Neuron

Neuron is also known as Neurone or Nerve Cell. It is a cell which is electrically excitable and transmits information through electrical and chemical signals. The transmission of these signals between Neurons occurs through Synapses (Specialized connections with other cells). Through Neural Networks neurons are connected to each other. It is the key component of Nervous System which includes Brain, Spinal Cord and Central Nervous System.

ANATOMY

They are highly specialized for the cellular signals transmission and processing. Due to the diversity of their functions, they also have diversity in their shape, size and Electrochemical properties. The body of the Neuron is called Soma. It contains a Nucleus and it synthesizes Protein. The Dendrites of a neuron are its cellular extensions with many branches. The overall structure is referred as a Dendritic Tree. This is the region where inputs to the neurons occur through Dendritic Spine. Neurons also have Axons which are fine cable like projections that can extend tens of thousands of times the diameter of Soma in length. Axons carry Nerve Signals away from Soma. Normally a Neuron has only one Axon but this Axon extends its branches to communicate with target cells.

CLASSIFICATION

Anatomical characterization of most Neurons is as follows.

Unipolar
Bipolar
Multipolar
Golgi I
Golgi II

Some of the unique Neuronal types according to their location in Nervous System are as follows.

Basket Cells
Betz Cells
Lugaro Cells
Medium Spinary Neurons
Purkinje Cells
Renshaw Cells
Unipolar brush Cells
Granule Cells
Anterior Horn Cells
Spindle Cells

FUNCTIONAL CLASSIFICATION

According to their functioning Neurons are classified in three type i.e.

Afferent Neurons:

These Neurons transmit information from tissues and organs to Central Nervous System. They are also named as Sensory Neurons.

Efferent Neurons:

These Neurons convey signals from Central Nervous System to the cells. They are named as Motor Neurons.

Interneurons:

These Neurons serve as a connection between different neurons.

CLINICAL SIGNIFICANCE

There are many diseases related to the Neurological disorders which are as follows.

Charcot-Marie-Tooth Disease; is a Heterogeneous inherited disorder of nerves due to loss of muscle tissue and touch sensation in feet and legs.
Alzheimer ’s disease; it is a Neurodegenerative disease resulting in declining daily living and behavioral changes. The symptoms of it are Amnesia, Cognitive (Intellectual) impairment, and also effecting decision and plan making functions.
Parkinson’s Disease; degenerative disorder of Central Nervous System resulting in incapability of motor skills and speech
Myasthenia Gravis; it is a neuromuscular disease causing muscle weakness and fatigue during simple activities.