The human body. A beginner's text-book of anatomy, physiology and hygiene ...

Front matter

SheKJ)Lj^3

UNITED STATES OF AMERICA.

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Preface

This little book is an attempt to express accurately and yet in simple language, those facts concerning the structure and actions of the living human body which it is desirable, for practical purposes, that every one should know. It is essentially a school-book of personal hygiene. Little, if any, more Anatomy and Physiology is introduced than is necessary to make clear the reasons, as regards the preservation of health, for following or avoiding certain courses of conduct. This, of course, includes all the broad facts of Human Anatomy and Physiology; but subjects of merely professional importance or of purely scientific interest have been omitted. As regards Hygiene, attention is for the most part only directed to matters which are usually within the easy control of each individual. It seems useless to burden boys and girls with sanitary laws which need the aid of a physician or engineer for their successful application.

A very earnest attempt has been made to present the subject so that children may easily understand it, and, wherever possible, to start from familiar facts and gradually lead up to less obvious ones. In this part of the task, which was really the most difficult, I have had so much aid from my wife's experience in teaching young pupils, that her name properly has a place on the title-page.

IV PREFACE,

We both desire to express our obligations to Miss Frances T. Bauman, who placed freely at our disposal the results of her long and eminently successful experience in teaching Physiology to children.

As appendices to certain of the chapters there are practical directions for the illustration of various facts in Anatomy and Physiology, which can be shown to pupils without any special apparatus, or any material not easily obtained.

Particular attention has been given to the action on the body of the more commonly abused stimulants and narcotics, especially alcohol.

H. Newell Martin.

Johns Hopkins University, June 30, 1884.

Contents

CHAPTER PAGE

I. The General Plan on which the Human Body is Built.. . i

II. The Skeleton 12

Chapter I. The General Plan On Which The Human Body Is

BUILT.

1. Why we should Learn about our Bodies. — Suppose you had given to you a delicate instrument, such as a watch: you would desire to be told something of the way it was made, how it w^as to be used, and what was apt to harm it. Even a little knowledge of these things would help you to take better care of the watch.

Now every one of us is responsible for the care of a body made up of many more parts than we find in a watch, and any of them liable to be injured in numberless different ways. If all the parts work well we are in healthy able to enjoy our lives, do our work, and aid those who are less fortunate. If we lose our health we not only can do less and enjoy less ourselves, but are likely to become a burden upon others. It is therefore one of

T. If you have a watch, what ought you to know of it, and why? What is the nature of the machine given to every human being to take care of ? If it is kept in good order, what is the result ? If not ? What then is our duty with regard to it?

2 ANATOMY AND PHYSIOLOGY,

our first duties to learn enough about our bodies to be able to avoid doing things likely to harm them, or neglecting to do that which is for their welfare.

2. What Anatomy is. — We could not look at the watch without seeing that it was made up of different pieces, as case, and face, and hands; and a glance at the works inside would show us that dozens of parts, such as wheels, and pivots, and springs, and screws, without which the portions we see on the outside would be useless, were fixed together in a special way to make the watch.

Likewise, on looking at the outside of the body you easily perceive head, and neck, and trunk, and arms, and legs; and if you could see into the inside you would find hundreds of other parts, which move the parts you see and make them useful. The science which teaches us the shape and size of all the parts of the body, where they are placed in it, and how they are joined together, is named Human Anatomy,

3. What Physiology is. — On examining the parts of which a watch is made we find that each has its use: the case to protect the works, the glass to let us see the face and yet keep out dust, the hands to show the hour, th spring to keep it going, and so forth.

In like way it is found that the various parts of the body have their uses: as the eyes to see, the mouth to eat, the legs to walk with. The science which teaches the uses of all the parts of the body, more particularly of its inner parts, is named Human Physiology,

2. What do we easily find out on examining a watch? In this r'^- spect how may the body be compared to a watch? What is Humai. Anatomy ?

