Brain
From the Simple English Wikipedia, the free encyclopedia that anyone can change
The brain is a part of the body that allows us to make sense of the world around us and to change our behavior to respond to it. In most animals, the brain is inside the head. The brain is kept safe by the skull and by layers of tissue under it called the meninges.
Contents |
[change] Jobs
The brain does the thinking, learning, and feeling for the body. It is the source of consciousness, but it also controls basic body functions, like breathing, that happen without a person realizing it. All the information about the world gathered by our five senses is sent through nerves into the brain, allowing us to see, hear, smell, taste and feel things. The brain processes this information so that we can experience it as pictures, sounds, and so on. The brain also uses nerves to tell the body what to do, for example by telling muscles to move or our heart to beat faster. It is believed that the full power of the brain is yet to be obtained due to the fact that we only use a small percentage of our brain.
[change] Parts
In human beings, the brain is made of three main parts: the cerebrum, the cerebellum and the brainstem. A human brain accounts for about 2% of the body's weight, but it uses about 20% of its energy. It has about 50-100 billion nerve cells (also called neurons), along with at least 10 times as many support cells, called glia. The job of neurons is to receive and send information to and from the rest of the body, while glia provide nutrients and guide blood flow to the neurons, allowing them to do their job. Each nerve cell has contact with as many as 10,000 other nerve cells through connections called synapses.
[change] Size
The volume of the human brain (relative to the size of the whole body) is very large, compared to that of most other animals. The human brain also has a very large surface (called cortex) for its size, which is possible because it is very wrinkled. If the human cortex were flattened, it would be close to a square meter in area. Some other animals also have very wrinkled brains, such as dolphins and elephants. Some people believe that what makes humans so smart is the large volume or surface area of their brains, but there is no evidence for a relationship among animals between size of the brain and intelligence; e.g. the brain of a blue whale is much heavier than a human brain, but it is not seen as being more intelligent than a human's brain. As an additional note, Einstein's brain weighed about two ounces less than the average human brain.
[change] Other websites
- Sylvius: 400+ structure neuroanatomical visual glossary; used by over half of U.S. medical schools
- High-Resolution Cytoarchitectural Primate Brain Atlases
- Human Brains: A Learning Tool.
See also: Spinal cord
