What is a Neuron? Parts and Function

Summary

This educational video delves into the anatomy of a neuron, the fundamental unit of the nervous system. It explains the roles of dendrites in receiving chemical messages via neurotransmitters, the soma's function in integrating these signals, and the axon's role in conducting electrical impulses. The video also highlights the significance of the myelin sheath in speeding up neural signals and the nodes of Ranvier that facilitate rapid signal transmission. Different neuron types, such as motor, sensory, and interneurons, are briefly introduced, each serving distinct functions within the nervous system.

Takeaways

• 🧠 A neuron is a nerve cell that forms the nervous system and facilitates the transmission of information throughout the body.
• 🌐 Dendrites are branched structures that receive messages from other neurons through neurotransmitters.
• 🔄 Neurons communicate using chemical messages called neurotransmitters, such as dopamine, acetylcholine, and endorphins.
• 🏢 The soma, or cell body, contains the nucleus and genetic material of the neuron and is responsible for sustaining its life.
• 🚀 The axon hillock is a critical structure that, if the signal is strong enough, generates an electrical charge known as an action potential.
• ⚡ The axon carries the action potential to the end of the neuron, and its length can vary from a few millimeters to several feet.
• 🛡️ The myelin sheath is an insulator that covers the axon, increasing the speed of the electrical signal and is formed by glial cells or Schwann cells.
• 🤺 Multiple sclerosis is a disease that disrupts the myelin sheath, hindering the communication of information within the body.
• 🔑 Nodes of Ranvier are gaps in the myelin sheath that allow the action potential to jump from node to node, increasing the speed of signal transmission.
• 🔗 Axon terminals or synaptic buds are where neurotransmitters are stored and released into the synapse to bind with the receptors of the next neuron.
• 🌈 Neurons can vary in appearance and function, including motor neurons, sensory neurons, and interneurons, each with distinct roles in the nervous system.

Q & A

What is a neuron and why is it important?

A neuron is an individual nerve cell that constitutes the nervous system, enabling the transmission of information throughout the human body. It is crucial for various functions including muscle movement, sensory detection, decision-making, and comprehension of speech.

What are dendrites and what is their function in a neuron?

Dendrites are small branches of a neuron that receive messages from other neurons in the form of chemical signals called neurotransmitters.

How do neurons communicate with each other?

Neurons communicate through chemical messages known as neurotransmitters, which are released by one neuron and bind to receptors on the dendrites of another neuron.

What is the role of the soma in a neuron?

The soma, or cell body, of a neuron contains the nucleus and genetic material. It is responsible for sustaining the life of the neuron and integrating and interpreting the signals received by the dendrites.

What is the axon hillock and why is it significant?

The axon hillock is a small structure that connects the soma to the axon. It is significant because it generates an electrical charge called an action potential if the signal is strong enough.

Describe the function of the axon in a neuron.

The axon is a long tube-like structure that carries the electrical signal, or action potential, from the neuron to the end of the neuron or to other cells.

What is the myelin sheath and how does it affect the speed of nerve signals?

The myelin sheath is a protective layer that covers the axon and acts as an insulator. It helps speed up the nerve impulse by allowing the electrical signal to 'jump' from one node of Ranvier to the next, rather than traveling continuously along the axon.

What is the difference between myelinated and unmyelinated axons?

Myelinated axons are covered by a myelin sheath, which speeds up the transmission of nerve signals. Unmyelinated axons lack this sheath and are generally slower in transmitting signals.

What are the nodes of Ranvier and how do they contribute to the speed of nerve impulses?

The nodes of Ranvier are small gaps in the myelin sheath where the electrical signal can 'jump' from one node to the next, a process known as saltatory conduction, which increases the speed of nerve impulses.

What is the function of the axon terminal?

The axon terminal, also known as synaptic buds, is the end of the axon where neurotransmitters are stored in synaptic vesicles. When the action potential reaches the axon terminal, these neurotransmitters are released to bind to receptors on the next postsynaptic neuron.

What is the synapse and how does it relate to the communication between neurons?

The synapse is a small gap or junction between two neurons where the neurotransmitters are released from the axon terminal of one neuron and bind to receptors on another neuron, facilitating communication between them without direct contact.

