How does the body keep itself working properly?

Millions of chemical reactions take place in the body, and because they can influence one another, they all need to be kept in balance. This process is called homeostasis, and it ensures...

About Salvador Dali

Salvador Dali (1904-1989) was a Spanish painter. In 1928 he collaborated with Bunuel on the film Un chien andalou. In 1929 he joined the Surrealists and became notorious for his...

What happens in the small intestine?

Most of the process of digestion takes place in the small intestine. Food is broken down into simple substances that can be absorbed through the gut wall into the blood. Most of these...

How do I swallow food?

Swallowing is a complicated muscular process. Your tongue forces food to the back of your mouth and into the throat. At the same time the soft part of the roof of your mouth closes...

Why do I have different types of teeth?

Teeth have different shapes so they can carry out different jobs. Incisor teeth at the front of the mouth are flat and shaped like chisels. You use them to cut your food. The canines...

Why do I need food?

Your body is built and maintained by substances that you obtain from your food. These substances are broken down and absorbed into the body during the process digestion. They are then...

What is circulation?

Blood is pumped continuously around the body's circulatory system. It is pumped in a continuous flow from the heart through the arteries, then through the tiny capillaries and back...

How does the heart work?

The heart is a fist-sized muscular organ that pumps blood around the body. It is actually two pumps that are joined together. At the top of each side of the heart is a thin-walled chamber...

What is blood?

Blood contains red and white blood cells that float inside a liquid called plasma. It also contains thousands of different substances needed by the body. Blood carries all these things...

How do I breathe?

When you breathe, you draw air in through the nose and mouth and into the lungs. Air consists of 79 percent nitrogen and about 21 percent oxygen, with small amounts of carbon dioxide...

What job do muscles do?

Muscles are needed for all body movements. Muscles move the bones, julling them into position as they move about their joints. Some muscles just move soft parts of the body, for example...

Why do I need a skeleton?

Bones provide the framework that holds the whole body together. Without a skeleton you would simply flop about, and you would not be able to move.The skeleton also gives protection...

What is metabolism?

Metabolism is the term for all of the chemical activity that takes place inside the cells. Metabolism breaks down more complicated substances obtained from food. This allows these...

What are organs?

Organs are made up from different types of tissue that are grouped together to carry out a particular body function. The heart, for example, is a collection of muscle tissue, connective...

What's inside a cell?

Cells consist mostly of a watery jelly-like material called cytoplasm. Each cell is held together by a very thin flexible membrane, rather like a balloon filled with water. Inside the...

The Human Body

It is easy to take our own bodies for granted. We feed ourselves, keep ourselves clean and warm and are reasonably careful to avoid injury, but otherwise we don't think about how our...

Human Evolution

Homo erectus was the first of our ancestors to walk completely upright, and he looked very like modern man, though with a heavy jaw and bony eyebrow ridges. Homo habilis was an...

About Marie Curie

Marie Curie (1867-1934) was a Polish scientist, who investigated radioactivity, and with her husband Pierre (1859-1906) discovered radium. Born in Warsaw, she studied in Paris from...

Where did humans probably evolve?

The early ancestors of humans were called hominids, and they appear to have evolved in Africa where many of their remains have been discovered. The earliest remains of what were...

Who were our first ancestors?

Humans belong to a group of mammals called primates. It includes apes, monkeys and several much smaller animals such as lemurs and bush babies. As much as 50 million years ago, back...

Could a giant sauropod walk on its front legs?

Some fossil footprints of Apatosaurus caused puzzlement when scientists realized that they were the imprints of only the front legs of this vast reptile. They realized that the...

Where are most dinosaurs discovered?

Most fossils have been found in Europe and North America, but they have also been found in most other parts of the world. In recent years, huge numbers of new and exciting fossils...

How are dinosaurs preserved and reconstructed?

It is rare that you can just pick up dinosaur bones. They are usually embedded in very hard rock, and it can take weeks of painstaking work to chip them out carefully and release the...

Why do palaeontologists disagree about dinosaurs?

Scientists have found very few examples of some of the more interesting and puzzling types of dinosaur. It is very rare to find a complete skeleton, and even rarer to find other clues...