The Brain

An organ of soft nerve tissue contained in the skull of vertebrates.

The brain is one of the most amazing parts of your body. Every day it allows us to do activities that we control and many that we don't. Our brain can help us:

• Read printed words
• Regulate our breathing
• Remember colors
• Manage the rhythm of our heart
• Control our body temperature
• Remind us to blink
• Remember how to play a game
• Ride a bike
• Determine what the soft fur on a dog's back feels like
• And many, many other things

It's true! Inside your skull your brain controls everything you do!!! It is more powerful and faster than any computer. Your brain is the most important part of you, and it is very complicated.

In the book, The Great Brain Book: An Inside Look At The Inside Of Your Head, author HP Newquist says, “Understanding the brain is one of the biggest challenges facing scientists. We're just now beginning to figure out how all the pieces of the brain work, but we have a long way to go. We still don't know how it creates thoughts or how it stores pictures in your head. It's not a photo album or a CD player that just files your favorite images and songs. It's a complicated organ that does billions of things every second that you're alive. That makes it the most powerful organ on earth.”

Your brain fills the upper part of your bony head, which is called the skull. The top part of the skull, called the cranium, is made of 8 bones. The rest of your skull includes 14 bones in the face and 3 small bones in each ear. How about that! Altogether, there are 28 bones in your skull, and your brain is tucked safely inside, protecting it from most minor bumps and blows. Learn more about the skull at this Neuroscience For Kids site.

Here are some interesting pieces of information about the brain:

• The brain is always working, even while you sleep.
• Your brain can go without oxygen for 3-5 minutes before injury will occur.
• Scientists aren't sure how many brain cells you lose each day because of decay and misuse, but you don't need to worry. You have enough to last for your whole lifetime!
• A human brain is larger than that of most other animals'. See how it compares.
• The right hemisphere controls the left side of the body, the left hemisphere controls the right side. These two hemispheres are connected by nerves through the corpus callosum.

Here are some more fun facts about the brain.

Your brain is the size of a large grapefruit, but it looks like a large pinkish-gray walnut. There are many folds and creases and it feels soft and squishy. It weighs about 1 pound at birth, 2 pounds at elementary age, and 3 pounds as an adult.

You can't understand what the brain does without knowing about the spinal cord. The spinal cord is an extension of the brain that runs down the middle of the back. The spinal cord is about 44 cm (19 inches) long in adults. It is protected by 33 bones called vertebrae. The brain and the spinal cord together are called the central nervous system. The central nervous system is one part of the nervous system. The rest, mostly nerves, is called the peripheral nervous system.

The wires of the nervous system are called neurons. The brain and the spinal cord contain billions of neurons. They send and receive information throughout your body.

All kinds of messages travel in neurons. If you touch a hot stove, neurons send a pain message from your finger to your brain. Your brain then sends a message, via neurons, through your spinal cord and nerves to the muscles in your arm to pull your hand away. Neurons can send signals to thousands of other neurons at a rate of up to 270 miles per hour.

The point of connection between two neurons is called a synapse — from the Greek word "synaptein" meaning to fasten together. Chemical and/or electric signals flow across this connection to communicate with the brain.

We don't really know how all parts of the brain work together. Scientists who study the brain, called neuroscientists, are doing experiments every day to try to solve these and other mysteries of the brain.

• Your brain contains approximately 100 billion neurons. Each neuron links to as many as 10,000 other neurons.
• If you could line up all the neurons in your body end to end, they would stretch almost 600 miles.
• More than 30,000 neurons can fit on the head of a pin.

You can take a look at some neurons at this online Gallery of Neurons.

Find out more at the Science Trek Nervous System site.

Some areas of the cerebral cortex are important for thinking and reasoning, some for voluntary movements and speech. There are also areas for your senses. You see, hear, smell, taste, and feel because of your brain. Your sense organs — fingers, ears, eyes, nose, and tongue — gather information about your surroundings and send this information through sensory neurons to special areas in the cerebral cortex. Visit Lobes of the Brain to take a closer look at where the different kinds of sensory signals go to in the cerebral cortex.

Some parts of the body such as your hands and lips have more sensory neurons than other parts. They are for detecting touch, pressure, roughness, smoothness, dry, wet, cold, hot, and pain. This body map, called a homunculus, shows you how much of the cerebral cortex is responsible for processing touch receptor information. And here's some additional information about your senses.

Our Science Trek Five Senses site has more information.

Although scientists used to believe that the brain could not repair itself, they are starting to discover ways in which brains can indeed do this. Despite this great news, brains don't heal as easily as a cut, scraped skin, or torn and broken bones. So it is very important for you to keep it healthy and to take care of it. Protecting your brain from accidents is very important. Take a look at this Brain Fitness guide for ways to keep your brain healthy.