LABEL THE PARTS OF A TYPICAL NEURON (1, 2, 3, 4, 5, 6) SHOWN

Medically reviewed by Nancy Hammond, M.D. — By Carly Vandergriendt and Rachael Zimlich, RN, BSN — Updated on February 28, 2022

Neurons, also known as nerve cells, send và receive signals from your brain. While neurons have a lot in common with other types of cells, they’re structurally và functionally unique.

Bạn đang xem: Label the parts of a typical neuron (1, 2, 3, 4, 5, 6) shown

Specialized projections called axons allow neurons lớn transmit electrical & chemical signals to lớn other cells. Neurons can also receive these signals via rootlike extensions known as dendrites.

A 2009 study estimated that the human brain houses about 86 billion neurons. The creation of new nerve cells is called neurogenesis. While this process isn’t well understood, we know that it’s much more active when you’re an embryo. However, 2013 evidence suggests that some neurogenesis occurs in adult brains throughout our lives.

As researchers gain insight into both neurons & neurogenesis, many are also working khổng lồ uncover link to neurodegenerative diseases such as Alzheimer’s và Parkinson’s.


Share on PinterestIllustration by Sophia Smith
Parts of a neuron
Neurons vary in size, shape, and structure depending on their role và location. However, nearly all neurons have three essential parts: a cell body, an axon, và dendrites.

Cell body

Also known as a soma, the cell body toàn thân is the bộ vi xử lý core section of the neuron. The cell toàn thân contains genetic information, maintains the neuron’s structure, & provides energy to lớn drive activities.

Like other cell bodies, a neuron’s soma contains a nucleus và specialized organelles. It’s enclosed by a membrane that both protects it and allows it khổng lồ interact with its immediate surroundings.

Axon

An axon is a long, tail-like structure. It joins the cell toàn thân at a specialized junction called the axon hillock. Many axons are insulated with a fatty substance called myelin. Myelin helps axons lớn conduct an electrical signal.

Neurons usually have one main axon.

Dendrites

Dendrites are fibrous roots that branch out from the cell body. Like antennae, dendrites receive và process signals from the axons of other neurons. Neurons can have more than one mix of dendrites, known as dendritic trees.

How many they have generally depends on their role. For instance, Purkinje cells are a special type of neuron found in a part of the brain called the cerebellum. These cells have highly developed dendritic trees which allow them to lớn receive thousands of signals.


Share on PinterestIllustration by Sophia Smith
Neurons vary in structure, function, & genetic makeup. Given the sheer number of neurons, there are thousands of different types, much like there are thousands of species of living organisms on Earth.

However, there are five major neuron forms. Each combines several elements of the basic neuron shape.

Multipolar neurons. These neurons have a single axon và symmetrical dendrites that extend from it. This is the most common form of neuron in the central nervous system.Unipolar neurons. Usually only found in invertebrate species, these neurons have a single axon.Bipolar neurons. Bipolar neurons have two extensions extending from the cell body. At the over of one side is the axon, and the dendrites are on the other side. These types of neurons are mostly found in the retina of the eye. But they can also be found in parts of the nervous system that help the nose and ear function.Pyramidal neurons. These neurons have one axon but several dendrites to khung a pyramid type shape. These are the largest neuron cells & are mostly found in the cortex. The cortex is the part of the brain responsible for conscious thoughts.Purkinje neurons. Purkinje neurons have multiple dendrites that fan out from the cell body. These neurons are inhibitory neurons, meaning they release neurotransmitters that keep other neurons from firing.

In terms of function, scientists classify neurons into three broad types: sensory, motor, and interneurons.

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Sensory neurons

Sensory neurons help you:

tastesmellhearseefeel things around you

Sensory neurons are triggered by physical and chemical inputs from your environment. Sound, touch, heat, & light are physical inputs. Smell and taste are chemical inputs.

For example, stepping on hot sand activates sensory neurons in the soles of your feet. Those neurons send a message lớn your brain, which makes you aware of the heat.

Motor neurons

Motor neurons play a role in movement, including voluntary and involuntary movements. These neurons allow the brain and spinal cord lớn communicate with muscles, organs, và glands all over the body.

