Physiology for beginners

Front matter

Med

Coll.

welMOmec

Appendix

Lessons for Review

Words Pronounced and Defined .

INDEX .

’03

How Girls Carry Books : Forward on the hip. This may twist the spine and make shoulder too high on that side. Boys carry books under one arm with shoulder on that side too low. Compare heights of your shoulders after method of fig. 13, p. 23.

Correction of Posix're by dividing the load. Another way is to change to other arm at end of each block, or on every other day. (From Bancroft’s " The Posture of School Children,” a useful book for teachers.)

Girls Upward Stretching, to straighten themselves, but not knowing h:.w.

Upward Stretching, to improve posture, after the teacher has shown the right way.

A Group of Well-poised Boys. Their houses will not have crooked frames. Bodies kept straight Until i6 years old remain straight. Bodies that beenme crooked in youth usually stay crooked.

Chapter I

A Beautiful House. — A man who wrote a book about the body called it “ The House I Live In”; another writer has called it “ The House Beautiful.” In these books the body was compared to a house, and parts of it were named from the parts of a house, as the framework, the pantry, the door, the hall, and the windows. Can you tell your teacher what was meant by the door, the hall, and the other parts mentioned ? But who ever heard of a house that was alive and walked !

A Curious Custom. — In England sometimes poor people who are able to build only very small houses, go from village to village to work or to peddle, by placing their houses on wheels, and moving them with horses. Thus they travel around the country, eating and sleeping in their houses. Sometimes they have a little shop in one end of the house, where the man cobbles shoes or sells and mends tinware or gives Punch and Judy shows. Such a house is called a van.

Van is a short word, but you may never have

.19 heard it because we have no such vans in America.

The roads here are usually not so smooth and well paved as in England, and the towns are not so close together.

Would you like to see a van moving along with the smoke going out through a little stovepipe

Jolts and Jars. — Vans must have good strong frames, for they are more likely to fall to pieces than the house which remains in one place. So this wonderful house in which we live must be built well, for it moves quickly from place to place. It has a strong and perfect framework called the skeleton.

The backbone, or spine, is the main pillar or column that supports the building. Although called a bone, the backbone is not one bone, but a number of bones put one on top of the other, forming a tall pile. Between the bones Fig, r.— The Backbone, are little pads of gristle, which are Can you count th. bone, elastic, tliougli not SO elastic as

pli's ,rpS.'Sf rubber. They help to lessen the force of any shock or jar, just as the springs of a carriage lessen the jolting.

M

1..23

THE SKELETOH

The master of the house lives in a room called the skull, situated on top of the main pillar. It is not square, like most rooms, but round. If there were sharp corners, the walls would be more likely to be injured. The walls are firm and stout. The two windows through which the master looks are placed in front and high up in the wall, so that he can see a great distance. That these delicate windows may not be easily injured, the bones forming the brow, the nose, and the cheek stand forward around them. The nose, which tests the odors of things that come into this beautiful dwelling, is conveniently placed just above the mouth, or doorway. Before you study much about this house, perhaps you will conclude that it is not only the most beautiful and convenient, but also the most wonderful house to be found in the whole world.

There are only two more rooms in the house, and they are in the large part called the trunk. The two rooms, or cavities, are called the chest and the abdomen (ab-do'men). The chest contains a perfect pump called the heart, and a pair of large bellows, called the lungs, for bringing in fresh air and sending out impure air. The lungs and the heart are very delicate. They are protected by twenty-four flat ribs, which curve from the spine around the chest somewhat like the hoops of a barrel, and unite in front with the breast bone. The abdomen is just below the chest, and is separated from it by a fleshy partition. It contains the stomach, liver, intestines, and several other important organs. The organs are supported from beneath by two large bones called hip bones. These bones form a kind of basin (Fig. 5), the edge of which can be felt at the hips.

The shoulder and arm are as well arranged as the rest of the body. In order that the arm may be held out from the trunk and have greater freedom of motion, it is not joined directly to the trunk, but to the shoulder. The shoulder blade is a broad, three-sided bone. At one end is a shallow cavity, into which the round head of the arm bone fits. The shoulder blade would not stand out alone from the trunk, so the collar bone acts as a brace to hold it in position. You can feel the collar bones above the chest like slender crossbeams running from the breast bone to the shoulder blades. Move the shoulder up and down. Does the collar bone move up and down .? Put your right hand on your left shoulder. Does the shoulder blade move } The collar bone is sometimes broken by falling heavily on the shoulder. Boys who are reckless climbers have broken it in this way by falling from trees. After the collar bone is broken the shoulder falls forward, as there is nothing to keep it in position. A broken bone in a boy heals in about six weeks.

