The brain

What happened there? Yes, Selma made a nice catch. But inside Selma, what happened? Selma’s eyes see the ball. Messages go from the eyes to the brain.

Selma realises that a ball is approaching. Then the brain sends some other messages to the muscles of the legs. The muscles obey, and Selma's body moves towards the ball. Meanwhile the brain also sends messages to the muscles in her arms and hands so that they too can move toward the ball. And the brain calculates how the ball is going to move, so that Selma can be in the right position when the ball arrives.

That’s quite a lot at the same time, but the brain takes care of all of that within a second. The brain is very advanced. The brain is the most important organ in the human body. It works around the clock. Even when you’re asleep, the brain doesn’t switch off.

It’s the brain that makes sure you breathe while you sleep. And during the night, it’s working with everything you've learned during the day. You could almost say that it is studying. And when you wake up you know things a bit better than the day before. The brain needs oxygen and nutrition in order to function.

It gets these from the blood. The heart pumps a lot of blood to the brain all the time. There is a high blood flow. If the blood flow is too little, the brain doesn’t work. You lose vision and maybe balance, and you faint after just a few seconds.

If the brain is without blood for two or three minutes, its cells begin to die, and the brain can be seriously damaged. The brain is very delicate. But it is protected by the skull and three membranes - meninges. Together with a fluid - cerebrospinal fluid - these membranes function as shock absorbers between the skull and the brain. It’s as if you have a helmet inside the head.

The brain and the body cooperate. As you breathe, the brain sends messages to the lungs, and when you move, the brain sends messages to the muscles. The brain communicates with the various parts of the body. In order for it to work, the brain gets help from all the nerves in the body, the nervous system. The nervous system consists of two parts.

The brain and the spinal cord form the central nervous system. And the nerves in rest of the body the peripheral nervous system. Every second, millions of messages go to and from the brain, through the peripheral nervous system and the spinal cord. Messages about what you see, hear, feel, and many other things. This is why the nerve cells need to be connected to each other.

The connections are called synapses. Synapses are already starting to form before you’re born, and every time you experience something, new synapses are formed. During your first three years, one million new synapses are formed each second. The formation of synapses is very fast until puberty. The nerve cells keep forming new connections throughout life, but it happens quickest when you are young.

So, when Selma caught that ball, new synapses were formed in the brain, and next time Selma will be even better at catching balls. Nice work, Selma’s brain. And nice catch, Selma!