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3ESO CNS - Contenido educativo

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Subido el 25 de enero de 2021 por Marta G.

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hello welcome to a new video of this unit nervous endocrine system today we're gonna see how the 00:00:00
neurons connect one with another and they transmit the electric impulse all around our body also 00:00:07
we are going to see our central nervous system get ready starting how the neurons transmit 00:00:14
information from one to another we're gonna write the title 2.2 electric signals 00:00:32
now we're going to make a pop-up marvelous pop-up that you love here okay in our notebook we need 00:00:40
the white paper and we're going to cut a stripe which will be 30 centimeters long 10 centimeters 00:00:48
why okay the first thing we cut 30 10 and then we make a flap at about 10 centimeters from the 00:00:56
border okay so this is the first thing we need to do we have 30 centimeters times 10 and then we 00:01:07
fold at 10. here we go think that we have the information imagine that we touch something with 00:01:14
our hand and the information of that touch has to come from our fingers up to our brain and decide 00:01:23
what do we do with this touch and then come back to our arm to take it back or to grab it. 00:01:32
How does that happen? Because we have connections between neurons. How does this connection take 00:01:38
place look at this picture this is the flap that we have made i have fold this part okay this is 00:01:46
going to be the flap that will open and close okay this part will open and close you need to make all 00:01:55
this drawing about the synapse how an ear on contact with another we have first of all the 00:02:03
information imagine that we touch something we have some information that is going to get inside 00:02:09
the neuron by electric signal very important electric signal all these process is made up 00:02:16
by electric impulse so we have information coming by electricity and the information has to come 00:02:26
from the presynaptic neuron to the false synaptic neuron so it travels from the dendrites coming 00:02:34
from the dendrites, get to the cell body, down to the axon and then to the axon terminal. 00:02:43
The axon terminal is the end of the journey for disinformation into this neuron, but then it jumps 00:02:50
to the next neuron, we're going to see how in a minute, and gets to the postsynaptic neuron. 00:02:56
In this postsynaptic neuron, the impulse continues by electric impulse. This part inside is what is 00:03:03
called the synapses synapse and we're going to open this part to have all the information inside 00:03:12
we have seen how the impulse goes from presynaptic neuron to the postsynaptic neuron from dendrites 00:03:23
to the axon terminals but we're going to focus on this area the specific point where the information 00:03:30
passes from one neuron to the next how does that happen let's see what i have made is that these 00:03:38
circles that we made i have made it bigger imagine that we have an electronic microscope and we are 00:03:45
going to see this specific area so we take our flaps here imagine that we have the presynaptic 00:03:51
neuron we open it and we have this okay the circles is this one here what do we have okay 00:03:58
this is the presynaptic neuron and this is the axon terminal. So we are in this part but in this 00:04:08
neuron. And here we have the dendrite of the postsynaptic neuron. Therefore, the nerve impulse 00:04:15
comes this way, from cell body to the axon and axon terminal. So we are in the axon terminal, 00:04:25
the impulse comes and we have here some vesicles. If you remember from the unit that we talked about 00:04:31
the cells and the different organelles we said that vesicles contain some substances that could 00:04:37
be used inside the cell or released outside the cell how are they released they fuse with the 00:04:44
membrane with the cell membrane and they release their content outside the cell so we have vesicles 00:04:51
with things inside these substances these green dots are called neurotransmitters neurotransmitters 00:04:58
are different substances they could be proteins they could be lipids which cell information 00:05:07
transform the electric information to chemical information it could be for example caffeine 00:05:15
could be for example adrenaline for example if you're very nervous your adrenaline is really high 00:05:23
because you're under stress or maybe if you are doing sports for example your body thinks that 00:05:31
you are under stress and you need to rush and you need to run so your adrenaline is really really 00:05:36
high that means that in the in this part the neurotransmitters of adrenaline are going to 00:05:43
be released so this neurotransmitter are inside the vesicle they fuse with the cell membrane 00:05:50
and they are released into this space between the presynaptic and postsynaptic neuron which 00:05:57