A joint is a place where two bones are joined together. There are several kinds of joints in the body, each allowing a different kind of motion. The shoulder joint is called a ball and socket joint because the round end of the arm bone fits into a socket on the shoulder blade. At the shoulder joint you can move the arm up and down, backward

THE SKELETOIV and forward, and in all directions. A ball and socket joint allows motion in all directions. (Fig. 6., The arm is divided into the upper arm, forearm, and hand. The upper arm has only one bone. (See Fig. 2.) The forearm has two bones. One of them turns around the other, thus allowing the hand to be turned over; this is a great convenience in using the hand. (Try turning the hand ; will it go all the way around, or only half around?)

To the forearm is joined the wrist, which is made up of eight little bones, shaped somewhat like blocks and fitted together like the bricks in the pavement.

Since they glide over one another as the wrist bends, these joints are called gliding joints. See how smooth and curved the wrist is when it is bent. This is because there are several joints instead of one. (Fig. 7.)

Fig. 2. — The Skeleton.

You see by the picture that the fingers appear to extend to the wrist. This is because the palm is made up of five bones shaped like those of the fingers. In the skeleton hand the difference between i6 the fingers and the palm is not noticeable. Which could you better afford to lose by accident, a thumb or a finger.? A thumb or two fingers ? Could you do more with the thumb and forefinger than you could do with all of the fingers without the thumb.? Why is the thumb so much more useful than any one of the fingers .? What kind of people talk with their fingers .? Did you ever hear of any one who could read with his fingers.?

The legs have the same number of bones as the arms. There is no bone in the arm corresponding to the knee cap at the knee. There is, however, one bone less in the ankle than in the wrist, so the numbers are equal. The upper bone of the leg. is called the thigh bone. It is the largest and strongest bone in the body. It is so large and heavy that the warriors of savage tribes sometimes carry as weapons the thigh bones of slain enemies. The thigh bone joins the two bones of the lower leg at the knee. (See Fig. 2.) The knee cap is a flat, round bone that protects the knee joint from injur}^ If you straighten your leg and rest the foot upon the floor, you can move the knee cap with your hand. Can you move it from side to side or up and down ?

The two bones of the lower leg are the shin bone and the splint bone. The splint bone is very slender. The surface of the shin bone can be felt just under the skin. Can you feel it all the way from the knee to the ankle ?

The seven ankle bones are not so regular as those

^7

Fig. 3. — A Vertebra.

One of the bones of the spinal column.

in the wrist, and one of them, the heel bone, is nearly as large as the other six together. The bones of the ball of the foot correspond to those of the palm, and the bones of the toes to those of the fingers.

Which toe has only two joints .?

The bones of the foot taken together form an arch, so that the middle of the foot hardly rests upon the ground. Upon this firm but springy arch the weight of the whole body is thrown at every step, without shaking or jarring the other bones or the delicate organs. (Fig. 9.)

The Joints. — The pieces in the framework of the van, or the little house on wheels, are fastened firmly together, so that not one piece of the framework can get out of place. Most of the parts in our skeletons, or framework, are joined together in such

a way as to allow motion. Can you state what a joint is .? We have over two hundred bones in our frame. All the joints are movable except those in the hips and the skull.

The Joints of the Skull. — The round bony case called the skull, which holds the delicate brain and protects it from injury, is made of eight bones beautifully fitted together. Look at the picture (Fig. 10), and you will see how the bones are put

Fig. 4. — The Skull.

i8 together at the top of the head and how their edges are notched. 1 hey fit into one another like the

notches at the corners of a chalk box, but the notches in the bones are not all of the same size and shape. The skeleton has immovable joints where delicate organs are to be protected, and movable joints where motion is necessary. Which bone of the head is fastened by a movable joint ? Why are most of its joints immovable?

Try to pick up a pencil from the desk without bending a joint of the Fig. s.— The Bones of hands. YoU SCC how hclplcSS yOU the Trunk. would bc wcrc the joints immov-

The upper room has ribs , i t • , , i .

of bone in its walls, able. JOintS that

The lower room has ^HoW mOVCmCnt walls of muscle.

back and forth like a door are called hinged joints. Can you tell why they are called hinged joints? A straight rounded ridge on the end of one bone fits into a groove in the end of the other. The elbow joint does not allow so free movement to the forearm as the shoulder joint allows to the whole arm. Describe the motion of the elbow joint.

