Elements of Neurology

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Elements of neurology Organs of the nervous system are basically formed of the

neurons. Other associated or supporting cells of the nervous system

are known as neuroglia or glial cells. These include microglia, schwann cells, oligodendrocytes and ependymal cells.

Neurons and glial cells have their intercellular substance known as neuropile more pronounced in the brain and spinal cord

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Elements of neurology…

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Neurons:

This is a nerve cell (basic unit of NS) and all of its processes. A neuron has two parts; cell body (soma) and processes. Cell body contains a nucleus and all necessary organelles for metabolic activity. Processes are for impulse conduction; an axon (long and only one per cell) conducts the impulses away from the cell body while the dendrites (short and one or more per cell) conduct towards.

Neuron cont…..

Neurons are classified according to the number of processes into: Pseudounipolar or unipolar Bipolar Multipolar

According to function as: Sensory Motor Association, intermmediate or internuncial

According to length of an axon into: Golgi type I – relatively short axons Golgi type II – relatively long axons

According to myelination of an axon into: Myelinated neuron Non-myelinated neuron

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Nervous system The nervous system is formed of the following organs:

i. Brainii. Spinal cordiii. Nervesiv. Ganglia (sing. Ganglion)

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Nervous system…

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Nervous system…

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The ANS has two divisions named as craniosacral (parasympathetic) outflow and thoracolumbar (sympathetic) outflow.

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Nervous system…

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Parasympathetic

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Dermatome The unilateral area of skin innervated by the fibers of a

single spinal nerve is called a dermatome; the unilateral muscle mass receiving innervation from the fibers conveyed by a single spinal nerve is a myotome

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Applied anatomy Referred pain

Referred pain, also called reflective pain, is pain perceived at a location other than the site of the painful stimulus. An example is the case of ischemia brought on by a myocardial infarction (heart attack), where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury.

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