Anesthesia is the source of hilarious videos gone viral, depicting dazed hospital patients waking up from operations and saying weird things. But it’s also a highly complicated and specialized aspect of medicine, sporting a long history and a significant role in many operations.

There's the kid who broke his arm at a hockey game, and is put under anesthesia at the hospital. He can't stop laughing for nearly five minutes straight, while yelling, "Oh man, everything's in slow motion!" as the serious drone of his doctors discussing his arm is audible in the background. "So weird!" the kid yells. "I see doubles of everything, rainbows everywhere. ...Actually I don't see rainbows, I don't know why I said rainbows..." His dad says, "Go back to sleep, Tyler."

There's also the video of Jason Mortensen, a man slowly emerging from an anesthesia-induced slumber post-hernia operation, which went viral after he called a woman (who happened to be his wife of six years) “eye candy.” “You’re my wife?” Mortensen exclaimed while lying in a hospital bed, out of it. “I hit the jackpot!” Another video shows a woman talking to her husband while in the hospital bed, about her experience being drugged. It’s not clear whether it’s the anesthesia talking, or if she’s just really funny.

Drug-Induced ‘Twilight’

But what really causes people under anesthesia to act like they do; what’s the science behind the feeling it induces, of drowsiness and a sense of being high? Anesthesia has been referred to as a reversible coma. In a study, researchers compared the difference between a person sleeping and someone under anesthesia, and they found that the deepest levels of sleeping are similar to the lightest anesthesia.

The term “anesthesia” stems from the Greek words for “loss of sensation.” It holds several different purposes depending on the procedure — sometimes to relieve pain, to “knock” you unconscious or to induce amnesia so you have no memory or feeling of a medical procedure, reduce anxiety, and paralyze muscles.

Anesthesia is carefully controlled. Certain doctors and nurses specialize in anesthesiology, because it’s such a complex — and highly important — part of many medical procedures. Anesthesiologists must accurately measure the exact dosages to maintain a safe drug-induced state.

Types Of Anesthesia

Depending on dosage, anesthesia has different effects on your body. General anesthesia knocks you out completely, while local anesthesia is only applied to certain body parts or patches of skin. Local anesthesia is often used during dental procedures, like when your dentist tells you, “It’s just going to be a little bug bite,” as he jabs your gum with a needle.

Scary dentist wielding tools "It's just going to be a little bug bite."

If you’ve ever had your wisdom teeth pulled, you have probably undergone procedural sedation, which is used for short and minor medical operations. Wisdom teeth pullings are also famous for leaving patients in a state of confusion post-operation. People under procedural sedation remain awake and can still answer questions, though they are typically quite relaxed and drowsy for several hours after the operation.

There’s also something called regional anesthesia, which is similar to local anesthesia but often covers a larger portion of the body and is sometimes called a nerve block.

Interestingly enough, anesthesia is linked to cocaine. Plenty of drugs used in local anesthesia end with the suffix “-aine” because they are chemically similar to cocaine (think of lidocaine or novocaine). Historically, cocaine was actually used as a local anesthetic and painkiller (analgesic), until doctors discovered that it’s highly addictive and stimulating to the cardiovascular system, and patients started dying after using it. In fact, in the 1800s, things like cocaine “toothache drops” actually existed, due to cocaine’s analgesic properties.

In the 1800s, cocaine was used medically as a painkiller.

When anesthesia begins to work on your body, it primarily affects the spinal cord, the brain stem reticular activating system, as well as the cerebral cortex. It’s usually inserted into the body through an IV injection or via gas. There are four stages of general anesthesia. In the first, which is called induction, patients begin to feel the effects but are not unconscious yet. Next, during the “excitement” phase, the patient is unconscious and may twitch or having irregular breathing patterns. In stage 3, the patient is fully anesthetized with regular breathing. Stage 4 is considered an emergency and not part of the safe process; if a patient overdoses on drugs, it can lead to brain damage or death.

Muscles become so relaxed when you’re “put under” that it’s necessary to wear a breathing mask or tube to keep airways open. It’s also important to monitor the oxygen level in the patient’s blood, heart rate, blood pressure, respiratory rate, carbon dioxide exhalation levels, and temperature.

Because there are risks associated with anesthesia, it’s important to discuss it first with your doctor before going in for an operation. After the surgery or procedure is finished, the person is often taken to a post-anesthesia care unit where they slowly recover from the effects. Though in rare occasions anesthesia has been fatal and/or caused problems, it is a highly controlled and safe (and usually necessary) aspect of medicine that will most likely just lead to funny YouTube videos anyway.