What are the different types of neurons and their functions?

There are several types of neurons including motor neurons that control muscle movement, sensory neurons that detect information from the environment, and interneurons that link motor and sensory neurons. Each type has a specific role in the nervous system.

Outlines

00:00

🧠 Understanding Neurons and Their Functions

This paragraph introduces the concept of neurons, emphasizing their role as the fundamental units of the nervous system. Neurons are responsible for transmitting information throughout the body, enabling a wide range of functions from muscle movement to sensory perception. The video script explains that neurons communicate via chemical messengers known as neurotransmitters, which bind to dendrites, the branch-like structures of neurons. The dendrites receive messages from other neurons, and these messages are then integrated and interpreted by the soma, or cell body, which contains the neuron's nucleus and genetic material. The soma's role is crucial for sustaining the neuron's life. The paragraph also introduces the axon hillock, a structure that initiates an electrical charge called an action potential if the incoming signal is strong enough. This action potential travels down the axon, a long tube-like structure that can vary greatly in length, from a few millimeters to several feet.

05:01

🔋 The Structure and Speed of Neuronal Transmission

The second paragraph delves into the mechanics of how neurons ensure fast transmission of signals. It discusses the myelin sheath, an insulating layer that covers the axon and is produced by glial cells or Schwann cells. The myelin sheath acts like an insulator, speeding up the electrical signal's travel along the axon. The paragraph also explains the difference between myelinated and unmyelinated axons, noting that most neurons in the central and peripheral nervous system are myelinated for quick communication. The color of the myelin sheath is highlighted, with myelinated axons appearing white, which is the basis for the term 'white matter' in the brain. The paragraph further explains the nodes of Ranvier, gaps in the myelin sheath that allow for a faster transmission of action potentials along the axon through a process known as saltatory conduction. Finally, the paragraph describes the axon terminals or synaptic buds, where neurotransmitters are stored in synaptic vesicles and are released into the synapse, the junction between two neurons, to communicate with the next neuron in the chain.

Keywords

💡Neuron

A neuron is an individual nerve cell that constitutes the fundamental unit of the nervous system. It plays a critical role in transmitting information throughout the body, enabling various functions such as muscle movement, sensory perception, and cognitive processes. In the video, the neuron is described as essential for actions like moving muscles, detecting temperature, and understanding speech.

💡Dendrites

Dendrites are the branching extensions of a neuron that receive signals from other neurons. They are likened to 'little fingers' in the script, emphasizing their role in receiving messages in the form of neurotransmitters. These chemical messengers are crucial for neuronal communication, and dendrites are the primary sites where this reception occurs.

💡Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals across a synapse from one neuron to another. The video mentions various types of neurotransmitters, such as dopamine, acetylcholine, and endorphins, each with distinct functions like pleasure seeking, muscle control, and pain relief, respectively. They bind to receptors on dendrites, initiating the process of signal transmission.

💡Soma

The soma, or cell body of a neuron, contains the nucleus and is responsible for maintaining the neuron's health and sustaining its life. It is depicted as the central hub where the dendrites' received signals are integrated and interpreted. The soma's role is crucial for the neuron's overall function and survival.

💡Axon

The axon is a long, tube-like projection of a neuron that carries electrical signals called action potentials from the soma to other neurons or target cells. The video explains that axons can vary greatly in length, from a few millimeters to several feet, and are essential for the rapid transmission of information within the nervous system.

💡Axon Hillock

The axon hillock is a small region where the soma connects to the axon. It is significant because if the signal received by the dendrites is strong enough, it generates an action potential here. This potential then travels down the axon, indicating the axon hillock's role as a threshold detector for neuronal firing.

💡Myelin Sheath

The myelin sheath is a protective layer that covers many axons, increasing the speed of electrical signal transmission. It is likened to rubber tubing around a wire, providing insulation and speeding up the impulse. The video also touches on the importance of myelin in diseases like multiple sclerosis, where its disruption can impede communication within the body.

💡Nodes of Ranvier

Nodes of Ranvier are the small gaps in the myelin sheath where the axon is exposed. They play a critical role in speeding up the conduction of electrical signals along the axon by allowing the action potential to 'jump' from one node to the next. This process, known as saltatory conduction, is highlighted in the video as a mechanism for rapid signal transmission.

