Structure of the Skin

 Perspiration

There are from 2 to 3 million sweat glands in the human body. They are most plentiful in the armpits, on the hands and feet, and on the forehead. These tiny coils extract water and some other substances such as salt and urea from the blood flowing through the capil­lary vessels in the true skin. The extracted water (i.e. sweat or perspiration! is then re­leased to the surface of the skin through the minute tubules or openings which we call body pores.

The quantity of perspiration released daily varies greatly and depends on many factors. The sweat glands are never entirely idle. The body, even though it does not feel wet, is con­stantly releasing some water through the skin. This so-called insensible perspiration may amount to a quart a day.

Loss of body heat through perspiration, both visible and invisible, involves not the blood vessels but the sweat glands. The per­spiration that exudes from the pores is re­moved from the surface of the skin by evapo­ration. A stream of warm, dry air speeds evaporation. That is why the warm breeze from an electric fan on a hot day still pro­duces the sensation of cooling.

Underneath the true skin is a layer of sub­cutaneous tissue which is usually largely in­filtrated with fatty tissue. This layer gives the body its more delicate curves and con­tours. It serves as a cushion between the tegumentary covering of the body and the underlying muscles and permits the free rip­pling of the skin during muscular activity.

The Functions of the Skin

The skin serves many vital functions for the body. It is, first of all, a protective covering, a barrier against the invasion of pathogenic bacteria. Second, it is the impor­tant regulator of body temperature and is provided with the mechanism with which to perform this task. Third it is an organ of sensation that provides warning against some of the threats to life or health, found in the im­mediate external environment.

 Fourth, it concerns itself with those reactions which heighten the body's immunity to disease. And, finally, it is an organ of expression, a mirror if you will, of many disorders, both Infection and psychic, which may affect the body.

Bacterial resistance on the part of the skin is high. This applies also to the mucous mem­branes of the lips, mouth, and other parts of the body. So long as the skin is clean, it very quickly gets rid of unwelcome bacteria that may come to lodge upon it. The mechanism of this repellent action is not altogether clear. Unless the skin is cut, broken, punctured (as by an insect), or abraded, harmful bacteria have a difficult time getting through its horny layer. Of course some bacteria always lie on the surface of the skin, just as some are al­ways to be found in the mouth.

Skin blemishes such as blackheads, pim­ples, sores, and scabs should not be picked at anywhere on the body, but this warning should be doubly observed concerning the area that is called "the danger triangle of the face." This area is bounded by the bridge of the nose and the corners of the mouth. Be­cause of the peculiar arrangement of veins and arteries feeding this area, bacterial in­fections originating here may be carried di­rectly into the brain and set up a possibly fatal inflammation.