Going to finish up this section by talking about a few more types of neurotransmitter receptors. So we're going to begin with muscarinic receptors. Now these are another type of cholinergic receptors so they respond to acetylcholine and these can be found at all parasympathetic target organs. And these are also present in the sympathetic system, but they're really only present at sweat glands. So they're not particularly prominent in that sympathetic division. They are really prominent in that parasympathetic system. And then we have our adrenergic receptors that respond, of course, to norepinephrine and epinephrine. And these will be very commonly found at sympathetic target organs and we'll see that in the image in just one second.
Now there are two subtypes of adrenergic receptors. We have alpha receptors and beta receptors and there are subtypes of alpha and beta receptors as well. We're not going to cover that in detail in this video but do make sure that you are aware of what your professor wants you to know.
So, scooching down to our image, you can see we have all of these receptor sites. All these synapses now have highlights. We still have all of those green highlights; those are our nicotinic receptors. You can see that those are present at all the synapses between pre and postganglionic neurons there. And we're going to start over here on the parasympathetic side looking at all of these yellow highlighted receptor sites and those are going to be where our muscarinic receptors are present. So remember, those are a type of cholinergic receptor; they're going to be responding to acetylcholine and of course that makes sense because we have all of these little postganglionic cholinergic fibers there that will be releasing acetylcholine into those synapses. So you can see all of our target organs on that parasympathetic side have those muscarinic receptors there in yellow.
Looking at our sympathetic side, you can see we have these pinkish purple highlights on most of our sympathetic target organs and those are going to be our adrenergic receptors. And you can see we do have a couple of exceptions here. You can see on the skin we have that muscarinic receptor and then down here on the adrenal medulla we have that nicotinic receptor like we talked about last time. You can see how the majority of these are going to be adrenergic and, of course, that makes sense because all of these adrenergic fibers, all these postganglionic adrenergic fibers, are going to be releasing norepinephrine and epinephrine, so those target organs have to have receptors that can bind to those neurotransmitters.
Alright. So that is our section on neurotransmitters and I will see you guys in our next video. Bye bye.