3. Why are there many parts in ^ watch ? In the body ? What is Human Physiology ?

HYGIENE. 3

4. What Hygiene is. — Lastly, when you had learned something of how the watch was made and what each part of it had to do you would know that certain things must injure it; that it should be kept dry lest the steel springs rust, and that the case must be kept closed to prevent dust and grit from getting into the works. You might also be told some things which it would take you a longer time to find out for yourself; as, for example, that if the watch is to be a good time-keeper it must be regularly wound up, and not at one time one day and at another the next, or perhaps quite forgotten a third.

So, without learning much Anatomy and Physiology you will readily see that certain things must be bad for your body: such as getting wounds that will cause great loss of blood, or going without food. The harmfulness of other things it might take you a long time to find out by yourself; as, for example, that by breathing foul air or taking too little sleep, eating imprudently or drinking what is called *^ spirits," you might very easily injure your body beyond cure. Unless you were warned you would probably not discover the danger until too late to avert it.

Just as a watchmaker could save you a great deal of time and risk by giving the results of his experience as to the best way to manage a watch, physicians and others who have made a study of what is good and what bad for the human body can save us much labor and danger by telling what they have found out. The science which

4. Having examined a watch, what would at once occur to you about its preservation ? What studies teach you that certain %ings would be bad for your body ? Name some injurious habits that the experience of others warns you to avoid. What is meant by Hygiene?

4 ORGANS AND TISSUES.

teaches what is good and what nurtful to our bodies — in other words, how we may best preserve our health — is known as Hygiene,

5. Organs and Functions. — The separate parts of which the body is made up are called organs: thus the eye is the organ of sight, the teeth are organs of chewing, the stomach is an organ of digestion. The use of any organ is spoken of as its function : thus the function of the eye is seeing, of the ear hearing, of the hand grasping.

6. The Structure of Organs. — The human body, like a watch, not only has numerous parts, but these parts are made of different materials. Taking the hand, for example, we observe on the outside, skin, nails, and hairs. If the skin were removed we should see below it some fat, just like that in beef and mutton. Under the fat, in the ball of the thumb you would find some red flesh, called muscle, which answers to the lean of meat. Beneath all the rest would be white hard bones. At the finger-joints where the ends of separate bones come near together you would see covering each a thin layer of gristle or cartilage. And binding together the skin and fat and muscles and bones would be found a stringy substance which, as it unites all the rest, is called the con- ^ nee live material.

7. Tissues. — Each kind of material used in constructing the body is called a tissue: and each tissue has its own peculiar properties. Connective tissue is tough and suited

5. What is an organ ? Give examples. What is a function ? Illustrate.

6. What is meant by the structure of an organ ? Describe the structure of the hand.

7. What is a tissue ? Name and describe some tissues. Name some liquids of the body.

THE PLAN ON WHICH MAN'S BODY IS BUILT, 5 to bind parts together. Bony tissue is stiff and useful to support softer parts. Cartilage tissue is elastic and forms admirable springy cushions between the hard bones. Muscle tissue has power to move parts to which it is joined; and so on.

In addition to the solid tissues, liquids form part of the body: as the blood which we see flow from a cut finger, and the saliva which moistens the mouth.

8. The General Plan on which the Body is Built. — If a man's body were sawed in two down the middle, so as to separate it into right and left halves, we should see something like Fig. i, if we looked at the cut surface of the right half. On examining

the figure you see that there are Fig. i.— a section along the middie of head, neck, and trunk. <5,

two chief cavities or chambers the chest, and c, the abdominal

division of the ventral cavity sep-

in the body, havins: between them crated by the diaphragm, d. a',

-' ' ^ the enlarged upper end of the dor-

the row of bones e e; these bones -! ^^^S'e Twt nfrrowe' pt^ together form the back-bone or °^i*1 ^°rT'^'"Jf rthe'pTtftio^

r^j.:..^ TU^ ^U«,^K^*. Z? /^ :.^ formed by the back-bone between

Spine. Ihe chamber, B, C, m the ventral and dorsal cavities. /,

r ^r^uuiu • 1- t^^ nose. 0, the mouth. /, the

iront 01 the back- bone is much lungs; the tube leading down to

. , . . , - them is the windpipe. ^, the

the larger; it is named the zfen- heart, y, the stomach; the tube

leading down to it is the gullet; tral cavity. The other chamber, the tube passing from the stomach

to the lower end of the trunk is the a, a\ is the dorsal cavity. intestine. k, a kidney. s, the

-^ sympathetic nervous system.