💡Synapse

The synapse is the junction between two neurons where communication occurs. It is a small gap across which neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron. The video explains that this gap ensures that neurons do not physically touch, allowing for a controlled and specific exchange of signals.

💡Axon Terminal

Axon terminals, also known as synaptic boutons, are the end branches of an axon where neurotransmitters are stored in synaptic vesicles. When an action potential reaches the axon terminal, these vesicles release neurotransmitters into the synapse, continuing the signal transmission to the next neuron. The video describes this as the endpoint of the neuron's signal pathway.

💡Motor Neuron

A motor neuron is a type of neuron that carries signals from the central nervous system to the muscles, allowing for movement. The video mentions that motor neurons are often depicted as the typical neuron structure, with multiple branching dendrites and a long axon, emphasizing their role in the efferent pathway of the nervous system.

💡Sensory Neuron

Sensory neurons are responsible for transmitting information from sensory receptors to the central nervous system. They are described in the video as detecting stimuli such as heat, cold, and other environmental factors. Sensory neurons are crucial for the afferent pathway, bringing external information into the nervous system for processing.

💡Interneuron

Internurons are neurons that connect other neurons, often found within the central nervous system. They are described as bipolar neurons in the video, linking motor and sensory neurons to facilitate communication between different parts of the nervous system. Interneurons play a vital role in processing and integrating information within neural networks.

Highlights

Neurons are individual nerve cells that make up the nervous system and allow information to travel throughout the human body.

Dendrites are the branch-like structures that receive messages from other neurons through neurotransmitters.

Neurotransmitters are chemical messengers like dopamine, acetylcholine, and endorphins that transmit signals between neurons.

The soma, or cell body, contains the nucleus and genetic material of the neuron, sustaining its life.

The axon hillock generates an electrical charge called an action potential if the signal is strong enough.

The axon is a long tube that carries the electrical signal from the soma to the end of the neuron.

The myelin sheath is an insulator that covers the axon, speeding up the transmission of electrical signals.

Multiple sclerosis is a disease that disrupts the myelin sheath, affecting communication through the body.

Axons can be myelinated, which are covered by myelin, or unmyelinated, which lack a myelin sheath.

White matter in the brain is made up of myelinated axons, giving it its characteristic white color.

Nodes of Ranvier are gaps in the myelin sheath that allow action potentials to jump from node to node, increasing speed.

Axon terminals, or synaptic buds, are where neurotransmitters are stored and released to bind to receptors of the next neuron.

The synapse is the small gap between two neurons where neurotransmitters are released and bind to receptors.

Neurons can vary in appearance, with motor neurons, sensory neurons, and interneurons having distinct structures and functions.

Motor neurons are typically bipolar and help move muscles, while sensory neurons detect information from the environment.

Interneurons are found in the retina and help link motor and sensory neurons.

Transcripts

[Music]

