How does anesthesia work? What happens when you go ‘under’?
In: Biology
[They don’t actually know.](https://www.newscientist.com/article/mg21228402-300-banishing-consciousness-the-mystery-of-anaesthesia/)
We know that it works, but we don’t know exactly why.
Did you know that the same sort of stuff they use on humans will essentially do the same thing to plants? You can anaesthetise a Venus Fly Trap, and it will stop responding to a fly walking into it. The plant is not harmed in any way, and the anesthetic will wear off like it does in humans.
Well, depends on what medication(s) are used to put you under anesthesia. The IV kind are mostly all about a chemical called GABA. It is the inhibitory chemical that causes a suppression effect. This is where membrane polarization and a few other concepts go way over this explanation. GABA is like a light switch and we simply turn things off with it. Now, there is Ketamine which works a different way on a different system, but it basically disconnects our brain from reality and a lot of sensory input and motor output. The anesthetic gases are interesting because we do not have a complete understanding of how they work at a cellular to molecular activation. We have some extremely well thought out theories, but not that last component like the IV meds.
Now to answer “what happens” is also not exactly a fine science either. You lose consciousness, the sensory and motor relays through your spinal cord are slowed and don’t transmit as well. The central input in your Thalmus also just ignores a lot of signals from those spinal nerves too. Your nerves still send signals about pain and what not, but your brain simply never processes them. Your blood pressure goes down some, or a lot, depending on dose and age and other factors. Your heart rate slows down some as well. Breathing can be stopped or may continue depending on the medication.
An interesting factor here is that systems do not respond equally to anesthesia. People generally do not lose control of their bowels or bladder which is strange taking that most other muscle relax. This is due to autonomic control (the nervous systems that control our BP and heart rate and digestion without us thinking about it) are still mostly working just fine. Even though other nerves get their signals blocked or reduced, the autonomic system does not to the same degree.
Some reflexes are basically absent and others remain as well. A good example is if things touch your vocal cords this causes them to protect their airway and make you cough to clear it. Most under anesthesia do not do this, however, passing the breathing tube down a little further and touching the carina (the bottom part of the trachea where the lungs are divided left and right) will cause a cough reflex in many people.
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