it the body makes it alive. We do not know how it does it. When the body dies we cannot put life into it again. There is life in each cell.