Learn how the nervous system produces behavior, how we use our brain every day, and how neuroscience can explain the common problems afflicting people today. We will study functional human neuroanatomy and neuronal communication, and then use this information to understand how we perceive the outside world, move our bodies voluntarily, stay alive, and play well with others.
Meninges
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來自 The University of Chicago 的課程
了解大脑：日常生活中的神经生物学
624 個評分
從本節課中
The Nervous System
Neurobiology is a rapidly growing area of scientific research, and is becoming increasingly prevalent in the news and popular culture. In this course, we will study of the nervous system from a biological perspective by exploring the fundamental concepts in neurobiology, including how we sense the world, how we act in the world, and common neurological disorders.
與講師見面
Peggy MasonProfessor
Neurobiology
[MUSIC]
So, we're going to talk now about the difference between
the Central Nervous System and the Peripheral Nervous System.
There's a barrier,there's a fence, and that
fence is the demarcation between central and peripheral.
And that fence is made up of three
membranes, and those three membranes are the meninges.
There are three meningeal layers, and the three layers
go from very weak, very tender, the pia, to very
tough, the dura and, in between, there's a spidery
thing called the arachnoid, a spidery layer called the arachnoid.
So, let's just look at what that looks like.
We're only going to see the arachnoid in, in this next picture.
So here, this is the brain, and what's covering the brain here, up here
is pia and you can't see it, it's so thin, and so tender that we don't see it.
But in this view, the dura has been removed and now we're looking down on this
film, it's a, it's an actual membrane, and that membrane is the arachnoid.
So, the different meningeal layers have different purposes, different functions.
The dura is the, is a tough sack, and that is
what's going to keep us from having concussions all the time.
All right, so it's going to float our brain in in fluid
and prevent it from banging about, and, and actually getting bruised.
It takes a hard hit to actually injure the brain,
and hopefully we, we don't have, we don't incur that.
Okay, so the meninges go from, pia is closest to the central nervous
system, is closest to the brain and spinal cord, and then dura is farthest away.
And their, all the neurons, almost all of the neurons in the central nervous
system, 200 billion minus something less than
100,000 are contained completely within the central neurons.
The only neurons that leave the central nervous system,
are these neurons that, that serve a motor function.
They actually go out the meninges and they go into the periphery.
In the periphery, there's the peripheral nervous system,
and there's also every, the rest of the body.
So there are motor neurons, they go to skeletal muscle, the
voluntary muscle, so that we can move our arms and our legs.
And these are motor neurons.
And then there are Motor neurons that go to Autonomic Neurons that control our
glands, that controls the cardiac muscle, they control our gut, smooth muscle.
So for instance, these are going to be, these neurons are what is
going to be active when you see food and you start to salivate.
Well, somebody's got to tell that gland to start salivating and
it's the brain and it does it through this two neuron chain.
So, those are Autonomic Neurons.
In addition to the motor neurons that carry information from the
central nervous system to the peripheral nervous system, there are sensory neurons.
And these sensory neurons are peripheral.
They are located peripherally, and they
carry information into the central nervous system.
What you'll note is we call a neuron either
or sensorial or peripheral based on where the cell body
is not based on where its axon is or
its dendrites, but based on where the cell body is.
So these Peripheral Neurons include Sensory Neurons and
Autonomic Neurons, these are in the autonomic ganglia.
The consequence of that is that these neurons share vulnerabilities.
The, the, they share with each other but not with the central neurons.
So, for example, there's a disease called Congenital insensitivity to pain.
People with this disease suffered a mutation in
one of a number of developmental, developmentally important genes.
And what it did was it, it, prevented a group of sensory neurons
from developing, those sensory neurons that respond to injury.
So, these people are insensitive, they never
feel pain, because they can't, they don't have
the sensory neurons that will respond to noxious
stimulation which is what usually brings us pain.
But in addition, there's a group of
the Autonomic Neurons that also developmentally got
knocked out, and these are the neurons that lead you to be able to sweat.
And so, people with Congenital insensitivity to pa, to
pain often have what's called anhydrous, meaning they can't sweat.
Those seem like two completely weird symptoms to put
together, but they're not weird because they make complete sense.
Both of them are due to a
developmental abnormality in the peripheral nervous system.
So, in the next segment what we're going to do is, is look again, look a
little bit more closely at other diseases that preferentially affect either the
periphery or the central nervous system.
[MUSIC]