all right guys in this video we're going

to talk about the parts of a neuron and

for some background information remember

a neuron is an individual nerve cell

that makes up the nervous system it

allows information to travel throughout

the human body so whether you want to

move your muscles detect things in the

world that are hot or cold speak make

decisions or even understand what i'm

saying all of that cannot be done

without a healthy functioning neuron so

let's go over how it works the first

structure i want to focus on are these

little branches right here it's almost

like the little fingers on my hand these

are called

dendrites what are they called

dendrites so all of these

little branches

are dendrites and what do dendrites do

dendrites receive the message from

another neuron

the way we communicate is through

language and words right but neurons

communicate through chemical messages

specifically things called

neurotransmitters

imagine for example this is a

neurotransmitter there's many types it

could be dopamine which is a reward

seeking right pleasure neurotransmitter

it could be acetylcholine which controls

our muscles it could be endorphins which

is a pain reliever this is going to be

released by another neuron and it's

going to bind

on the dendrites it's going to be

received like a lock and key this

dendrite this dendrite this your android

whichever it is it's going to bind to

that

receptor site

now once it binds it's going to be

integrated and interpreted by this area

right here called the

soma

or cell body and the soma is where you

can find the nucleus right the genetic

material of the neuron it helps sustain

life of the neuron as well

now before information travels down this

long tube right here notice that the

soma connects to this tube by this

little structure right here okay

this is what we call

the axon

hillock okay axon hillock and this is

important why is it important

if the signal is strong enough okay

we'll talk about that in another video

if the if the information is strong

enough what's going to happen is this is

going to generate an electrical charge

called an action potential and here is

our electrical charge

there we go right here okay and that's

going to start in the axon hillock

and that's going to travel down this

long tube right here what is that tube

called

this is called and is in here the axon

and the cool thing about the axon is

that it could be very very tiny just a

few millimeters in the brain to up to a

few feet long let's say going from your

spinal cord to your toes so the axon

carries the electrical signal the active

potential down here

to the end of the neuron

now this is important

you want things to go fast right if

you're an emergency something in danger

you want that charge to go really fast

on the axon well how do we ensure that

it's a fast signal

the axon is covered by something called

the mylon or mylon sheath okay the mylon

sheath

you might have heard the words

glial cells or schwann cells a lot of

this means essentially the same thing

you have glial cells or more

specifically schwann cells that form or

make this mylon and the mylon acts as an

insulator right it's like kind of like a

a wire to a wire with rubber tubing

around it helps protect and speed up

that impulse so it goes really fast and

just for some background information if

you've ever heard of something called

multiple sclerosis right this horrible

disease that affects communication

through the body it disrupts the myeloma

it destroys the myeloma so information

doesn't get from point a to point b

now not every axon has nylon right in

fact we can kind of divide this into two

types we can say there are you know

unmyelinated

unmyelinated

axon and then there's also

myelinated axon

okay myelinated

most of there we go there's a d

myelinated ammonite most of the neurons

in the nervous system central peripheral

are

myelinated why because we need things to

happen very quickly but of course there

are axons that are unmyelinated now the

color of it and this is actually

interesting to know

is the color is white okay now why is

that important

okay if we know anything about gray

matter and white matter in the brain

well white matter in the brain is

essentially made up of myelinated axons

okay that's what gives it the color

white if you've ever heard of gray

matter okay in the brain

it's called gray matter essentially

because it's the color gray because

those are unmyelinated okay there aren't

any axons that have myelom so there's

some

interesting background on the myelinated

verse on myelinated now there is another

way to make this action potential go

even faster down the axon and how is

that you notice these little tiny gaps

between the mylon okay

these gaps are what we call the nodes

of

ranvier or ranvier i always see

different names for it all right so

these are these little tiny gaps in the

mylon okay do you ever take a rock and

skip it across the water and it just

goes

right these are what the nodes do right

so here's our action potential and when

you have myelinated axons instead of

going through the axon

what happens is they bounce from node to

node and this helps speed up the process

even more so instead of going through

goes bounce bounce bounds all the way to

the end of the axon all right so what is

the end of the axon

these little branches here are what we

call the axon terminal or you might say

synaptic buds there's always so many

names for all these things axon terminal

okay

and this is where let's get back to our

neurotransmitters our neurotransmitters

are stored in synaptic vesicles and

what's going to happen is once the

exponential hits there these are going

to be released

and bind to receptors of the next

postsynaptic neuron now two neurons

don't actually touch each other it's

going to be released into an area called

the synapse is a small gap or junction

between two neurons and that's going to

bind to receptor of another neuron so

there we go there's the parts or main

parts of a neuron now it is important to

note

not all neurons look the same even

though they have roughly the same parts

they could look very different so for

example this first one is what we call a

motor neuron you can see it actually is

the typical neuron that you would see if

you google something like that right

another oh another word for motor neuron

is a multi-multi-polar

neuron okay you can have let's say a

sensory neuron

okay

sensory neuron and this is actually

another word is unipolar

neuron

and you can even have something called

an interneuron

okay

and this would be considered a bipolar

neuron right so many different names and

you could find bipolar neurons in the

retina okay in your eye next to the

ganglion cells so motor neurons would

help move my muscles right afferent or

efferent that exit the brain help me

move sensory neurons detect information

from the environment right hot cold

smells and sites and interneurons

connect or help a link the motor and

sensory neurons

all right guys thanks for watching i

really hope you learned something don't

forget to like the video subscribe i'll

see you next time