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PHYL 141 | Nervous System | Epinephrine & Norepinephrine; Parasympathetic Neurotransmission

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All right so what are epinephrine and norepinephrine so we didn’t cover norepinephrine a little briefly but let’s talk about these more so the thing is that epinephrine is actually derived from greek root words whereas nora thing is that adrenaline is actually the same the same thing adrenaline you might actually be familiar with like when you hear about getting

Adrenaline rush or with something that’s exciting or something that’s intense so adrenaline comes from latin and the interesting thing is that they both not only are the same chemical but they both mean the same thing so adrenaline means is the latin forming above the kidney same with epinephrine like epi meaning outer and above so nephron refers to the kidney

So it’s saying above the kidney so norepinephrine is the same thing as nor adrenaline so again epinephrine is the same thing as adrenaline but again this is where you have to be very very careful norepinephrine is not the same thing as epinephrine they are two different chemicals they’re related they’re similar but they’re not the same so the thing is that

Norepinephrine if you look at the chemical structure right here don’t worry about memorizing the structure again some of you haven’t had even chemistry much less organic chemistry but epinephrine it has a it’s a different structure it has this methyl group right here so they’re not the same chemical they do not have the same binding they do they don’t activate

These receptors at the same level or have the same intensity of their effects so they are different despite looking very same and being very similar in their name actually they’re both derived from dopamine that’s the interesting thing too okay so then talking about these receptors so alpha adrenergic receptors there are two types alpha one and alpha two and

Beta adrenergic receptors there are three types again your at least the martini book puts it as a footnote but this is a thing epinephrine and norepinephrine can theoretically or they do bind to all of these so if you release a bunch of epinephrine into your circulatory system or norepinephrine it’s going to hit all of these receptors now to show it visually again

If you use if you like that sound being mnemonic don’t think the bean part is exclusive here we have epinephrine norepinephrine again similar but not the same here we have the five type of alpha and beta adrenergic receptors epinephrine can bind all five of these receptors so can norepinephrine is not exclusive so again that being immon mnemonic refers to just all

Of this taken together it’s not an exclusive one-to-one relationship and this is okay so for knowing where these are so the interesting thing with alpha one receptors what they do when you have an alpha one receptor on a blood vessel what it does is causes the blood vessels to constrict so a mnemonic you can do with your hands so you feel well i have to kind of do

This because i have to mirror it so if you have alpha and you have one and then it constricts alpha-1 constricts the blood vessels and then alpha two so let’s see or actually now let’s go to parasympathetic neurotransmission so now let’s talk about the preganglionic urine neuron and the postganglionic neuron so again both the sympathetic and parasympathetic they

Have preganglionic and postganglionic now what we have here with b2 at this synapse between the preganglionic and postganglionic is surprisingly the same thing remember these are not going to cross react because the ner the nerve fibers for sympathetic are not the same foot nerve fibers and spinal nerves as the parasympathetic nervous system but this is easy so

Between the pre-ganglion postganglionic whether it’s sympathetic or parasympathetic you have the preganglionic releasing acetylcholine this binds to nicotinic receptors this cut activates and causes action potentials in the postganglionic neuron which releases acetylcholine and this binds to muscarinic receptors so it’s actually compared to the sympathetic part is

Much more complex than the parasympathetic parasympathetic is pretty easy so what do you have the same neurotransmitter in both you just have different receptors on at different synapses so the mnemonic for this is pan am so p sorry meaning parasympathetic and this and part referring to this synapse right here where you have acetylcholine activating the ketonic

Receptors and referring to the acetylcholine binding to muscarinic receptors between the ganglion neuron and the affected and target slash target organ all right so nicotinic and muscarinic so the thing is that if you you might be like hey nicotine nick sounds like nicotine and yeah that’s how they initially discovered this receptor they found that nicotine from

Like from tobacco activates this receptor so nicotine is a ligand for nicotinic receptors acetylcholine is also a ligand for nicotinic receptors and muscarine actually i believe it comes from some sort of some species of mushroom they have a compound that came from that they found that activate the receptors but in your parasympathetic nervous system the natural

One that activates these receptors are both acetylcholine so nicotinic receptors are many diverse types do not worry about it for this class if you’ve taken a cell molecular biology class of your senior there are many of these protein subunits it gets very complex don’t worry too much muscarinic receptors there are multiple types there are five types but i think

That’s more appropriate knowing the difference between the five types is more appropriate for maybe your advanced anatomy and physiology or nursing classes but this is a what i definitely want you to know they both are found in the parasympathetic nervous system they both bind to acetylcholine

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PHYL 141 | Nervous System | Epinephrine & Norepinephrine; Parasympathetic Neurotransmission By doctorj808 – Anatomy \u0026 Physiology (A\u0026P) with Dr.J