Your Body

Although onions taste really delicious on hamburgers or in a stew, the person cutting and cooking them usually sheds a great many tears first. This happens because onions contain a strong smelling oil. When the onion is peeled and cut, this oil escapes into the air in the form of vapor, or tiny particles of […]

When you are asleep and relaxed, and breathing through your mouth rather than through your nose, the air coming out causes your soft palate, the tissue at the back and top of your mouth, to flutter back and forth. This fluttering, or vibration, makes a sound called a snore. Often this vibration causes the cheeks, […]

Your sense of smell is very closely related to your sense of taste. To see how this works, think of a chocolate ice cream cone at your lips. You taste the sweetness of the chocolate with the taste buds at the tip of your tongue. But the smell of the chocolate is a job for […]

The inside of your nose is like a chemical laboratory for smelling. It has the power to smell even extremely small amounts of an odor. Odors are actually tiny particles, or molecules, of gas that travel through the air and into your nose. In the highest part of your nose, these molecules touch a group […]

Because your tongue is made up of muscles which you can control, it helps you chew and swallow your food. These muscles run in many directions so you can move the front part of your tongue in many different ways. Your tongue can push food between your teeth, move it about from side to side, […]

Look in the mirror and stick out your tongue. See the little bumps on the surface of it? Inside each of these little bumps, or papillae, are about a dozen tiny organs called taste buds. There are also taste buds in three places in your throat. Not all tastes are detected by the same taste […]

Your brain contains memory centers where millions of old memories are stored away in an orderly manner according to subjects: music you have heard, sights you have seen and tastes and smells you have experienced. Because of this orderly arrangement, it is possible for one section of a person’s brain to be damaged or destroyed […]

It is not the size of the brain that makes one person brilliant and another backward, for most adults have the same size brain about three pounds. Rather, it is the way the brain develops. Your brain stores information from your past experiences, helping you to remember, learn, and think. But people differ in how […]

A computer is a complicated electronic or mechanical machine invented by man to solve difficult problems. But a computer can only carry out instructions that the human brain gives it. The computer has no ability to think or reason for itself. However, it could take a man a lifetime to solve some of the problems […]

When you are lightly touched on any part of your body, nerve cells inside your skin respond to that touch and send a message to your brain. Your brain can receive that message in two different ways. If it receives a “tickle message” and decides that the tickle should be scratched, it will send a […]

Valentine hearts come in all sizes, but a real heart, the one inside the human body, doesn’t look anything like them. Make a fist with your hand. That’s about the size and shape of your heart. Your heart is not very large, but it is very important, for it keeps you alive by pumping blood […]

Anyone who has ever hurt his “funny bone” knows that there is nothing funny about this bone at all. In fact, this “bone” is not really a bone at all; it is actually a nerve located at the back of your elbow above your bone and near the surface of your skin. When you hit […]

When you are breathing normally, your diaphragm, a large, powerful muscle in your chest, tightens and relaxes to pull in the air and push it out. However, when organs near your diaphragm become irritated, they cause the diaphragm to contract suddenly in a kind of spasm as it takes in a breath of air. At […]

In some cases, yes. The Indians of the Andes Mountains, on the west coast of South America, have developed bodies which are different from ours in order to survive where they live. At 17,000 feet above sea level, where these Indians live, we would find it very hard to breathe, but they do not. The […]

There were two special chromosomes in you when you were just beginning life as a fertilized egg. These are called sex chromosomes. Scientist have named them the X chromosome and Y chromosome. A woman’s egg cell contains only an X chromosome, while a man’s sperm cell Y contains either an X or a Y. If […]

Every parent, human, animal, or plant, passes down certain characteristics to their children so that these offspring will resemble them, but not be exactly like them. This passing down of characteristics is called heredity. When you began life as an egg produced by your mother and fertilized by your father, you came with a pre-packaged […]

When you eat, your food is broken down and sent to the cells of your body. These cells take in the food and grow bigger. Then each cell divides and becomes two cells exactly like itself. Each cell divides again, making four cells, and so on. This cell division goes on day and night. As […]

About nine months before you were born, you started to grow from just two cells. One cell, a sperm cell, came from your father. The other cell, an egg cell, came from your mother. These two cells joined together inside your mother’s body and formed a new cell called a fertilized egg. This cell was […]

When you feel hot or cold, you are actually feeling the temperature of your blood. Since you are considered a warm-blooded animal (along with birds and other mammals), your body maintains an average temperature of 98.6° Fahrenheit (37.0° Celsius), no matter what the temperature is around you. Each species of warm-blooded animals has its own […]

Everyone’s blood isn’t exactly the same, but this important fact was not known to scientists until 1900. Before then, blood transfusions were given from person to person without any thought to blood types. When it was discovered that in about half the cases, the patient got worse after a transfusion, and sometimes even died, scientists […]

When you cut yourself, blood flows out of the wound. That blood contains, in addition to red blood cells and white blood cells, tiny structures called platelets. These platelets pile up around the wound, then combine with other substances in the blood plasma (liquid) and chemicals in the damaged tissue to form long sticky threads […]

Your blood has special cells in it that fight disease and infections. These cells, called white blood cells, are produced in your bone marrow, the, soft tissue that fills the inside of your bones. White blood cells work like an army to attack and kill harmful germs that get into your body. When an infection […]

Blood looks as if it is solid red, but it really is not. If you look at blood under a microscope, you will see that it is made up of four different parts: plasma, red blood cells, white blood cells, and platelets. The plasma, which is the actual fluid, is a yellowish-white liquid. It contains […]

Your heart is a kind of pump which sends blood to all parts of your body, since none of your cells can work or grow without it. Blood has three main functions: it carries food and oxygen to permit your body’s cells to work and grow; it carries wastes from these cells to organs which […]

The amount of blood in a person’s body depends on how big he or she is, and surprisingly enough, on where that person lives. For example, if you weigh about 80 pounds, you have about 2.5 quarts of blood in your body, while your 160-pound father has about five quarts, or twice as much. When […]

The billions of cells whose job it is to keep your body informed of conditions outside and inside it are called nerve cells, or neurons. Neurons transmit messages throughout the body by passing signals, or impulses, from one to the other. Sensory neurons are nerve cells which carry impulses from the eyes, ears, nose, mouth, […]

All living things on earth, plants or animals, have one thing in common they are all made up of cells. Your entire body, your bones, your muscles, your skin, your blood, your teeth, your nerves, your hair, contains more than 10 million million (10,000,000,000,000) cells! Most of these cells are so tiny that you can […]