How does anesthesia work?

Answer 1

a controllable and reversible loss of consciousness induced by intoxication of the central nervous system. Lowered sensitivity to external stimuli (hyporeflexia), analgesia, unconsciousness, muscle relaxation, and amnesia are significant features of general anaesthesia. The term "surgical anaesthesia" emphasizes muscle relaxation and analgesia.

Answer 2

We still do not know exactly how general anesthesia works, but modern neuroscientific research has at least suggested a number of plausible hypotheses. The most commonly accepted theory is that general anesthetics operate directly on the central nervous system to temporarily inhibit synaptic transmission (the chemical means by which neural impulses are transmitted between adjacent neurons). This results in a general loss of consciousness that affects sensory awareness in all modalities and at all body loci.

Beyond this general statement, one "nonspecific" theory holds that anesthetics impair the operation of the sodium pump, preventing depolarization of postsynaptic neurons. A more recent "dual-process model" suggests that anesthetics simultaneously inhibit the actions of excitatory neurotransmitters such as glutamate and acetylcholine and enhance the actions of inhibitory neurotransmitters such as GABA and glycine. The specific physiological mechanism by which anesthesia is achieved probably differs for each different class of anesthetic agents.

Answer 3

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We still do not know exactly how general anesthesia works, but modern neuroscientific research has at least suggested a number of plausible hypotheses. The most commonly accepted theory is that general anesthetics operate directly on the central nervous system to temporarily inhibit synaptic transmission (the chemical means by which neural impulses are transmitted between adjacent neurons). This results in a general loss of consciousness that affects sensory awareness in all modalities and at all body loci.

Beyond this general statement, one "nonspecific" theory holds that anesthetics impair the operation of the sodium pump, preventing depolarization of postsynaptic neurons. A more recent "dual-process model" suggests that anesthetics simultaneously inhibit the actions of excitatory neurotransmitters such as glutamate and acetylcholine and enhance the actions of inhibitory neurotransmitters such as GABA and glycine. The specific physiological mechanism by which anesthesia is achieved probably differs for each different class of anesthetic agents.

Answer 4

You have certain receptors in your brain that are for "excitory" molecules - ie will set off an action potential or "brainwave" if you like, and others that are "inhibitory" and do the reverse. When a brain cell (neuron) is excited, the potential (ie charge) in the cell changes from about -70mV to 10mV - it depolarises. Anasthetics generally act on receptors in your brain for inhibitory molecules - the make the cell think the inhibitory molecule is present, so the cell will "hyperpolarise" - change to about 90-100mV, making it harder for the cell to depolarise and signal to the next cell. Basically, they stop the cells communicating with each other, so you fall asleep or can't sense what is happening to you, eg pain.

Answer 5

General anesthesia is the induction of a balanced state of unconsciousness, accompanied by the absence of pain sensation and the paralysis of skeletal muscle over the entire body. It is induced through the administration of anesthetic drugs and is used during major surgery and other invasive surgical procedures.


A nurse anesthetist injecting medication into the intravenous tube of a patient during surgery. (Photo Researchers Inc. Reproduced by permission.)
Purpose
General anesthesia is intended to bring about five distinct states during surgery:

analgesia, or pain relief
amnesia, or loss of memory of the procedure
loss of consciousness
motionlessness
weakening of autonomic responses
Precautions
A complete medical history, including a history of allergies in family members, is an important precaution. Patients may have a potentially fatal allergic response to anesthesia known as malignant hyperthermia, even if there is no previous personal history of reaction.

General anesthetics should be administered only by board-certified medical professionals. Anesthesia providers consider many factors, including a patient's age, weight, allergies to medications, medical history, and general health when deciding which anesthetic or combination of anesthetics to use. The American Society of Anesthesiologists has compiled guidelines for classifying patients according to risk levels as follows:

I: healthy patient
II: patient with mild systemic disease without functional limitations
III: patient with severe systemic disease with definite functional limitations
IV: patient with severe systemic disease that is life-threatening
V: dying patient not expected to survive for 24 hours without an operation
Equipment for general anesthesia should be thoroughly checked before the operation; all items that might be needed, such as extra tubes or laryngoscope blades, should be available. Staff members should be knowledgeable about the problems that might arise with the specific anesthetic being used, and be able to recognize them and respond appropriately. General anesthetics cause a lowering of the blood pressure (hypotension), a response that requires close monitoring and special drugs to reverse it in emergency situations.

Description
General anesthetics may be gases or volatile liquids that evaporate as they are inhaled through a mask along with oxygen. Other general anesthetics are given intravenously. The amount of anesthesia produced by inhaling a general anesthetic can be adjusted rapidly, if necessary, by adjusting the anesthetic-to-oxygen ratio that is inhaled by the patient. The degree of anesthesia produced by an intravenously injected anesthetic cannot be changed as rapidly and must be reversed by administration of another drug.

The precise mechanism of general anesthesia is not yet fully understood. There are, however, several hypotheses that have been advanced to explain why general anesthesia occurs. The first, the so-called Meyer-Overton theory, suggests that anesthesia occurs when a sufficient number of molecules of an inhalation anesthetic dissolve in the lipid cell membrane. The second theory maintains that protein receptors in the central nervous system are involved, in that inhalation anesthetics inhibit the enzyme activity of proteins. A third hypothesis, proposed by Linus Pauling in 1961, suggests that anesthetic molecules interact with water molecules to form clathrates (hydrated microcrystals), which in turn inhibit receptor function.

Answer 6

Anaesthesia, loss of sensation, especially the sensation of touch. It can be general (affecting the entire body and usually accompanied by loss of consciousness) or local (affecting limited areas of the body). The condition may be the result of damage to nerves or nerve centres (seeNervous System) by disease or injury, or it may be intentionally induced by the administration of drugs for the prevention or relief of pain.

*Nervous System, those elements within the animal organism that are concerned with the reception of stimuli, the transmission of nerve impulses, or the activation of muscle mechanisms.
The reception of stimuli is the function of special sensory cells. The conducting elements of the nervous system are cells called neurons; these may be capable of only slow and generalized activity, or they may be highly efficient and rapidly conducting units. The specific response of the neuron—the nerve impulse—and the capacity of the cell to be stimulated make this cell a receiving and transmitting unit capable of transferring information from one part of the body to another.

Answer 7

It puts your brain to sleep via your nervous or circulatory system.

Answer 8

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Answer 9

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Answer 10

It "jams" the conection between neurons in the nerves.