At any given time, about 20% of the oxygen and 20% of the blood running through our body is being used by our brain. At birth, our brain clocks in around one pound, and doubles in size over childhood. By adulthood, the male brain weighs about 3 pounds, while the female brain weighs about 2.7. Our brain serves various essential physical functions, like receiving messages via our five senses of touch, sight, smell, hearing and taste. Not only that, it also aids in molding our overall health, personalities, social exchanges, as well as simply keeps us alive.
Anatomically speaking, the brain is comprised of several distinct components and four separate lobes, each with their own functions. And neurons–aka nerve cells–are considered the brain and nervous system’s fundamental units. They receive sensory input from the world around us, transform and broadcast electrical signals within the body, and relay motor directions to our muscles. In fact, who we are is defined by the interactions among the approximately 100 billion neurons that float around in our bodies.
Neurons are made up of three major parts:
- An axon, which is a thin, long structure that transmits action potentials, or electrical messages.
- Dendrites, which are projections that receive electrical messages.
- A soma, aka the cellular body.
There are three major classes of neurons:
- Motor neurons are in control of voluntary muscular activity, like speaking; they also carry messages from neurons in the brain to our muscles.
- Sensory neurons shuttle information from our sensory organs (like the ears and eyes) to the brain.
- Interneurons is a term used to refer to all other neurons.
Scientists currently believe that neurons are the most diverse type of cell; there are hundreds of different subtypes within the above major denominations, each with a particular function related to the relaying of messages within our bodies.