How are our bodies able to differentiate between cuts, burns, punctures, bruises, scratches etc through pain and how do they heal differently?
In: Biology
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Note: I am intentionally oversimplifying, per the sub.
Your nervous system has different kinds of cells that sound different kinds of alarms. Some of these alarms tell your brain to experience a burning sensation (capsaicin in peppers, and alcohol in a wound trigger these), some signal sharp pain like pinches/stabs, and some signal pressure (ranging from swelling to crushing). Having either one or more of these alarms going off, how intensely, and how many are going off can help your brain understand how much trouble your body is in. The healing process isn’t qualitatively different across these different kinds of damage. As someone else commented, a cell either dies or it doesn’t, and inflammation and processes of cleaning up dead cell chunks take place. The pain signaling cells themselves can die and be regrown, but they can take a while.
This is ELI5 so I won’t get into a ton of details. Essentially, on a cellular level the damage from all of those things is similar and ends up having similar effects. Remember the powerhouse of the cell? If those injuries are severe enough it shuts down the mitochondria and then the cell dies. There are then a specific set of steps that happen after that cell death called inflammation that cause those dead cells to be cleaned up and the area repaired. Depending on the amount of initial damage the repair can be easy or hard, and scars may form.
Physical phenomena are detected by protein in cells of an organism. They signal to other proteins that leads to biological interactions which result in a cellular response. This is coordinated across multiple cells termed tissue.
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It’s a different view on the cellular level. As a structural cell, you expect to have structural connections to your neighbors, flow of intracellular fluid and stuff dissolved in it, and all sorts of material delivered through blood, even if nowhere near a major blood vessel. Cells along membranes expect some normal level of pressure and flow of various materials permitted through the membrane.
Damage may mean a cell is now exposed to outside air, structural elements broken, unusual pressure or even collapse due to rupture, changes in the flow of chemicals (nutrients, hormones, all sorts of signaling molecules, etc.), neighboring cells acting differently.
Many cells may perish from the abnormal conditions. Surviving structural cells will try to reattach to neighbors, or split apart to build new ones. Various cells in your bloodstream will react as necessary: platelets to mend breaks, macrophages to deal with foreign material, release of histamines to increase fluid flow and attract immune response. The cells will keep responding until the unusual conditions are no longer present, even if they can’t perceive that their region of the body has been bludgeoned or seared or scraped.
Different types of pain -> different types of skin receptors (free nerve endings, nociceptor, pacinian,etc)
Healing is generally done the same regardless of injury. Inflammation brings oxygens, nutrients, and different cells, including white blood cells, to the injury that clean up and help regenerate the site. Cells also send signals to each other to prevent from overgrowing. Cells that ignore these signals lead to tumors (cancer).
So this is really cool actually. As far as different feelings of pain:
Our body has different receptors on nerves that tell our brain what is going on. So we have something happen to us like a cut, those nerves get stimulated and tell our brain.
So for example, the way we tell temperature is through “thermoreceptors”. These nerves are activated by heat. Something really cool is that we have thermoreceptors in our tongue that can tell we are eating something hot like coffee or hot pizza. When we eat spicy foods, they actually activate those SAME thermoreceptors which then we perceive as “hot”.
We have other ones like “mechanoreceptors” which detect stretching or “nociceptors” that detect pain that all give our brain a good idea of what’s going on.
As for healing:
As soon as there is damage, our body responds by stopping any bleeding that’s caused and getting immune cells over to the area to try and fight any dangerous microbes that could get in from the injury. This is call inflammation.
Your body will also direct growth of new blood vessels into the area in order to bring in nutrients and other things that the still living cells can use to divide and replace all the cells that had died. By doing so our body is able to heal itself by replacing dead cells with new ones.
That was a bit long and I hope it was at least a little helpful. I’m still just a medical student but this kind of stuff is super cool to me. If I’ve made any mistakes let me know!
The difference is in the types of injuries themselves. The body just does it’s best to heal.
A few things:
1. Depth of injury. Injuries to different layers of skin feel and heal differently. I’ll spare the anatomy lesson, but a paper cut disappears after a week with no scarring but hurt like heck. Really deep injuries won’t hurt if the nerves get wrecked, but can take ~3+ weeks to fully close before leaving scars. And it’ll never feel quite the same again because things like nerves typically don’t regenerate. There’s some fantastic charts about this online.
2. Continuous wound surface area. Missing skin regenerates using progenitor cells found at the base of each hair follicle. The new cells can only travel a certain radius from their starting point, so small puncture wounds can look much nicer when healed than larger scrapes. Side bar: as someone who’s always tripping, I’m veryyy wary of laser removal of leg hairs.
3. Type of insult: Not sure how these might FEEL different, but different insults def bring their own specialties to the injury game.
1. Burns bring damage over time (wounds get larger if the “i’m in danger” zones can’t be saved), inflammation (very painful), dehydration (impairs healing), and massive infection risk (bugs love cooked tissues).
2. Bruises are focused on capillaries/blood vessels/iron-related oxidative damage (colorful!).
3. Cuts/scratches/punctures are weak to harboring debris/contaminants/bacteria which can extend the pain, impair healing, and cause scarring. Plus they can be deceptively deep — be careful folks!
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