The brain on the anatomical level is quite a complex organ: there are many sections within it and each section corresponds to a different set of functions within the body. The two pictures below illustrate the human brain at different angles, and also the difference between how the brain appears within the human body and on the surgical table (left) and how it appears after the brain has been extracted after death and preserved within formalin (right).
The brain is very vascular in vivo (in life) and uses glucose as its only source of energy. By vascular, I mean that the brain has many blood vessels surrounding the tissue. This is essential for two reasons: the huge amount of energy that the brain consumes requires a constant supply of glucose flowing within the blood at all times, and the blood vessels acts as an air-conditioner of sorts: the vast majority of your body heat is produced by your brain and without those vessels there to vent the heat away from the brain and towards your forehead and other areas in your body, your brain would fry!
It is rumoured that we humans use only 10% of our brains at any one time; however the truth surrounding this rumour is uncertain. Some of these functions are conscious whereas other ones are controlled by the ANS, which I’ll describe in detail in Peripheral Nerves: The Brain’s Scouts. The two major sections of the brain are the cerebrum and cerebellum, and I will be discussing this further in Cerebrum and Cerebellum.
The brain and spinal cord are both parts of the major component of the nervous system. As the graphic alongside shows, these two elements together create the central nervous system, or CNS for short, and they are interconnected with the peripheral nerves which communicate with muscles, organs and other cells within the body. These peripheral nerves altogether are referred to as the peripheral nervous system or PNS.
Nervous System: Functions
It is quite difficult to fully appreciate what the nervous system does unless there is a close analogy to compare it with. The closest analogy that I can think of is a power station.
A power station (whether it is via coal, solar or nuclear power) essentially has two main functions:
- It has people that closely monitor the signals being generated within the power station itself
- The people within the power station also track the signals being sent outward from the power station to the surrounding areas via electricity cables as well as signals that arrive through the alternate (AC) currents.
The first example relates to the engine room, which is comparable to the brain, and the second example relates to both the spinal cord and the peripheral nerves. The difference between a power station and the human brain is fairly obvious: instead of people that perform these tasks, the brain has hormones that it generates which serve to cater for the brain and for the rest of the body, and it also generates electrical pulses which radiate between cells to both generate conscious thought and to monitor autonomic functions (i.e. functions that we do not consciously pick up on) such as breathing and heartbeat.
In regards to the second function, the brain also does the same thing, but the structure is slightly different, albeit the principal is the same. Instead of electrical cables, as seen above, the brain sends signals out to the rest of the body via the spinal cord, which is essentially like a huge bundle of cables to the rest of the body, except on a much smaller level and then to the peripheral nerves, which are like individual cables to each building within the neighbouring area. Unlike a power station, though, the brain and body are much more intimately connected with each other, and are totally reliant on each other to make sure the human body functions optimally.