8. How does the plan on which a watch is made compare with that on which the body is constructed ? In a human body cut down the middle what chief divisions would you find ?

6 THORAX AND ABDOMEN.

9. The Ventral Cavity, as you perceive in the figure, does not reach up into the neck or head. It exists only in the trunk of the body, and is divided into an upper story, B^ the chest or thorax^ and a lower story, C, the abdomen^ by a partition, d^ which forms the floor of the thorax and the ceiling of the abdomen. This partition is the diaphragin. How far in your own body the chest-cavity extends you can find out pretty accurately by beginning at the bottom of the neck and feeling down along the middle of the front of your trunk till you feel no more bones through the skin: that level marks the bottom of the thorax.

10. Contents of the Thorax. — On Fig. i you will also see that the mouth, o^ and the nose, /, join behind, and that from the place of meeting two tubes run down the neck. The front one of these tubes is the windpipe or trachea; after entering the thorax it ends in the lungs^ I. In the thorax is also placed the hearty h.

11. Contents of the Abdomen. — The second of the tubes above referred to is the gullet or oesophagus. It runs right on through the chest and diaphragm into the abdomen, and there opens into the stomachy f.

The air we take in when breathing goes along the windpipe to the lungs, but no further: the food and drink which we swallow take a longer road along the gullet to the stomach.

In addition to the stomach, the liver^ the intestines or bowels^ and the kidneys^ k^ lie in the abdomen.

9. Where is the ventral cavity ? Name its divisions. The partition. How can you trace the chest or thorax in your own body ?

10. Name contents of thorax.

11. What is the course of the gullet? Its use ? Use of the windpipe ? Name the organs which lie in the abdomen.

CONTENTS OF THORAX AND ABDOMEN, 7

12. What would be seen if the front of the Thorax and Abdomen were cut away. — This is represented in Fig. 2. Stretching across from side to side is seen the diaphragm,

Fig. 2. — The trunk of the body opened from the front to expose the contents of the ventral cavity, zz, the diaphragm ; /«, lu\ the lungs ; h^ the heart ; ma^ the stomach; /«/, the spleen; ne^ ne, the membrane {great omentum) which lies in front of the intestines and kidneys.

12. Name the parts which would be exposed if the front wall of chest and abdomen were cut away. State their positions.

8 VERTEBRATE ANIMALS.

z z. Above the diaphragm, in the thorax, are the lungs^ lu, lu. Between the lungs is the hearty h^ partly covered by fat and other things. Below the diaphragm is the liver^ le^ /^', the stomachy ina^ and the spiee?t, mi. Hanging down from the stomach is a sort of apron, 7ie^ ne; if it were lifted up we should find behind it the intestines and the kidneys.

13. The Dorsal Cavity (a, a', Fig. i) is found in the head and neck as well as in the trunk of the body. If the back or top of a man's head were cut away the upper end of the dorsal cavity would be opened and we should find it to be a large chamber having the brain^ N\ in it. In the neck and trunk the dorsal cavity is a narrow tube containing in its upper two-thirds the spinal cord, JV,

14. Man is a Vertebrate Animal. — The presence of the ventral and dorsal cavities with a hard partition between them is a chief fact in the anatomy of the human body : it shows that man is a vertebrate animal^ that is to say, is a back-boned animal., and belongs to the same great group as fishes, reptiles, birds, and beasts. Worms, clams, and insects are invertebrate a^timals, that is, have no back-bone.