What joint in the leg is like it ?

The leg can swing outward at the hip as well as backward and forward. You learned when study-

Fig. 6. — The Two Bones of the Shoulder, and the Ball on the Bone of the Arm fitting into a Hollow in the Shoulder Blade.

ing the arm that a joint which, like the shoulder and hip, allows motion in all directions, is called a ball and socket joint. (See Fig. 6.) It allows motion in all directions because one bone has a round ball-like end which fits into a cuplike cavity, called a socket, in the other bone. Which joint allows freer motion, the shoulder joint or the hip joint .? Why are you glad that it is so ? The bones at the hip are separated, or dislocated as it is called, less easily than the shoulder joint; this is because the socket is deeper.

Some joints allow motion somewhat like a wheel turning on an axle or a

Fig. 7.

How many bones are in each finger? in the skeleton of the hand, why does each finger appear to have an extra joint ?

top turning on its point. Such joints are called

pivot joints. The forearm allows the hand to turn in this way.

This is because one of the bones of the forearm turns over the other, its upper end being fastened at the elbow, the bone turning like a wheel on a pivot.

There is only one more pivot

Fig. 8. — The Hand of a . . . , ^ ,

Monkey, holding to a jomt in the frame besides those

in the forearms. Can you find

How does it differ from a Ii. ;» man's hand ?

You learned when studying the bones of the wrist that they glide over one another and form what are called gliding joints.

Fig. 9. — Bones of the Foot.

Can you now name the four kinds of movable joints and give an example of each? What kind of joint is found in the fingers? Name the four ball and

socket joints. What kind of joints do you think is most numerous in the body?

The joints of the spine are hard to classify. One bone does not move over another, as in the movable joints, yet as they allow a little motion, these joints cannot be called immovable. This motion is possible because the pads of gristle, or cartilage, between the bones can be squeezed together a little at one side and stretched a little at the other. If sitting or standing, you bend too far forward, the cartilages become V-shaped and the spine is rounded backward.

If you write at too high a desk or always carry schoolbooks and other things in the same hand, the spine may, in time, become bent to one side. Such joints are sometimes called mixed joints.

You did not know that you are taller in the morning than you are at night. The weight of the body during the day compresses the pads of cartilage in

Fig. 10. — Top View of the Skull, showing Immovable Joints.

the spine ; but when you lie down during the night they regain their usual size. Early in the morning let some one tack a strip ot wood to a post so that the strip just touches the top of your head. Stand under it again in the evening. Does your head still touch it.?

The ribs that join the breast bone are fastened by one cartilage, just as the bones of the spine are fastened to one another. (See Fig. 5.)

The immovable joints (where are they found?) have no cartilages in them. The mixed joints have one cartilage each. The movable joints have two cartilages, one on each bone, so that the surfaces of the bone do not rub together, but the smooth, white cartilages rub together instead. If the hard bones in the movable joints touched one another, a sudden jar might break them. The layer of tough gristle or cartilage over the ends of the bones prevents this. Cartilage is not brittle like bones. Would you like to feel cartilage.? Then you may feel your ear. It is all cartilage except the skin which covers it and the fat that is in the little lobe at the bottom. Is cartilage tough ? Does it bend . Is it elastic.? Is it hard or soft? Did you ever see the shiny white cartilage on the end of a fresh bone as the bone of a fowl ? Dry bones have lost their cartilage.

Something besides cartilage is necessary for a joint. Suppose you put two bones together that belong together. See how readily they fall apart. To keep the bones together, the joints are provided

Flo. II. — The Topmost Vertebra showing the Two Sockets in which the Skull rests, and the Hole for the Peg of the Second Vertebra, with stout bands or cords called ligaments, which fasten the bones together. They are very strong.

