Neurons

Neuron Definition

Neurons are specialized cells, fundamental to the nervous system, transmitting information to various body parts.

What is a Neuron?

Neurons, the fundamental units of the nervous system, play a crucial role in receiving and transmitting signals throughout the body. This communication occurs through both physical and electrical means, facilitated by various types of neurons.

The sensory neurons relay information from sensory receptor cells all over the body to the brain. In contrast, motor neurons convey information from the brain to the muscles. Interneurons, on the other hand, facilitate communication between various neurons in the body.

Neuron Structure

The shape and size of a neuron vary based on its function and location, consisting of three parts: dendrites, cell body, and axon.

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Parts of a neuron

Below are the different parts of a neuron:

Dendrites

These are tree-like structures that receive messages from other neurons and enable the transmission of messages to the cell body.

Cell Body

Each neuron comprises a cell body containing a nucleus, Golgi body, endoplasmic reticulum, mitochondria, and other essential components.

Synapse

It is the chemical connection where the terminal of one neuron meets the dendrites of another neuron.

Axon

The axon is a tubular structure that conducts electrical impulses from the cell body to the axon terminals, which then transmit the impulse to another neuron.

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Types of neurons

There are three different types of neurons:

Sensory Neurons

Sensory neurons transform external stimuli into internal signals, activating in response to sensory inputs. They transmit sensory information to the brain and spinal cord, featuring a pseudounipolar structure.

Motor Neurons

Found in the central nervous system, motor neurons are multipolar and extend their axons beyond the central nervous system. They transmit information from the brain to the body's muscles, representing the most common neuron type.

Interneurons

With a multipolar structure, interneurons connect solely to nearby sensory and motor neurons. They facilitate signal transmission between two neurons.

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Neuron Function

The functions of a neuron are:

Chemical Synapse

Chemical synapses function through a synaptic gap between neurons, where the action potential triggers the release of neurotransmitters from the presynaptic neuron's axon terminal. These neurotransmitters bind to receptors on the postsynaptic neuron, leading to the generation of a new action potential.

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Electrical Synapse

An electrical synapse occurs when two neurons are connected by gap junctions, allowing ions to pass directly from one neuron to another. This direct transmission of electrical signals is faster than chemical synapses due to the absence of neurotransmitter release and receptor binding.

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Frequently Asked Questions on Neurons

Ans. Neurons, also known as nerve cells or neurones, serve as the basic units of the brain and nervous system. They play crucial roles in receiving sensory input, transmitting motor commands, and processing and relaying electrical signals throughout the body.

Ans. The three types of neurons are - motor neurons, sensory neurons, and interneurons.

Ans. Neurons, comprising structures common to all eukaryotic cells like the cell body (soma), nucleus, endoplasmic reticulum (smooth and rough), Golgi apparatus, mitochondria, and other cellular components, are specialized cells.

Ans. The ability to become polarized or depolarized is necessary for all the transmission of nerve impulses.

Ans. Human neurons have more genomic DNA than non-neuronal cells.

Ans. Santiago Ramón y Cajal.