The brain is the cognitive center of the higher animals, and humans. The brain is compared to a computer central processing unit (CPU). The brain has a complex substructure. These include macroscopic, microscopic, and submicroscopic features. Of special significance are neurons. These are typically illustrated in Figure 1.
What are it’s component parts? Notably axons, dendrites, synapses, and receptors.
Components of Neurons
A neuron is a nerve cell. It receives signals via chemicals called neurotransmitters. It then transmits the signals, electrically. A neuron consists of a cell body or soma, dendrites, and a single axon. It is one of many units that makes up the brain.
An axon is a fiber rather like a cable. It carries electrochemical signals from the soma to other neurons. The axon is surrounded by a series of short, cylindrical myelin sheaths along its length. These lie much like beads on a string. If the sheaths are damaged, the axon cannot transmit signals properly. This can lead to multiple sclerosis.
Dendrites are finger like receptors of signals coming from other neurons. Although the dendrites do not touch other neurons, they come close, leaving tiny gaps (synapses) to separate them. An important function of the dendrite is the integration of various input signals.
Synapses are the gaps between the axons of transmitting neurons and the dendrites of receptor neurons. Electrochemical signals are carried across the gap by neurotransmitter molecules. These end up at the receptor proteins located in the ends of dendrites.
There are various neurotransmitter chemicals. Each serves a different type of neuron. Among them are serotonin, acetylcholine, and dopamine. Serotonin imparts a feeling of well being. It is associated with the central nervous system, blood platelets, and the gastrointestinal tract.
Acetylcholine relates to the heart and skeletal musculature.
Dopamine may occur in increased levels in persons of extroverted personalities.
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