Children sometimes make the joints of the fingers crack. This should not be done, as the joints are

weakened by stretching the ligaments. The bones of the joints move noiselessly. This is because there is in the joint a slimy liquid, like the white of an egg. Did you ever see this liquid when the joint of a fowl or a soup bone was being disjointed in the kitchen ? One of the bands or ligaments is like a collar, and keeps this slimy fluid in the joint. The more you use the joint, the faster the liquid is formed, so there is always just as much as is needed. Did you ever hear of machinery that oiled itself.? Suppose some one should make you a present of a beautiful sewing machine or a bicycle. Would you not take great care of it? We should take even greater care of the perfect body given us, so that it may remain perfect in form and grow strong and heal thy.

Are you becoming “round-shouldered ” or flat-chested ? If it takes you two years to become round-shouldered because of carelessness in sitting and standing, how long will it require with care for you to regain a correct shape? If you put

Fig. 12. — Second Vertebra showing the Peg for the Pivot Joint with the First Vertebra.

poisons, like alcohol and tobacco, into the body, they may prevent the bones from growing to full size and becoming sound and strong. Do you know of any boys who have smoked cigarettes for several years ? Are they as strong and large for their ages as other boys.? Are they rosy-cheeked and healthy? Did you ever know a father who advised his son to use tobacco, even though he used it himself? Fresh air and sunlight, work and play, are good for the bones.

The rule for sitting : '

Sit as far back in the seat as you can. Never allow yourself to slide forward in the chair.

The rule for standing : Head up, chin in, chest forward, hips back. This is also the right position for walking.

A sprain means that a ligament has been stretched and partly torn, or that one of its ends has been torn partly or wholly from the bone. It is sometimes more serious and harder to recover from than a broken bone. Rest and patience are needed while the parts are growing together again. Proper care of our bodies is always wise. Who more often have sprained ankles, boys or girls ? Who w^ear broader heels to their shoes ? Who take more exercise ?

Fig. 13. — This boy was told by his teacher that he was nearly a half inch lower at night than in the morning. He could hardly believe it, and he is tacking a strip so that it just touches the top of his sister’s head. He mav be surprised when she stands under it again at night.

— C Marrow.

Compact 'A or dense tissue

A dislocation means that a bone is out of its place at the joint. The bones of the spine are sometimes slightly dislocated when a rude or thoughtless child withdraws a chair from some one who is about to sit down.

If a baseball bat is broken, you repair the break by wrapping wire around it. If a pitcher is broken, you may glue it together. But a broken bone heals itself if the broken ends are placed in proper position. It must be kept in place with splints until it heals. The healing usually takes five or six weeks, but the bone is weak for a still longer time; a person with a broken bone should be careful for several months. After it is firmly healed it is so strong that the bone is just as likely to break again at another point as in the same place. If the wire is taken from the bat, the Fig. 14. — A Hollow pieces come apart, showing that Bone. The femur, or broken pieces have not united

large bone of thigh, ^ ^

showing two kinds of like a broken bone.

tissue and the marrow jg WOnderful and

cavity. Which end J

forms a ball and socket Convenient than any house. W ith joint? A hinge joint?

keeps itself in order. The bone, in life, is covered with a tough coat through which blood vessels enter

^5 and carry the blood that enables the bone to repair itself. When bones of a drunkard or of a sickly person are broken, more time is required for them to unite than for those of a well or a temperate person.

When a bone is healing, at the end of the first two weeks the new bone that is forming is only a kind of jelly. The harder part, called the mineral matter, is deposited later.

Bones are composed of two kinds of matter, — the animal matter, which is like gelatine and glue, and the mineral matter, which is somewhat like limestone. Why cannot a bone be destroyed by burning it ? Did you ever see a piece of bone which had been in a fire a long time ? Was it more or less brittle than before.? Was it lighter or heavier.?

The bones are two thirds mineral and one third animal matter, or gelatine. The animal matter can be removed by boiling or by burning. The animal matter, gelatine, remains in the water after the bones are taken out ; the water and gelatine after cooling take the form of the vessel. Glue is made of gelatine.

The mineral matter may be removed from a bone by soaking it in strong vinegar. Take a hog’s rib or the leg of a fowl and soak it for three days in very strong vinegar. You can then tie the bone in a knot! Your teacher may then wash the vinegar away and keep the bone in a bottle of glycerine, or in a bottle of alcohol and water. There is less mineral matter in young children’s bones than in the bones of older people. Why should babies not be urged to walk ? What deformity may result from walking too early ?

Since the bones of older people contain less animal matter they are more brittle than the bones of children. Why should young people help old persons over rough places ? What is the use of each of the kinds of matter found in bones

Can won name each animal whose skeleton is shown above ? Has every one of these animals a backbone ? Shoulder blades ? One bone in first joint of limbs ? Two bones in second joint of limbs ? Which ones have finger bones and toe bones ?