15. Man's Place among Vertebrates. — We have seen that man is a vertebrate, or back-boned animal. Though all vertebrates are alike in the general plan of their structure, there are such differences that zoologists divide them into classes. The most important of these

13. Where does the dorsal cavity lie ? Name its contents and give their position.

14. Why is man a vertebrate animal ? Name some other vertebrates. How are vertebrates distinguished from invertebrates ? Give examples of invertebrate animals.

15. Why are vertebrates divided into classes? To which class does man belong? Name some other mammalia. How do mammalia differ from other vertebrates ?

CHEMISTRY OF HUMAN BODY, 9

classes is the mammalia, to which man belongs. Ordinary four-footed beasts, and monkeys, are also mammalia. The mammalia differ from all fishes, reptiles, and birds, first, in the possession of organs, the mainmary glands, which provide milk for the young; sec9nd, in possessing hair; third, in having the chest separated from the abdomen by a diaphragm.

16. The Intellect of Man makes him superior to any other animal and supreme in the world.

His power to form conceptioiis of right and wrong and his knowledge of moral responsibility give him yet greater superiority. But as a material object only, do anatomists study man's body, and they therefore classify it among the bodies of other animals according as it differs from or resembles them in the arrangement of its parts.

17. Chemistry of the Body. — Suppose you put a green stick into the fire: what happens? At first it hisses and gives off steam; then it begins to burn; if you draw it out when half burned you find it a black mass of charcoal ; if you put it back you find most of the charcoal will burn away, but some ashes will be left which you cannot make burn. If, instead of a green piece of wood, a man's body be burned, we find the same results. From this we learn (i) that the body contains water; (2) that it contains solid things which will burn; (3) that it contains solid matters, the ash, which will not burn.

16, What makes man superior to all other animals? What gives him yet greater superiority? From what standpoint is n^an studied by anatomists? How classified ?

17. What would be the action of fire on green wood? On man's body? Hence what do we learn? What name is given the materials which burn up ? What those which will not burn ? Of what is every tissue composed? In which do we find most water? Mineral matter? Animal matter?

10 SUMMARY,

The things going to make up the body and capable o being burned are known as animal matters; the ashes are mineral matters. In every tissue of the body there are water, animal matter and mineral matter. In some a great deal of wate^, as in the blood; in others a great deal of mineral matter, as in the bones and teeth, which owe their hardness to lime; in still others a great deal of animal matter, as in fat and muscle: but everywhere some of all three.

18. Summary. — Anatomy is concerned with the form and structure of the parts of the body.

Physiology with the uses of the parts and the ways in which they work.

Hygiene with the conditions of life which promote the health of the body.

The materials of the body are hard or soft, solid or liquid, and are fitted for different purposes.

Tissue is the name given to each of the materials, whether blood, bone, muscle, fat, or any other.

The organs are formed of tissues combined in various ways. Each organ has its own particular duty, or function^ which in health it performs in harmony with all the others.

Vertebrates are animals having back- bones — such as man, beasts, birds, reptiles, and fishes. Their bodies contain two main cavities, dorsal and ventral. In the dorsal cavity are the brain and spinal cord. The ventral cavity contains lungs, heart, stomach, liver, intestines, and kidneys.

i8. What does anatomy deal with ? Physiology ? Hygiene ? What have we learned of the materials of the body ? Of tissue ? Of the organs ? Of vertebrates ? Of invertebrates ? Of mammalia ? Of the chemical constituents of the bodv?

SUMMARY. II

Invertebrates are animals having no back-bones — such as worms, clams, and insects.

Alammalia is the highest of the several classos of vertebrates and includes man, monkeys, and four-footed beasts. It is characterized by the presence of mam?nary glands; by the fact that the ventral cavity is separated into chest and abdo?nen by the diaphragmj and by having more or less of the surface covered with hair.

Water ^ animal matters and mineral matters compose the body. If it be burned the animal matters are consumed; the mineral matters remain in the form of ashes.

