- [Voiceover] As we're finishing up
this section on the central nervous system,
we need to look at some drug interactions
and some disorders.
Now, psychoactive drugs,
what they're actually doing
is affecting your state of consciousness,
emotions, behaviors, because they're interacting
with the neurons and cause the neurons
to either fire faster, to fire slower,
or to completely misfire creating different perception.
Now the reason they're active is they can
actually go across the blood brain barrier.
Now, these higher brain functions
that are affected can be anywhere from perception
of reality to balance to emotion to anything really
in the brain can be affected.
So as they change the way that the actual neurons
are working, they're dealing with how
the neuron transmitters are being released.
By releasing more neurotransmitter
you can actually cause an increased reaction of neurons,
or releasing less neurotransmitter.
They might even completely stop neurotransmitter activity.
So it all depends on which ones are being affected,
which neurotransmitters that is,
and how they're affected,
as far as what will make a difference
in your consciousness, your emotions,
or your behavior, or all three together.
Now these psychoactive drugs
can cause psychological dependence.
A lot of times after using,
the users will crave that feeling again.
They'll want to go back to wherever that place was,
or whatever that feeling was.
The problem is then once they start doing that
they start to build up a tolerance.
So to be able to achieve the same level of feeling,
they have to increase more and more of the drug each time.
And by continually increasing the amount of drug,
all they're doing is maintaining
the same psychoactive feeling.
Problem is your body will not stop.
The tolerance keeps building,
you keep having to put more and more into the system.
Now this is pretty much your common addiction.
It's the person need, a physiological or psychological
aspect, their need to use a substance.
Maybe you're saying that, you don't take drugs,
so you're saying "Okay, fine, never had problems,
"I don't know anyone that has a problem with this.
"So it's a choice, why not make a free choice?"
Well it's not really a free choice.
The person's body is screaming at them
to have more of this psychoactive drug.
To go back to that same feeling.
Some of the physiological reasons sometimes
is certain drugs start to replace neurotransmitters.
So without the drug in the system
the person's actually having fewer
neurotransmitters than normal.
By using the drug, they're just going back
to a normal state of nervous activity.
Well, in cases like that it's not really a choice.
Without using it the body's not functioning properly.
Now are there ways to reduce or eliminate addiction?
Sure, there's different treatments,
different medications, different types of methods
that could help out.
But for pretty much any addiction
the person that's addicted must want to do it.
Doesn't matter how many people tell them,
how many people are showing them the problems,
if they truly don't want to go off the drug,
no course of treatment is gonna help.
And under any time they're getting off addiction,
withdrawing, the physical symptoms
can range from mild, maybe a little discomfort,
a little nausea, to extreme, complete vertigo,
cold sweats, fevers, wracking chills
throughout the body.
So there can be some very minor
to very major withdrawal effects.
It depends on how much the drug the person was used to
and what drug it is.
To start off our disorders we're looking at trauma.
Now, trauma's a pretty general term.
It's any physical injury to the brain or spinal cord.
One type is a concussion.
In a case of a concussion, it says your blow
to the head may lead to unconsciousness, true
but this blow to the head could be from a blunt object,
like a baseball bat, could be a sharp impeding blow
from a knife.
But any impact to the head that causes damage
could result in concussion.
So besides the fact of being knocked unconscious
you might have a disruption in the electrical activity
of the brain.
Well if you disrupt electrical activity,
that means your memory might also be affected.
So even if you weren't rendered unconscious,
you're still conscious looking around,
10, 20 minutes later you might look back
and say "I have no idea what happened
"for these five minutes."
Just completely blank in your mind.
There also is the risk of a subdural hematoma.
Subdural hematoma is a build up of blood
under the durma, so in the subdural space.
Now this subdural hematoma could be very dangerous
because it could apply excess pressure to the brain.
Now does every impact to the head
cause a concussion?
No, does every concussion knock a person unconscious?
No, so there's varying degrees
from very mild to very severe concussions.
Moving down to the spinal cord,
there's different spinal cord injuries.
So if you have an injury in the spinal cord,
if you have an impairment,
if you have a pinching, a severing,
well anything that's below that point,
so for example, there's an injury in the thoracic region
of the spinal cord.
That's right where your rib cage is.
That would mean that you potentially might
have enough of an impairment where you lose
all sensation and function below that point.
That means your hips, your waist, your legs
would not respond, they would not be functional.
So spinal cord injuries, brain injuries, concussions
all are pretty severe injuries and problems.
But how 'bout the infections?
Well we could look at a virus or a bacteria,
all depends on what is actually being affected.
In the case of encephalitis this is a viral
infection causing inflammation of the brain.
Now in a new born it's not quite as problematic
but in an adult, could be very problematic.
The difference is in a new born,
their skull is not held together yet.
So an increase in pressure or inflammation
would simply push the bones of the skull outward.
Where in the case of an adult,
those bones are solid, you're not pushing them out.
So if inflammation occurs, if you can't push out
that means you're pushing in.
Into the brain.
Meningitis, now this is inflammation
of the meninges around the brain
or sometimes the spinal cord.
Remember the meninges are those three layers
of connective tissue.
So we're trying to protect the brain
but can also cause an infection of the brain.
Now it could be viral meningitis
or it could be bacterial meningitis.
Rabies, lot of times you think of rabies
as an infected animal.
Well that's what spreads it.
But this is a viral disease.
It can spread from the bite of anything infected,
an infected animal, could be a person that is infected
and it'll travel from that infected bite
up to the brain.
It travels through these sensory neurons
what's carrying the information back to the brain.
So, rabies viral infection that is heading to your brain
once it enters the system.
Then we have brain tumors.
Now brain tumors could be benign, without cancer,
or they could be cancerous.
But in general a brain tumor is any abnormal growth,
anything that's growing unusually
and usually when something in the brain
is growing abnormally, it's putting pressure
on something that shouldn't be pushed.
So if all it's doing is putting pressure
on the wrong spots, whatever is being forced
or pressured could potentially lose it's functionality.
Some more disorders, epilepsy.
Now in epilepsy it's usually a recurring
episode of unusual or abnormal electrical activity.
It's a fancy way of saying recurring seizures.
Alzheimer's disease, in the case of Alzheimer's
the patient does not have enough acetylcholine.
So what ends up happening
is we end up accumulating some abnormal proteins,
we have more progressive memory lapses,
dementia kicks in.
The person just really has a problem
processing, understanding, and remembering information.
All because that neurotransmitter acetylcholine
isn't in high enough quantities.
Parkinson's, well in the case of Parkinson's
you're losing your dopamine releasing neurons.
Now dopamine is gonna be a type of neurotransmitter.
What ends up happening in Parkinson's disease
is you slowly and continually degenerate
any of the motor activities.
So this is gonna cause problems with movement,
gonna cause problems with control of limbs.
So Parkinson's disease, do you know what?
Dopamine causing the problem.
So here we have a nice brain image.
The one on the left, A, nice healthy brain scan.
The one, the B, is showing Alzheimer's disease.
Can you notice there's a lot more blue and black
in the Alzheimer's disease's patient's scan.
Well that means there's less activity,
less functioning inside that brain.
Less functioning, well that means
that is not simply able to process as much as efficiently.
So the healthy on the left, the letter A,
Alzheimer's on the right, not as much functional
patterns in the brain.