Part 10 (1/2)

4. How may the muscles be named?

5. Tell about the muscles of the head, trunk, and limbs.

6. Which muscles are the weakest, and which are the strongest?

7. What is necessary if you would have strong and healthy muscles?

CLa.s.sES AND WORK OF THE MUSCLES.

The muscles are divided into two great cla.s.ses: those which we may move as we choose, called _voluntary_ muscles, and those over which we have no power, called _involuntary_ muscles.

Some muscles support and move the various parts of the body, others have different work to do. The heart, the great involuntary muscle, acts like an engine to drive the blood throughout the body; the lungs draw in and throw out the air in breathing; the stomach helps to churn and change food into blood; the tongue is used in speaking and eating.

QUESTIONS ON THE MUSCLES.

What are the muscles?--”The lean flesh of the body; bands and bundles of fleshy threads which cover the body.”

Of what use are the muscles to the body?--”They cover the bones; they support and move the bones and different parts of the body.”

Name some parts of the body which are made of muscles.--”The eyeb.a.l.l.s, the eyelids, the tongue, the heart, the lungs.”

What color are the muscles?--”Red.”

How do the muscles move the bones?--”By shortening or lengthening themselves according to the way the bones are to be moved.”

Tell how the muscles move your arm at the elbow.--”The muscles in the front part of the arm shorten themselves, to draw my fore-arm toward the shoulder; when I wish to stretch out the fore-arm these muscles lengthen, while another set of muscles shorten, to draw the fore-arm away from the upper arm.”

What do you say about the muscles because they have the power to shorten and lengthen themselves?--”They are elastic.”

About how many muscles are there in your whole body?--”About four hundred and fifty.”

How may these be divided as you study about them?--”They may be divided into the muscles of my head, the muscles of my trunk, and the muscles of my limbs.”

Of what use are the muscles of your head?--”They cover and move the parts of my head and face.”

Of what use are the muscles of your trunk?--”They move the parts of my neck and trunk.”

Of what use are the muscles of your limbs?--”They move the parts of my arms and legs.”

How can you make your muscles strong?--”By using them.”

How can you make your muscles weak?--”By not using them.”

What is necessary to make your muscles strong and healthy?--”They must be used; they must be rested when tired; they must be supplied with pure blood.”