Chapter II. The Skeleton

1. The Skeleton.— By the skeleton of any animal we usually mean those hard parts which remain behind when the softer parts have decayed; as the shell of a clam or crab, or the bones of a bird or beast. In our own bodies, bones form the chief part of the skeleton; but other things help. A very young infant has a skeleton, but this skeleton is made for the most part of cartilage^ ox gristle^ and not of bone. As the child grows, more and more bone takes the place of the cartilage; but even in old age some cartilage remains. Moreover, a skeleton consists not merely of all the bones of a body, but of all the bones united together in their proper places. In our bodies they are bound together by tough stringy connective tissue. The skeleton of the living body, as distinguished from a dead skeleton made of dry bones joined together by wires, is therefore made up of three different things; namely, bones, cartilages, and connective tissue.

2. The Bones, two hundred and six in number (see table, p. 22), form the hardest, and stiffest, and heaviest

1. What is a skeleton? What change takes place in the skeleton of a child as it grows ? How are the bones of a skeleton put together ? What are the materials of the living human skeleton ?

2. Number of bones in the skeleton ? What part of it do they make? How do they provide support? Protection? How concerned in movement ?

PLATE I.-THE BOXES, JOINTS, AIS^D LIGAMENTS.

EXPLANATION OF PLATE I.

A front view of a human skeleton with the ligaments and some of the cartilages in place.

For the names of the bones see the description of figure 3.

a Ligaments of the Elbow-Joint.

b The Ligament which is connected to the ventral surfaces of the bodies of

the Vertebrae. € Ligament connecting the Innominate Bone to the Spine. / Ligament connecting the Innominate Bone to the Sacrum. g The Ligaments of the Wrist-Joint. h The connective-tissue Membrane which fills up the interval between the two

bones of the Forearm.

I A similar Membrane between the two bones of the Leg, and, lower down,

I, ligaments of the Ankle -Joint. k A connective-tissue Membrane which fills up a hole in the Innominate Bone. n Ligaments of the Knee-Joint. o o Ligaments of the Toes and Fingers. p Capsular (bag -like) Ligament of the Hip Joint. q Capsular Ligament of the Shoulder-Joint.

CARTILAGE.— CONNECTIVE, TISSUE. 13

part of the skeleton. United in various ways, they provide a strong framework which supports the softer organs, and in some places, as the skull (Fig. 6) and thorax (Fig. 5), make strong boxes or cages in which delicate organs, such as the brain or lungs, lie safe. The bones are also concerned in the movements of the body; nearly all muscles pull first on some bone or other, and when the bone is made to move, it of course carries with it the surrounding soft parts.

3. Cartilage is what we know in meat as gristle : it is stiff enough to keep its shape, but can be bent with tolerable ease; it is also elastic, so that it springs back to its proper shape, like a piece of whalebone, as soon as the force which has bent it ceases to act. You can easily feel on your nose the difference between bone and cartilage. The skeleton of that part of it near the forehead is made of bone, and that of the lower part of cartilage. We can push the tip of the nose to either side, or up and down, but when we stop pressing, it returns to its place. The skeleton of that part of the ear which projects from the side of the head is also made of cartilage.

Cartilage is used in parts of the skeleton which have to be moderately stiff, but at the same time pliable and elastic.

4. Connective Tissue is used for several different purposes in the body. To understand this, let us imagine a quantity of very fine strands of silk, some twisted into

3. What is cartilage ? Its properties? How used in the nose ? In the ear ? Throughout the skeleton ?

4. To what may connective tissue be compared ? Name and character of its threads ? How are the cords made? The membranes? The loose portion ? Where do we find networks of connective tissue ? Give an example.

