The structure of human brain.

The brain is made up of two halves. Different areas of the brain have different functions. All nerve cells in the brain, about 100 billion of them, are connected to one another and transmit information. This network of the nerve cells is expanded through learning and training. Our brain controls our actions, regulates our sleep, and allows us to feel sensations like pain and joy. If it is damaged, maybe due to a stroke, one has to relearn a lot of things like speaking, walking, or eating.

How do nerve cells transmit signals?

Signals transmission through nerve cells is quite complicated. Like all the other cells, nerve cells also have a cell body with a nucleus. There are fine extended branches known as dendrites and a long 'tail' called the axon on the body of the nerve cells. Axons in the brain are smaller than 1 mm, whereas in the spinal cord they can be as long as 1 m. A chemical substance is released through an electrical impulse into the synapses present at the end of the axon. This chemical substance, known as the neurotransmitter, is transferred to the dendrite of another nerve cell and the signals are transmitted.

Why do we feel pain?

Pain is a warning signal telling us that there is some danger threatening our health. We feel pain through specific receptors, the sensors, in the skin. These can also be found in the organs and be found in the organs and the periosteum. Our body has two pain systems, a fast one and a slow one. If our hand touches a hot object, we withdraw it instinctively without even thinking. This is the fast pain system in action. However, the pain that comes later due to the burning skin or a blister, is transmitted by the slow pain system to the brain.

What is memory and why must we sleep?

It is the store of things learned and retained from our activity or experience. Our memory is a collection of knowledge, experiences, impressions, skills, habits, and many other things. It previous experiences as well as to build relationships. It has a lifelong storage capacity, and no computer of the world can match its performance. Short-term memory is the information that we are currently thinking of and it lasts for only a few seconds. Important things which we have experience and would not like to forget are transferred from short-term memory into long-term memory.

We may not know exactly why we need to sleep, but we do know that our body needs sleep to rest and recover. One becomes irritable and cannot concentrate. After several days of inadequate sleep, one may start hallucinating. The duration of sleep needed depends on the person and the age. While most babies sleep for more than 12 hours a day, some old people need only 5-6 hours of sleep.

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