The cerebrum, seen from above, showing the left and right hemispheresThe brain is the body’s control centre. It is in charge of how your heart beats and how your lungs suck in air. It controls your muscles. It also enables you to think, learn and feel sadness or joy. The spinal cord is a thick bunch of nerves running from the brain down the spine. Branching off from it is a complex network of hair-like nerves. These run to every part of the body. The brain sends and receives signals along these nerves. The brain works all the time, even when we are asleep.
Parts of the brain
A cross-section through the brainThe brain is made up of several parts. The brain stem links the brain with the spinal cord. It controls breathing and heart rates, eye movements and sleep. The hypothalamus controls body temperature, thirst and hunger, as well as much of the hormone system. The cerebellum controls the muscles, ensuring that body movements are smooth, not jerky. The cerebrum is by far the largest part. It is responsible for thought, intelligence, feeling, memory and movement. It has two halves, called hemispheres, left and right.
The brain and nerves are made of billions of nerve cells. These are called neurons. When you think, tiny electrical signals are being passed from neuron to neuron inside your brain. They whizz along at more than 400 km/h (250 mph).
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