Pennie Leibersperger, age 14, of Allentown, Penn., for her question:
WHAT VALUE DOES HAIR HAVE?
When some animals are startled, muscles make the hair move away from the skin and almost stand on end. The same thing happens when the animal is cold, with the extended hair trapping warm air. The startled animal is made to look larger and more dangerous than he really is. In addition to using hair for protection and warmth, some animals use it for sensation
Hair is found on certain parts of the bodies of most mammals. It grows on only limited parts of the body in man while completely covering animals as dogs and sheep.Hair can also be called fur, fleece, bristles and quills.
Thick hair that covers most mammals keeps them warm by acting as insulation. In cold weather, hair actually keeps warm air near the body for better insulation.
Hair can also help protect an animal's body. A thick pelt can absorb some of the shock when a falling branch or sliding rock hits an animal. And a seal's flat hair shields the animal as he pulls himself over sharp stones.
Thin clumps of hairs in ears and noses also offer protection. These strands catch many particles that would otherwise enter these organs.
Many animals have tactile hairs, or whiskers. These on many animals are especially sensitive and are often found on lips, cheeks, elbows, flanks and above the eyes. They help an animal feel his way through narrow places or in dark areas.
A tactile hair is especially sensitive to touch because the area around its base is richly supplied with nerve endings that respond to touch. Man does not have any tactile hairs.
Hair is made of the same material that is used to form nails, claws, hoofs, scales and feathers. Each individual hair is made up of a root and a shaft. The root and a small
section of the shaft lie below the surface of the skin in a sac called the follicle.
At the bottom of a hair's follicle is a projection called the papilla. Here you'll find an artery that nourishes the root of the hair.
The outside of a hair shaft is called the cuticle. Beneath the cuticle lies the cortex, a layer of tightly¬packed cigar shaped cells.
If you were to study hair under a microscope, you'd find it varied in shape from flat to round. Flattened hair shafts tend to grow at unequal rates in different places, making the hair curl or wave. The flatter a hair appears under a microscope, the wavier or curlier it will be. Straight hair has a round shape.