Okay, so what's a plexus? Yeah, I'm not talking about a pink drink.
I'm talking about a plexus in your spinal cord. Now we're talking about the brachial plexus.
The plexus is a network or a tangle, might be a better word, of lymphatic vessels, nerves and veins.
So when you hear health care providers refer to the brachial plexus, that's what they are talking about.
It's a network or a tangle of lymphatic vessels, nerves or veins.
Okay, now, CSF, cerebrospinal fluid is constantly being produced
by the choroid plexuses inside the ventricles of the brain.
Now, we've got a great picture for you here and so always if someone includes a picture take the time to really look at it and study it.
So what I want you to do now is to pause and look for the choroid plexus.
You don't have to pause the video if you can find it right now
but I wanna make sure you put your finger on the choroid plexus before we go on.
Okay, so link the concept of cerebrospinal fluid and choroid plexus together
because that's where the production of cerebrospinal fluid happens.
Now most of the cerebrospinal fluid will drain from the ventricles into the what?
Sweet, the subarachnoid space around the brain and the spinal cord,
so take your finger, find the subarachnoid space
and I want you to trace it all the way around the brain down to the spinal cord
so you're really using your fingers as a way to learn and imprint information into your own brains
because anytime you use motion or touch you're really helping your brain encode.
So find the choroid plexus, boom.
Find the subarachnoid space, trace it all the way around there
so we know that the CSF is produced in the choroid plexus inside the ventricles of the brain
and most of the cerebrospinal fluid drains from the ventricles into the subarachnoid space around the brain and spinal cord.
Now you have a real picture in your mind of what that looks like
when we are talking about the subarachnoid space, that's in-between those meninges that we've talked about, remember?
Pia, arachnoid, dura -- you've got it, good.
So subarachnoid is just below, sub, the arachnoid layer.
Now a little bit of it flows down that central canal of the spinal cord.
Can you picture in your mind where that is?
Yeah, that was that hole dead in the center or canal dead in the center of the spinal cord in the gray mater.
Now it constantly drains to the dural sinuses to the arachnoid villi also,
so predominantly subarachnoid space is gonna get the most of it
but a little bit is gonna go down the central canal and it's also through the arachnoid villi.
We talked about cerebrospinal fluid and the spinal cord, a layer of cerebrospinal fluid protects the spinal cord,
remember, we talked about that -- you had the cerebrospinal fluid and the fat but I want to hit it one more time.
The cerebrospinal fluid protects the spinal cord in the subarachnoid space.
It helps it from getting damaged by coming into contact with that interior side of the column.
Okay, so that acts as a cushion just like the fat disc,
the cerebrospinal fluid also acts as a shock absorber and a cushion.
Now, let's take a look at the peripheral nervous system.
Remember, the central nervous system goes right down the dead center of your body.
The peripheral nervous system are those nerves that connect the spinal cord to the rest of the parts of your body,
it's called the peripheral nervous system.
Now we use that word a lot, like peripheral IV, right, versus a central line.
So think of the nerves, peripheral nervous system is everything coming off the spinal cord out to the rest of the parts of your body, okay?
So we'll talk about peripheral nervous system medications versus CNS medications.
You'll see us use these terms, peripheral nervous system and central nervous system a lot in health care.