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26 de abr. de 2021 · Last Updated: April 26, 2021. Nerve cells (AKA neurons) are the basic functional units of the nervous system, and the adult human brain is thought to contain around 86 billion of them. The role of a nerve cell is to receive information from cells and transmit this information to other cells.
- Kate Latham
- Overview
- How do you know where you are right now?
- The human nervous system
- Classes of neurons
- Sensory neurons
- Motor neurons
- Interneurons
- The basic functions of a neuron
- Anatomy of a neuron
- Dendrites
Introduction to neurons and glia. How the structure of a neuron allows it to receive and transmit information.
•The central nervous system (CNS) consists of the brain and the spinal cord. It is in the CNS that all of the analysis of information takes place.
•The peripheral nervous system (PNS), which consists of the neurons and parts of neurons found outside of the CNS, includes sensory neurons and motor neurons. Sensory neurons bring signals into the CNS, and motor neurons carry signals out of the CNS.
The cell bodies of some PNS neurons, such as the motor neurons that control skeletal muscle (the type of muscle found in your arm or leg), are located in the CNS. These motor neurons have long extensions (axons) that run from the CNS all the way to the muscles they connect with (innervate). The cell bodies of other PNS neurons, such as the sensory neurons that provide information about touch, position, pain, and temperature, are located outside of the CNS, where they are found in clusters known as ganglia.
Your ability to perceive your surroundings – to see, hear, and smell what’s around you – depends on your nervous system. So does your ability to recognize where you are and to remember if you’ve been there before. In fact, your very capacity to wonder how you know where you are depends on your nervous system!
If your perceptions indicate danger (“Oh no, the house is on fire!”), your ability to act on that information also depends on your nervous system. In addition to letting you consciously process the threat, your nervous system triggers involuntary responses, like an increase in heart rate and blood flow to your muscles, intended to help you cope with danger.
All of these processes depend on the interconnected cells that make up your nervous system. Like the heart, lungs, and stomach, the nervous system is made up of specialized cells. These include nerve cells (or neurons) and glial cells (or glia). Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances. Glia are also essential to nervous system function, but they work mostly by supporting the neurons.
In this article, we'll take a closer look at neurons, glia, and nervous systems. We'll see how the structure of neurons supports their function, and how they can be organized into circuits that process information and generate a response.
In humans and other vertebrates, the nervous system can be broadly divided into two sections: the central nervous system and the peripheral nervous system.
•The central nervous system (CNS) consists of the brain and the spinal cord. It is in the CNS that all of the analysis of information takes place.
•The peripheral nervous system (PNS), which consists of the neurons and parts of neurons found outside of the CNS, includes sensory neurons and motor neurons. Sensory neurons bring signals into the CNS, and motor neurons carry signals out of the CNS.
The cell bodies of some PNS neurons, such as the motor neurons that control skeletal muscle (the type of muscle found in your arm or leg), are located in the CNS. These motor neurons have long extensions (axons) that run from the CNS all the way to the muscles they connect with (innervate). The cell bodies of other PNS neurons, such as the sensory neurons that provide information about touch, position, pain, and temperature, are located outside of the CNS, where they are found in clusters known as ganglia.
Based on their roles, the neurons found in the human nervous system can be divided into three classes: sensory neurons, motor neurons, and interneurons.
Sensory neurons get information about what's going on inside and outside of the body and bring that information into the CNS so it can be processed. For instance, if you picked up a hot coal, sensory neurons with endings in your fingertips would convey the information to your CNS that it was really hot.
Motor neurons get information from other neurons and convey commands to your muscles, organs and glands. For instance, if you picked up a hot coal, it motor neurons innervating the muscles in your fingers would cause your hand to let go.
Interneurons, which are found only in the CNS, connect one neuron to another. They receive information from other neurons (either sensory neurons or interneurons) and transmit information to other neurons (either motor neurons or interneurons).
For instance, if you picked up a hot coal, the signal from the sensory neurons in your fingertips would travel to interneurons in your spinal cord. Some of these interneurons would signal to the motor neurons controlling your finger muscles (causing you to let go), while others would transmit the signal up the spinal cord to neurons in the brain, where it would be perceived as pain.
If you think about the roles of the three classes of neurons, you can make the generalization that all neurons have three basic functions. These are to:
1.Receive signals (or information).
2.Integrate incoming signals (to determine whether or not the information should be passed along).
3.Communicate signals to target cells (other neurons or muscles or glands).
Neurons, like other cells, have a cell body (called the soma). The nucleus of the neuron is found in the soma. Neurons need to produce a lot of proteins, and most neuronal proteins are synthesized in the soma as well.
Various processes (appendages or protrusions) extend from the cell body. These include many short, branching processes, known as dendrites, and a separate process that is typically longer than the dendrites, known as the axon.
The first two neuronal functions, receiving and processing incoming information, generally take place in the dendrites and cell body. Incoming signals can be either excitatory – which means they tend to make the neuron fire (generate an electrical impulse) – or inhibitory – which means that they tend to keep the neuron from firing.
Most neurons receive many input signals throughout their dendritic trees. A single neuron may have more than one set of dendrites, and may receive many thousands of input signals. Whether or not a neuron is excited into firing an impulse depends on the sum of all of the excitatory and inhibitory signals it receives. If the neuron does end up firing, the nerve impulse, or action potential, is conducted down the axon.
21 de sept. de 2023 · Nerve cells are also called. neurons. They are adapted to carry electrical impulses from one place to another. They feature: an. axon. – a single nerve fibre that carries nerve impulses away...
20 de jul. de 2018 · Neurons, also known as nerve cells, send and receive signals from your brain. While neurons have a lot in common with other types of cells, they’re structurally and functionally unique.
22 de mar. de 2022 · Overview. What are nerves? Nerves are like cables that carry electrical impulses between your brain and the rest of your body. These impulses help you feel sensations and move your muscles. They also maintain certain autonomic functions like breathing, sweating or digesting food. Nerve cells are also called neurons.
30 de oct. de 2023 · Nerves are the functional and structural units of the peripheral nervous system (PNS). They are composed of groups of individual specialized cells called neurons (or nerve cells), which transmit motor and sensory information back and forth between the PNS and central nervous system (CNS).
- Content Manager
- 3 min
Nerve Cells. Despite the specific molecular, morphological, and functional features of any particular nerve cell type, the basic structure of neurons resembles that of other cells. Thus, each nerve cell has a cell body containing a nucleus, endoplasmic reticulum, ribosomes, Golgi apparatus, mitochondria, and other organelles that are essential ...
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