is the synaptic cleft synaptic cleft in spanish and the dura synaptica so presynaptic and 00:06:02
postsynaptic neurons are not in touch okay they do not touch each other they have a space here 00:06:12
where the neurotransmitters are released and in the postsynaptic neurons we have some receptors 00:06:18
that are going to take the neurotransmitter and transform that chemical signal into electric signal 00:06:24
which is going then to pass to the cell body, to the axon, to the axon terminal and continue 00:06:31
and continue the journey all the time. So basically, making a summary, electric signal comes, 00:06:37
activates vesicles, vesicles release the neurotransmitter into the synaptic cleft, 00:06:46
they move to the receptor of the postsynaptic neuron and then in the receptors it transforms 00:06:50
to a nerve impulse that travels really, really fast. It takes a really short time, I can tell you, 00:06:57
really. If not, you won't be able to hear me right now, or to see me, or to think what the hell is 00:07:04
she talking about. There's still a space here. If we open this, we should be having here a space 00:07:11
which is blank, we're going to copy the definitions of neurotransmitters and nerve impulses. 00:07:20
Nerve impulses, electric changes in the membrane in order to transmit information by electric 00:07:28
signals. Neurotransmitters, chemicals which allow the transmission of signals from one neuron to 00:07:35
the next across synapses. dopamine acetylcholine. Now that we know how neurons 00:07:42
take information from one to another, let's see the different parts of the nervous system. Before 00:07:52
before you write anything on your notebook, I'm going to explain you what we're gonna do here. 00:07:59
The nervous system is very complex, has a lot of names, there are different parts of our body, 00:08:05
a different function. What we are going to do is to do a super outline. With this super outline, 00:08:11
look, I used really, really tiny writing and it took me a whole bit. So, please, take your notebook. 00:08:19
Either one thing is that you can use two pages. You open and you take the left and right side of 00:08:29
your notebook in case you need more space for example to have this outline but i want this 00:08:37
outline in one single paper i mean that i want you to have an overview of all of it i don't want to 00:08:43
have the first part of the central neural system on one page and then the peripheral neural system 00:08:52
in another page okay so i want everything on one paper as i said it could be this is the left part 00:08:59
the right the left part of your notebook and this is the right part but all that you can see with 00:09:08
one side point number three nervous system 00:09:16
let's start it we have two parts in our nervous system we have the central nervous system and the 00:09:20
peripheral nervous system today we're going to focus on the central nervous system and tomorrow 00:09:30
we'll start with the peripheral nervous system that's why i wrote it really really down on the 00:09:36
board okay the difference between central nervous nervous system and peripheral is that the central 00:09:45
receives the information and takes decision according to it according to the information 00:09:51
it receives but the peripheral nervous system is the responsible for receiving that information 00:09:56
and making the action so basically this is going to be compound of the brain and the spinal cord 00:10:02
Whereas the peripheral nervous system is going to be compound of all the different nerves in our body 00:10:13
Our central nervous system has three main functions 00:10:19
first of all integrates the information that receives if I'm talking to you is because I 00:10:24
Have a hearing and I hear that there is nothing disturbing me here 00:10:32
that I can see the camera and I know that I'm looking to the camera and I have the information 00:10:37
here with all the things that I want to tell you and all this is integrated in my brain so the 00:10:44
function is to integrate the information that received from outside the world and also inside 00:10:54
my body also to prepare our coordinate responses my response to all the information surrounding me 00:11:00
is that i'm going to talk that will be the response so integrate information and coordinate 00:11:09
and prepare responses our central nervous system is very important therefore i need to be protected 00:11:17
how it could be protected by some bones like our skull and our spine all the bones that we have in 00:11:26
our spine and our skull try to pretend to protect the central nervous system also by membranes 00:11:34
we cannot have the central nervous system in contact with the bones so we have a membrane 00:11:43
surrounding it that is called the meninges meninges that's what can cause the illness 00:11:48
of meningitis if the these membranes are inflamed because of a virus for example or because 00:11:56