Chapter II

Questions you can hardly Answer. — “ Why do you become hungry every few hours, eat food, and drink water ? What is food ? Why are some things ‘good to eat,' and others poisonous? What happens to the food that you swallow? Why does a man become thin and weak if starved, or poorly fed? How is it that your body is always warm not only in summer time, but on the coldest winter days ? Why do you feel hot when you run ? why do you then pant for breath and why does perspiration make your skin quite wet? Why does your chest rise and fall about sixteen times a minute ? Why do you breathe in air and then ‘puff it out’ with the help of these movements? Why do you choke if you grasp tightly the front of your neck with your hand and why does a man soon become choked if shut up in an air-tight box ? Of what is the blood, which you see whenever you cut yourself, composed ? What is the heart doing when you feel it beating against the left side of your chest ? What is the pulse which you can feel throbbing in your wrist ? How do the eyes see, the ears hear, the tongue taste, the nose smell, and the skin feel? Lastly, how is it that you can move the parts of your body, walk, run, and train your hands to skilled uses ? ”

The Science that Answers these Questions. — These were the questions put by a teacher of physiology in England to a class beginning the study. Arithmetic, grammar, and geography help us to answer many useful questions. Physiology helps us to answer questions like those above. I think you will agree that there is no more useful study than physiology. For, after studying it, you will probably be able to answer every one of the questions, although you cannot answer one of them now.

Physiology teaches us about ourselves, how we live, and how the parts of the body called organs, such as the bones, muscles, heart, and lungs, do their part in helping us to live. The special duty or work that each organ has to do is called its function. The science of health is called hygiene and it is founded upon physiology. In studying physiology and hygiene, we are learning how to keep healthy and how to regain health if it has been lost.

Many wonderful things also are learned in this study. Some of the most wonderful are about our moving and thinking. Suppose your teacher sa}^s “Fold your arms”; you know what to do because she told you.* But suppose the teacher says, “ You may each do something without my telling you.” How many different things would be done! Who told John to put out his tongue, or Mary to nod her head.? No one. The thought of doing so came from their own brains and there the actions started.

Fk3. 16. — The Brain, the Spinal Cord, the Nerves.

The Brain. — Can you describe a cow’s brain, or a hog’s brain, that you saw in the kitchen or at the meat market.? What can you say about the color of the outside? Of the deeper portions? Was it smooth or uneven ? Strange to say, such brains look very much like our brains, but they are not so large as ours. Some one has said that the many wrinkles and foldings of the outer gray part of a man’s brain look like the kernel of a hickory nut or a walnut.

The brain is the part of the body in which the mind works. It is here we think, and feel, and will.

It is to the body what the general is to the army, or the mayor is to the city.

The Chinese suppose that the soul is located in the stomach. We do not merely suppose, we know, from what men who study physiology have proved, that thinking and willing are carried on in the brain. But do not therefore conclude that there is no mystery about thinking and willing. There are many mysteries about our minds and our bodies ; we do not know what the mind is, or how it is connected with the brain. Physiologists have solved many questions, but there are many more that they, and all the other scientists, have failed to solve.

How the Brain controls the Body. — Suppose you are asked to tap your foot on the floor and you do How is it that the brain causes the foot to

Fig. 17. — A Well-developed Human Brain.

so move although at some distance from it? The answer will be given you at once, lest you may think that this book has too many puzzling questions. It has been found that there are small shiny white threads, called nerves, made of still finer threads, called nerve fibers, which connect the brain with every part of the body. The brain sends an impulse along the nerve fibers down to the muscles in the lower part of the leg. This impulse through the nerve fibers causes motion in the muscles, and thus the foot is moved and the toes tap upon the floor. The mayor of a town can send messages to the firemen, policemen, or scavengers in all parts of the town by means of the telephone wires. He can receive messages likewise, and so can the brain. If any one steps on your toe, the news is carried to the brain, which superintends the body, by means of the nerves. Where these nerves leave the brain, most of them are together in a big bundle called the spinal cord. Did )^ou ever see the marrow in the back bone of a hog? That was the hog’s spinal cord. How large was it ? A man’s spinal cord is somewhat larger than a lead pencil. Smaller nerves branch from it and connect it with every part of the body.