How does the human brain work?

The brain is the control and integration organ within the nerve system formed of a large number of gelatinous cells. Their number varies for each person and is somewhere between 100 thousand millions and 100 billions. Through the communication channels, these cells allow people to think and to remember.

Brain and the rest of the Human Body

While the brain only amounts for 2% of the total bodyweight, it uses more than 20% of all inspired oxygen. The main source of nutrition is glucose (a type of simple sugar). The brain burns one teaspoon of glucose (combined with oxygen and thyroid hormone) in an hour.

Neuron Structure and Function

The brain transfers and receives information through a network of neurons (nerve cells). Neurons are not visible with human eye and they consist of three parts: dendrites, a body of the cell and an axon. Dendrites are similar to tree branches, they receive information through small chemical drops (neurotransmitters). The body of the cell could be compared to an airport control tower. It receives signals and reacts much quicker than a lightning. From here the message travels into the axon (which looks like a little pencil) that releases an appropriate neurotransmitter. There are more than 50 of those. Best known are acetylcholine, serotonin and noradrenalin.

Neurotransmitters carry the messages that initiate anger, worries, attention, hunger, thirst, sexual desire, sleepiness or thanks to which we remember things. The cell receptors are very specialised so they receive only transmitters with certain chemical structures. As with any other body parts, the neurons also require proper nutrition so that they can they crease and send out sufficient amount of neurotransmitters. Insufficient suitable nutrition results in an imbalance and subsequent issues with memory and thinking.

Neurotransmitters could be called brain couriers. The chemicals jump over small spaces (synapses) between neurons. Each neuron has on its surface about 100,000 receptors (membranes) that function as offices receiving messages from various neurotransmitters. This process requires a specific relationship between the receptor and the neurotransmitters. It is like a key matching a certain lock. When the neurotransmitter connects to the neuron's receptor, it initiates a chain reaction in the cell. These reactions regulate and control all cell processes and the subsequent biological effect.

These basic mechanisms explain why thinking and memory function better with regular mental use, similarly to bodily functions improving with regular exercise. The idea of mental training is not new, but it is a very significant one. Training, education, adventure, sports and other experiences improve the brain's chemical and physiological properties.

Further Reading