How The Human Brain Works
The human brain controls how we interpret and integrate everything that is going on around and inside of us. The brain is divided into various sections with their own functions.
Neurons
When someone thinks of "brain cells," they normally mean neurons. These make up the main processing cells of the brain, passing on signals and integrating information. They are several specialized types of neuron according to where they are in the brain. Some have short connections, to relay and act on messages within their own region; others have long connections that go between different brain areas, the spinal cord and muscles.
Neurons work by first sending a signal along a long process, the axon; the signal is relayed to neighboring neurons through the release of neurochemicals at the end of the axon. These chemicals attach to receptors on a neighboring neuron, located on smaller processes called dendrites. The receptors relay the message to this neuron to act on whatever signal was given.
There are several types of neurochemicals that differ in function and location of both release and effect. These include serotonin, dopamine, norepinephrine and glutamate. Alterations in the normal levels of neurotransmitters can cause problems in both physical and emotional functioning.
Regions of the Human Brain
The brain can be divided in many ways including general function. The brainstem, which leads to the spinal cord, controls our reflexes, heart rate, digestive functions, breathing and blood pressure. The cerebellum, at the lower back of the brain, helps control and direct movement using information from the muscles, ears and eyes.
Deep within the brain, the limbic system contains the hippocampus, involved in memory storage and recall; the hypothalamus, involved in control of sleep, body temperature, appetite, and emotional response; the thalamus, which relays messages between the cerebral cortex and spinal cord, and the amygdala, involved in emotional response and hormone regulation.
The cerebral cortex, or cerebrum, is the large folded outside part of the brain. It's composed of four lobes, which appear twice as the brain is split into two hemispheres connected by a structure called the corpus callosum. In general each hemisphere responds to and controls the opposite side of the body to its position in the brain. Although the lobes have separate functions, there are many connections between them.
The occipital, parietal and temporal lobes integrate our senses with our memories to provide reactions to outside stimuli. The temporal lobe receives sound, smell and taste information, and has some memory functions; the parietal lobe receives touch, temperature, and taste information, and is also involved in language; the occipital lobe receives visual information. The frontal lobe is responsible for higher functions including concentration, attention, planning, problem solving and short-term memory; it also has a role in motor skills including speech.
Although the brain is composed of separate parts, they work together to control all our functions and reactions; damage to one part may not only affect the function there but to other areas as well.
References
- Mayo Clinic: How Your Brain Works
- Neuroscience For Kids
- The Human Brain Coloring Book; Marion Diamond, Arnold Scheibel, and Lawrence Elson; 1985
