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_AlreadyTaken_ t1_j86b9tx wrote

Reply to What are some of the mechanisms behind why long term physical inactivity and social isolation leads to chronic health diseases? by [deleted]

Isolated people tend to ignore their health in general. Married couples will have a 2nd person who will encourage them to take care of themselves and get things checked.

https://www.webmd.com/a-to-z-guides/news/20191010/marriage-tied-to-longer-life-span-new-data-shows

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7452000/

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_AlreadyTaken_ t1_j7bk0hu wrote

Reply to comment by Ech_01 in What causes the onset of puberty specifically? by Voomit

I've been fascinated by fetal development and cellular signaling and it is brutally complex when you get down to the level of cellular receptors and signaling cascade chains, dna expression, etc. You have signals signaling signals, hormonal triggers, electrolyte triggers (i.e. calcium) and multiple pathways, feedback loops, etc. I'm amazed these all function and we are alive when you look at it all.

I wonder how many of these systems are really necessary and just reflect the random progression of evolution or do they represent a hardiness that comes from redundancy?

To develop medications that work on one of these pathways is a huge challenge. You'd not only have to track the ramifications of modifying the pathway but how all the other ones and various feedback systems would respond in kind. On top of that you can have the same receptors and signaling proteins used for different systems around the body, they are only differentiated by cell type and physical isolation (diffusion limits), so you can't just pump a drug into the blood stream without affecting "innocent bystanders" (i.e. serotonin drugs).

One more thing, it is amazing how much is controlled by the hypothalamus and brain stem, the most primitive parts of the brain. It must reflect its early origins and how basic these systems are. The cerebellum and cerebrum, by virtue of their external physical locations, can grow or modify more freely without much limitation but the hypothalamus and related structures, have to pretty much stay constant in their basic structure and functions. It is surprising to see that a cluster of neurons (KNDy) would be behind this process but I really shouldn't be. It is no coincidence the pituitary is so closely linked physically and chemically to that region.

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_AlreadyTaken_ t1_j475383 wrote

Reply to comment by ThatOtherGuy_CA in When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

Your brain does this with the blind spot in your eyes (where the retina joins the optic nerve). The brain fills in this blank spot. This is a favorite for things like demonstrating optical illusions.

https://www.brainfacts.org/for-educators/for-the-classroom/2021/blind-spot-illusion-011921

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_AlreadyTaken_ t1_j46v8e4 wrote

Reply to comment by Rombolio in When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

Check out Oliver Sacks' writing on phantom limbs, it is very interesting. One guy had a prosthetic limb. It seems to get agile with a prosthetic you need this phantom limb effect. So this guy had to make his "appear" by slapping the leg stump and he could make it turn on. Some people even have severe pain in the phantom limb or it feels like the limb is contorted.

One interesting therapy for phantom limb problems is mirror therapy.

https://www.amputee-coalition.org/resources/mirror-therapy/

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_AlreadyTaken_ t1_j46ugpm wrote

Reply to comment by FineRevolution9264 in When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

This may help:

https://www.houstonmethodist.org/blog/articles/2021/feb/why-does-hitting-your-funny-bone-hurt-so-much/

>When you stub your toe, slam your finger in a door or smack your head, irritation and damage to your tissue triggers the surrounding nerves to coordinate nociceptive pain. These nerves inform your brain you're in pain — cue those sharp or throbbing sensations. Moral of the story: Stop doing the thing you're doing, it's causing damage.

>Nerve pain is a bit different. The pain is still coordinated by a nerve, but the irritation or damage is occurring directly to the nerve itself. In addition, the pain feels different — more electric, burning or stinging.

>In the case of hitting your funny bone, squashing your ulnar nerve into your medial epicondyle bone is irritating. And you feel this nerve pain in the areas where your ulnar nerve provides sensation, resulting in an unpleasant, shocking sensation shooting down your forearm and into your fingers.

So one is from nerve fiber sensory organs at the nerve endings. The other is affecting the nerve directly so it registers it along the entire region the nerve covers.

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_AlreadyTaken_ t1_j46u0oi wrote

Reply to comment by mckulty in When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

I read about phantom limbs and it seems that the brain expects noise from nerve fibers. It normally ignores this noise and considers it just a nerve fiber at rest. When the nerve is cut now there is no noise but there is no signal either. Without noise something must be happening but what? So the brain fills in the blank.

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_AlreadyTaken_ t1_j46tga3 wrote

Reply to When nerve damage occurs, where is the pain perceived? at the site of damage or at the end of the nerve? by menooby

I had an interesting experience with appendicitis. When I first felt it I didn't feel it in my lower right abdominal quadrant, I felt it right below my navel. At first I thought it was just something like constipation. Then by the next day it migrated to the LRQ.

I wondered why I had this experience and the answer was that the nerve for that region joins the spine at just below the navel. So at first I felt it at the spinal region then as the region around my appendix got more inflamed the pain sensation moved to that region.

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