14 A CTION OF ALCOHOL OM CONNECTIVE TISSUE.

strong cord or rope, some woven into firm bands, some left in loose masses, and some made up into fine network. Connective tissue consists of threads, called fibres^ which are much tougher and finer than any strand of silk. In some parts of the body these threads are united to form cords named ligame7its^ which bind bones together. Elsewhere the fibres are woven into bands or meinbranes which surround and support various parts. Lying in the crevices between different organs, forming a soft packing for them, we find loose fluflfy bundles of connective tissue. Finally, very fine networks of this tissue run all through most of the organs, like the veins or ribs through the leaf of a plant, and support and unite their parts. If you watch the cook cut up a piece of suet, you will see the stringy connective tissue which penetrates it in all directions, and which must be removed from the fat because it will not melt in cooking.

5, Action of Alcohol upon Connective Tissue. — All intoxicating liquors, such as wine, brandy, whiskey, beer, etc., contain alcohol and are known as alcoholic drinks. One very serious change in the body frequently produced by drinking such, is an excessive growth of the connective-tissue networks, especially in the liver and the kidneys. The tissue becoming too abundant crushes and slowly destroys the chief liver and kidney substance which it was meant to protect and support. The results are incurable diseases. (See pp. 132, 189.)

6. The Bony Skeleton (Fig. 3), like the body itself, may be described as consisting of head, neck, trunk, and

5. What are alcoholic drinks ? How do they affect connective tissue?

6. Of what parts does the bony skeleton consist ?

THE SKELETON-.

Fig. 3. — The bony skeleton. <z, h^ the skull; r, ^, the back-bone; d, the breast-bone; «, the collar-bone; /", the humerus; y, the ulna; g^ the radius; h^ the carpal bones; z, the metacarpal bones; k^ the phalanges of the fingers; j, the hip-bone; r, the thigh-bone; g, the knee-pan; /. the shin-bone or tibia; m, the fibula; «, the tarsal bones; o^ the metatarsal bones; /, the phalanges of the toes.

i6

THE BACK-BONE, limbs. Its central part, which bears all the rest, is a stout, bony pillar, the back-bone^ c, e, on the top of which is the skull.

7. The Back-Bone, Vertebral Column, or Spine, is represented in side view in Fig. 4. Its upper part is made of twenty-four short thick bones piled one upon another, and each called a vertebra. Between each pair of vertebrae there is placed during life an elastic cartilaginous cushion. The lower part of the spine consists of two bones; a large one, the sacrum^ extending from S\ to Co\\ and a much smaller, the coccyx^ reaching from Coi to the end.

Projecting from the back of each vertebra (to the right in the figure) is a bony bar, called its spinous process. Through the skin .along the middle of the back we can feel the tips of these processes, and it is their presence which has given the name spinal column to the whole.

A canal runs through the whole back- FiG. 4. — The spinal bouc cxccpt the coccyx_, and opens into

column viewed from the , 1 ^ 1 1 1 1 t • 1

leftside. C1-7, the ver- the skull-chambcr above. It IS the

tebraeof the neck; Z>i-i2, . .

the vertebrae behind the loWCr part of the dorsal CavitV (a, FiOf. I ),

thorax. Z1-5, the verte- ^ ^ \ > t> /'

brae of the loins; ^^i to and, as wc havc already learned, con-

O71, the sacrum; Cox-^^ "^

the coccyx. tains the spinal cord.

7. What other names has the back-bone? Divisions of its upper part ? Lower pari ? What is the spinous process ? The dorsal cavity ?

USES OF BACK-BONE.

i;

8. Uses of the Mode of Structure of the Spinal Column. —

The elastic cushions between the vertebrae make the whole column springy and prevent the transmission of sudden jars along it. By this means the soft brain, carried in the skull on its top, and the spinal cord lying in

Fig. s. — The skeleton of the thorax, with some of the vertebrae of the neck and loins. ^, lower neck vertebrae; b^ the first rib; c, the collar-bone; d^ third rib; e, seventh rib; ^, last loin-vertebra; h^ the breast-bone; /, the shoulder-blade.

it, are protected from injury in running and jumping. These cushions also allow of a little bending between each pair of vertebrae, so that the spine as a whole may be bent a good deal. But no sharp bend, such as would nip the spinal cord, which lies inside it, can take place