General anaesthesia
General anaesthesia is a state of controlled unconsciousness.
During a general anaesthetic, medicines are used to send you to sleep, so you're unaware of surgery and do not move or feel pain while it's carried out.
Anesthesia works by blocking signals in the nervous system.
The nervous system is made up of the brain, spinal cord, and nerves.
Messages from the body travel through the nerves and spinal cord to the brain.
Anesthesia blocks pain messages from getting to the brain.
A patient who gets general anesthesia is completely unconscious (or "asleep").
They can’t feel any pain, are not aware of the surgery as it happens, and don’t remember anything from when they are “asleep.”
Patients can get general anesthesia through an IV (into a vein) or inhale it through their nose and mouth.
A tube placed in their throat helps the person breathe while they are under general anesthesia.
Excitatory and inhibitory neurons
There are two main categories of neurons in the brain.
The first are what we call “excitatory” neurons, generally responsible for keeping us alert and awake.
The second are “inhibitory” neurons – their job is to regulate and control the excitatory ones.
In our day-to-day lives, excitatory and inhibitory neurons are constantly working and balancing one another.
When we fall asleep, there are inhibitory neurons in the brain that “silence” the excitatory ones keeping us awake.
This happens gradually over time, which is why you may feel progressively more tired through the day.
General anaesthetics speed up this process by directly silencing these excitatory neurons without any action from the inhibitory ones.
This is why your anaesthetist will tell you that they’ll “put you to sleep” for the procedure: it’s essentially the same process.
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