Let's help clear this up a little bit. Let's look at how neuromuscular blockers work. Okay, so
how do they do it? We've got a great graphic for you there. We've numbered the spots just
to kind of tie this up, so you recall what we're talking about. When we say the neuromuscular
junction, that's where the nerves and the muscles come together. Now, neuromuscular
blockers cause extreme skeletal muscle relaxation. That's a nice way of saying paralyzed.
Okay, so you got the drawing there. You see that you have number 1, that's the axon. Right?
So that's not at the body of the neuron, that's coming off the axon, then number 2 you got
that motor endplate, number 3 is the muscle fiber, and number 4 are the myofibrils. So, how
the nerve tells the muscle what to do happens right in that neuromuscular junction, the area in
between the nerve and the muscle. But the neuromuscular blockers they antagonize or they
block things. That's why we call them blockers. They stop or prevent acetylcholine from
activating nicotinic M receptors at that junction. So, you want to make sure that you write in
on your notes nicotinic M receptors. Okay, so those are the receptors that are involved.
Acetylcholine is usually the neurotransmitter that activates nicotinic M receptors and allows
me to do voluntary movement with my skeletal muscles. When I give this medication, a
neuromuscular blocker, it stops acetylcholine from activating the nicotinic M, is for muscle,
receptors at this junction. So, when they're blocked, I can no longer control my skeletal muscle
which is easy with my arms, but remember the diaphragm is also skeletal muscle, so even
though that can run while I'm sleeping, I don't have to always think about it, it's still skeletal
muscle. So, let's break that down just a little bit because this is some really important concept
for you to understand. Now, look at we've taken that big picture that we just talked about,
and we're focusing in on a small square. You'll see that we've blown it up for you. Now,
number 4 is the actual nicotinic acetylcholine receptors. You highlighted that on the last slide.
Now, receptors are just polypeptides, and they respond to neurotransmitters. The
neurotransmitter in this case is acetylcholine. Now, number 5 is the one that everybody
remembers from junior high, right? Mitochondria, they are the cell's powerhouse. So, that's
how it gets their energy because they are the ones that generate most of the cell's supply of
chemical energy known as ATP. Okay, so we've gone over the neuromuscular junction. You've
got that there is the axon, it's coming off the body. Then we have the space where the neuron
and muscular junction where they come together, the nerve and the muscle. Acetylcholine is
the neurotransmitter that activates the nicotinic M receptors that allow me to move my
muscle. Neuromuscular blockers block that activity. So, when we talk about skeletal muscles.
We know that they're muscles that are attached to the skeleton. That's where they get their
name. Now, the fibers are kind of striated in appearance. It's not kind of striated. They are
striated in appearance, and they're under voluntary control. That's what makes skeletal
muscle skeletal muscle. Now, the diaphragm, we already introduced you to that, but I want to
make sure this is very clear for you. The diaphragm is also a skeletal muscle. Now, it stays at
the base of your chest, and it separates the abdomen from the chest. So, my heart and lungs
are above the diaphragm. All my intestines, liver, stomach, all those organs are below. So,
it's kind of a dividing line in my abdomen. So remember, it's a thin skeletal muscle. It's essential
to breathing, and if a patient is paralyzed with a neuromuscular blocker, they won't be able
to breathe on their own. Okay, I know we have hit that concept over and over and over again,
but it is life threatening if you're not on top of that. So, I want to make sure that you're really
aware that the diaphragm is the worst case scenario for a neuromuscular blocker if the
patient didn't have ventilator support.