of a certain illness then we can develop meningitis and it's really really dangerous 00:12:03
we have also a fluid between membrane and also the nerves that is the cerebrospinal fluid 00:12:09
which in Spanish we call it líquido cefalorraquídeo in this place in this fluid is when for example 00:12:20
we are going to go to the surgery and we need some anesthesia for example the epidural 00:12:28
epidural, anesthesia epidural, that is going to be injected here in the cerebrospinal fluid 00:12:35
inside our spine. And it's not only for pregnant women, okay? It could be to any of us could go 00:12:45
to surgery and we might need epidural. So it's very important because it's going to protect 00:12:53
the central nervous system inside our central nervous system we have two different types of 00:13:00
tissues depending well they are not really really tissues they are different parts of the neurons 00:13:08
we have the gray matter and the white matter which in spanish are 00:13:14
maybe you have here about the gray matter because if people people who are very clever have a lot 00:13:18
of gray matter. What is the gray matter? The cell body of the neurons and the dephrytes. 00:13:27
What is the white matter? The axon and the myelin sheaths. Myelin sheaths are white, therefore they 00:13:34
have that color. Our central nervous system is compound of two different parts. The spinal cord, 00:13:41
which in Spanish we call it medula spinal, and the brain, which in Spanish is encephalo. 00:13:49
yeah it's a trick that brain usually we translate it as cerebro but we do not only have a cerebro 00:13:56
inside our brain you'll see why but let's start with the spinal cord we're going to see how is 00:14:05
our spinal cord inside we're going to make this drawing you don't need to make it there usually 00:14:13
what i recommend is that you make a flap here okay you make this throw it in a separate piece of 00:14:20
paper and you will glue it later so it opens and close so it does not occupy some space of your 00:14:26
outline so what do we have imagine that we cut here ourselves in this part of our spinal cord 00:14:33
and we see it under the microscope we'll see something like that something resemble a 00:14:42
butterfly we always say that it has a butterfly shape the spinal cord we have the gray matter 00:14:48
on the outer part i was sorry the white matter on the outer part and the great matter in the 00:14:55
inner part also there is a hole in the middle which is called the penema there is where is 00:15:01
going to be the cerebral spinal fluid in our spinal cord here in the middle also out of our 00:15:08
our spinal cord get out the nerves. The nerves are going to get along our body and they are going to 00:15:16
send the information to the muscles, to the different organs to perform functions. 00:15:24
We have two functions of the spinal cord. Let's see the first one, the reflex action, reflex. 00:15:33
When we take our hand out of a fire because it's burning on, it's a matter of survival. 00:15:40
So we cannot think. 00:15:47
Rapid action of no thinking, those are the reflexion actions. 00:15:48
How does that happen? 00:15:53
Steps. 00:15:54
First of all, we're going to receive the stimulus in our receptor. 00:15:54
In this case, it would be our touch. 00:15:59
From the touch, we have a sensory neuron that comes from our hand up to the spinal cord. 00:16:01
In the spinal cord, here, in this area, comes the nerve of the sensory nerve. 00:16:09
We have an interneuron that is going to connect this sensory neuron that is coming inside with the motor neurons. 00:16:16
The motor neurons send the signal getting out of other point of the spinal cord to the effector. 00:16:24
The effector, in this case, will be my hand, and the effector produces some responses. 00:16:31
In this case, I get out of the fire. 00:16:36
Other function that the spinal cord has is to be a pathway first from sensory to the brain. 00:16:39
So if, yeah, okay, if we touch something and it hurts, we get it back. 00:16:46
But imagine that I want to grab something. 00:16:51
I need to touch it, okay? 00:16:54
So this sensation comes from my hand, it gets from the nerve to the spinal cord, 00:16:57
and then it needs to be sent to the brain. 00:17:02
so the spinal cord is going to be like a highway that is going to take these nerves 00:17:04
up to the brain and then from the brain is going to be also a pathway the highway of the nerves 00:17:10
which is going to get back to the effector so i can grab this eraser this is all for today of 00:17:20
our outline. Next day we continue with brain and peripheral nervous system. 00:17:29
Idioma/s:
en
Autor/es:
Marta Garcia
Subido por:
Marta G.
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
157
Fecha:
25 de enero de 2021 - 9:27
Visibilidad:
Clave
Centro:
IES FORTUNY
Duración:
17′ 51″
Relación de aspecto:
1.78:1
Resolución:
1920x1080 píxeles
Tamaño:
421.16 MBytes

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