The Pathway of a Nerve Impulse
Knowledge of the human nervous system and familarisation with the
key terms associated with it is an essential part of training in
many therapies - such as Massage, Aromatherapy, Accupuncture, Shiatsu,
and many others.
This page summarises basic information about the functioning of
nerves.
In a general case, the pathway of a nerve impluse may be
summarised as in the following diagram:
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Figure (1): The Pathway of a Nerve Impulse
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- This indicates that the first event in this sequence
is some "Stimulus". ("Stimuli" is the
plural form, referring to more than one stimulus.)
In this context, a stimulus is something that human sensory
receptors are able to detect.
Examples may include: Sounds; Physical contact; Tastes; Visual
stimuli, etc..
- The next stage in the pathway is the "Sensory Receptors" sensing
the stimulus.
These receptors are located all over the body but some types of receptors are
in specific areas of the body (e.g. taste receptors in the mouth).
- Sensory neuron(s) then transmit information from the
sensory receptor(s) to the Central Nervous System (i.e.
the brain and spinal cord, sometimes referred to in the
abbreviated form: C.N.S.). This is happens because peripheral
nerves all connect to the spinal cord via the network of
nerves within the nervous system.
- The information so received by the C.N.S. is further
transmitted by relay neurone(s) with the C.N.S.
This is shown in more detail in Figure (2), below.
The information may or may not be processed in the brain.
Some stimuli lead to "reflex responses" that
can be described in terms of the "Simple Reflex Arc",
whereas other stimuli (such as all visual stimuli) always
involve processing by the brain. More information about the "Simple Reflex Arc" is
included in Figure (2), below.
Following either "Simple Reflex Arc" response,
or processing by the brain, neural "instructions" may
be sent via a motor neurone to an effector (that is usually
a muscle or gland). In this way, the effector is instructed
to take action. This action may be physical movement of a
muscle (and so
possibly
also a limb), or some chemical action by a gland. Whatever
the consequent action, this has occurred due to the function
of the nervous system, in response to
the initial stimulus (or stimuli).
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A "Simple Reflex Arc"
The following diagram illustrates the sequence of events described
above in more detail, specifically for the case of the "simple
reflex arc". Theefore this diagram shows a vertebra of the
spine, but does not also include the brain.
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Figure (2): "Simple Reflex Arc"
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This is the end of this article but further information about Neurons
and about Diseases and Disorders
of the Nervous System are included on other pages of this website.
... End of Article ...
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