There are two types of motor neurons: lower and upper. Lower motor neurons carry signals from the spinal cord to lớn the smooth muscles và skeletal muscles. Upper motor neurons carry signals between your brain và spinal cord.

When you eat, for instance, lower motor neurons in your spinal cord send signals lớn the smooth muscles in your esophagus, stomach, & intestines. These muscles contract, which allows food lớn move through your digestive tract.

Interneurons

Interneurons are neural intermediaries found in your brain & spinal cord. They’re the most common type of neuron. They pass signals from sensory neurons và other interneurons khổng lồ motor neurons and other interneurons. Often, they size complex circuits that help you to react khổng lồ external stimuli.

For instance, when you cảm ứng something sharp lượt thích a cactus, sensory neurons in your fingertips send a signal to lớn interneurons in your spinal cord. Some interneurons pass the signal on to motor neurons in your hand, which allows you khổng lồ move your hand away. Other interneurons send a signal to the pain center in your brain, & you experience pain.


Neurons send signals using action potentials. An kích hoạt potential is a shift in the neuron’s potential electric energy caused by the flow of charged particles in và out of the membrane of the neuron. When an action potential is generated, it’s carried along the axon lớn a presynaptic ending.

Action potentials can trigger both chemical & electrical synapses. Synapses are locations where neurons can pass these electrical and chemical messages between them. Synapses are made up of a presynaptic ending, a synaptic cleft, và a postsynaptic ending.

Chemical synapses

In a chemical synapse, the neuron releases of chemical messengers called neurotransmitters. These molecules cross the synaptic cleft & bind to receptors in the postsynaptic ending of a dendrite.

Neurotransmitters can trigger a response in the postsynaptic neuron, causing it to lớn generate an action potential of its own. Alternatively, they can prevent activity in the postsynaptic neuron. In that case, the postsynaptic neuron doesn’t generate an action potential.

Electrical synapses

Electrical synapses can only excite. These synapses form when two neurons are connected by a gap junction. This gap is much smaller than a chemical synapse và is made up of ion channels that help transmit a positive electrical signal.

Because of the way these signals travel, signals move much faster across electrical synapses than chemical synapses. However, these signals can diminish from one neuron lớn the next. This makes them less effective at transmitting repeated signals.


While research has advanced our understanding of neurons in the last century, there’s still much we don’t understand.

For instance, until recently, researchers believed that neuron creation occurred in adults in a region of the brain called the hippocampus. The hippocampus is involved in memory và learning.

But a 2018 study found that the production of neurons in the hippocampus actually drops after birth. This means that virtually no new neurons are created there by adulthood.

Experts considered this discovery a setback in terms of using neurogenesis lớn treat diseases like Alzheimer’s và Parkinson’s. These conditions are both the result of neuron damage và death.

There is still hope, though, that neural stem cells can be used khổng lồ make new neurons. Neural stem cells can produce new neurons, according to the National Institute of Neurological Disorders and Stroke. But researchers are still trying to lớn figure out the best way to use these stem cells lớn produce specific types of neurons in the laboratory setting.

If this can be done, these nerve cells could be created khổng lồ replace those that are lost through age, damage, and disease.

Ongoing clinical trials

Many clinical trials are currently underway to kiểm tra the use of newly created neural cells. For example, this one targets people who have had an ischemic stroke.

Also, a 2019 study used fluorescent probes lớn observe real-time activity in the nerve cells of mice. This công nghệ could be used khổng lồ help maps brain activity, uncover the problems that lead to lớn neurological disorders, and advance the field of artificial intelligence.


Nervous system cells are called neurons. They have three distinct parts, including a cell body, axon, and dendrites. These parts help them lớn send & receive chemical and electrical signals.

While there are billions of neurons & thousands of varieties of neurons, they can be classified into three basic groups based on function. These are motor neurons, sensory neurons, & interneurons.

There’s still a lot we don’t know about neurons và the role they play in the development of certain brain conditions. But many research projects and clinical trials are underway lớn try và find those answers.

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