To understand how a nerve impulse travels along the neuron, the complete pathway of the neuron must be understood. The impulse is essentially a message that is sent to the brain.
What Is a Nerve Cell?
Just like other systems in the body, the smallest part of the nervous system must be examined first, which is the nerve cell. When a large number of these cells are bundled together, they create what is known as a nerve. Each nerve has many extensions of individual nerve cells. These long, thread-like pieces are where nerve impulses are transmitted. A type of nerve cell that has a specific function to deliver messages to the brain is called a neuron. These messages are nerve impulses, and each message is a quick, electrical impulse.
To understand how a nerve impulse travels, the structure of a neuron must be looked at first. Like many other cells, a neuron has a cell body, including a nucleus. But a neuron also includes many dendrites as well as an axon. Dendrites are the receptors on a neuron that receive messages from other cells, and an axon sends the message along to the other cells. The axon is a very important part of message transmission. Other parts of a neuron include a myelin sheath, which is the insulation for the axon, and the node of Ranvier, which is a small gap that facilitates faster transmission of messages.
Different Neuron Types
To further understand transmission and signals, it's a good idea to recognize the different types of neurons in the brain. The two main classifications of neurons are sensory and motor neurons, and they have two separate functions. Sensory neurons carry messages into the central nervous system from organs, while motor neurons carry messages in the opposite direction дуЅн_нс from the brain to the organs. Both types work together to facilitate message transmission 24 hours a day.
How the Impulse Travels
A synapse is a small gap between two neurons that are trying to send a message to one another. An axon of one neuron will send a message to the dendrite of another neuron, almost like fitting together pieces in a jigsaw puzzle. However, a small space appears there, and this is the synapse. The nerve impulse will travel down the length of the neuron to the end of the axon. When it reaches the axon, it releases chemicals into the brain called neurotransmitters. Familiar neurotransmitters include GABA, serotonin and dopamine. These chemicals are made to travel past the axon, through the synapse (gap), and then they deliver the message to the dendrite, which is essentially the receptor on the receiving neuron.
The Importance of Neurotransmitters
When a person has too low or too high of a type of neurotransmitter in his or her brain, it can cause mental health problems. For example, if a person has a low amount of the neurotransmitter serotonin, he or she may have clinical depression. In this case, an antidepressant, such as an SSRI (Selective Serotonin Reuptake Inhibitor) is prescribed so that the person's neurotransmitter level can get back to normal. When levels are "off," then the brain receives skewed messages.