Neurons are the messenger cells of the nervous system. There are more than 100,000 million neurons specialized in the transmission of information through electrical impulses, but, unlike other cells in the human body, they are more specialized and do not carry out cell division, but are generally generated by some types of stem cells.
In this article we will talk about the neuron: what it is, types, structure and functions .
What are neurons
Neurons are the messenger cells of the nervous system that process and transmit messages from one place in the nervous system to another, in the form of electrical signals called nerve impulses.
There are more than 100,000 million neurons specialized in the transmission of information through electrical impulses, but unlike other cells in the human body, they are more specialized and do not carry out cell division, but are usually generated by some types of stem cells.
What is the synapse
This is the name given to the union or connection between two neurons . They are small interneuronal spaces through which signals cross, using chemical substances that a neuron releases. The synaptic bouton is the structure that transmits signals to the other cell through the synapse.
The electrical impulse or signal must cross the gap (the synapse) to continue its way to or from the central nervous system. First, the impulse or signal is conducted along the axon of the sending neuron, that is, the one that sends the impulse. This triggers the release of neurotransmitters that cross the synaptic cleft or space between neurons, and a nerve impulse is then unleashed in the receiving neuron.
Neuron Characteristics:
Neurons are the fundamental building blocks of the nervous system, responsible for transmitting and processing information.
Following are some of the main characteristics of neurons:
- Stimulus: Neurons have the ability to respond to stimuli, such as light, sound, or chemical signals. When stimulated, they generate and transmit electrical impulses, known as action potentials, along the impulse.
- Conductivity: Neurons have long, branching extensions called dendrites and axons that enable them to transmit electrical signals over long distances. Dendrites receive incoming signals from other neurons, while axons transmit outgoing signals from neurons.
- Integration: Neurons integrate incoming signals from various sources, both excitatory and inhibitory. These signals are summarized in the neuron’s cell body, or soma, and if the combined signals are strong enough, they trigger an action potential.
- Synaptic Transmission: Neurons communicate with each other through synapses. At the synapse, the axon terminal of one neuron releases chemical messengers called neurotransmitters, which then bind to receptors on the dendrites or cell body of the receiving neuron. This transmission can be excitatory or inhibitory, influencing whether the receiving neuron will generate an action potential.
- Plasticity: Neurons have the ability to change their structure and function in response to experience or injury. This phenomenon is known as neural plasticity and plays an important role in learning, memory formation, and recovery from brain damage.
- Diversity: Neurons come in many shapes and sizes, each specialized for a particular function. For example, sensory neurons transmit information from sensory organs to the central nervous system, motor neurons control muscle movement, and interneurons facilitate communication between different neurons in the central nervous system.
Understanding the characteristics of neurons is essential to understanding how information is processed and transmitted in the nervous system. If you have further questions or need additional clarification, don’t hesitate to ask!
Structure of neurons
Like every cell, a neuron has a nucleus that contains genetic material (DNA) and functions as a cellular control center. Surrounding it is the cytoplasm, from which a long structure surrounded by a cell membrane is formed. In a neuron there are three very important parts that are essential to identify it:
Soma
It is the body of the cell (cell body) that contains its basic components, that is, its nucleus, ribosomes, mitochondria and the endoplasmic reticulum. From this part the axon and dendrites are formed, and it combines and integrates nerve signals and then sends them to other neurons or muscle/glandular cells through the axon. In addition, protein synthesis also takes place in the soma.
Dendrites
They are branches that begin in the soma and that receive signals from other neurons by connecting with them. These structures give a particular appearance to the neurons and become thinner with each branch. However, some neurons do not have dendrites.
Axon
It is a single long, thin branch through which nerve signals are transmitted. Sometimes, branches occur at the axon terminal. The axon is covered with a myelin sheath, a fatty layer that protects the cell, insulates the axon and facilitates nerve transmission.
Types of neurons
Next, we show you what the types of neurons are:
- Sensory : carry signals from receptors to the brain and spinal cord. The information they carry is based on sensory stimuli such as heat, light and chemicals.
- Motor : they carry instructions from the central nervous system to other parts such as muscles and glands, that is, to the effectors. The organs or structures that react when stimulated are called effectors.
- Relay : large neurons that carry messages from one part of the central nervous system to another.
On the other hand, association neurons or interneurons, which are normally located in the central nervous system, link sensory neurons with motor neurons.
Functions of neurons
What do neurons do? Among the various types of brain cells, neurons are the only ones capable of processing and transmitting messages from one place to another in the nervous system , in the form of electrical signals called nerve impulses.
For a nerve impulse to be generated, a neuron has to be stimulated. A sound, a light, or the pressure of a hand on your wrist, for example, can cause an impulse that releases neurotransmitters and stimulates another neuron.