Table of Contents
Of neurons and more
Our brain is more complex than we imagine. When talking about brain cells, the first ones that come to mind are the neurons, which are certainly the ones that are in charge of gathering the information collected by our senses, analyzing it and sending a response back, so that an action can be executed. But there are other cells present in our nervous system that not only support neurons, but also develop other important functions that keep our brain up and running.
The Central Nervous System (CNS)
The CNS comprises the brain and the spinal cord. An average adult human brain weights between 1.3 to 1.4 kg and is divided in two parts, or hemispheres: the left and the right hemispheres. This division is used mainly to simplify the study of the brain, because both hemispheres are connected through a group of nerve fibres located right in the middle, known as corpus callosum.
Electric cells: Neurons
Neurons are the building blocks of the CNS. It was thought that the number of neurons in the human brain was around 100 billion, but a recent study performed in 2009 in the Universidade Federal do Rio de Janeiro, scientists estimated that the number of neurons was close to 86 billion, which is a similar to the number of neurons present in the brain of other non-human primates, like chimps.
The top of the tree is composed by the cell body from which one or more ramifications project; these projections are known as dendrites. The trunk of the tree would then be the axon, a thicker and larger structure that comes out from the cell body and ends up in what is known as the axon terminal, and looks a lot like the roots of a tree.
Nerve terminals located in every corner of our body, including our internal organs, gather the information that our body collects through our senses.
It is known that an electric impulse travels at a speed of 0.1 to 100 m/s, which allows a very fast response to any stimulus.
Neurons gather all the information, process it and send a response back to where it is needed. For example, when you touch something very hot, the temperature stimulus activates receptors on your skin; these receptors send a message to the brain, which analyses the information and tells your hand muscles to move and get away from whatever is burning you.