Wikipedia:Reference desk/Archives/Science/2015 November 17

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

November 17

Neuroscience: Is my "Sympathetic fight response" axis accurate?

Peripheral sensory cell > Preganglionic cell > Dorsal root ganglia cell in the Sympathetic chain > Ventral root ganglia cell in the sympathetic chain > Post-ganglionic cell that activates an organ such as the pancreas (or a muscle).

Was I accurate? I ask this after feeling that some books\people tend to confuse the details of this axis... :|

Thanks, Ben-Yeudith (talk) 03:30, 17 November 2015 (UTC)

That pathway might come into play, but it wouldn't generally be called a "fight" response unless brain circuitry is involved. See fight-or-flight response, and for further information sympathetic nervous system and norepinephrine. Looie496 (talk) 14:31, 17 November 2015 (UTC)

Dehydration and swelling

Why does dehydration cause swelling of various body parts? 2A02:C7D:B8FF:7E00:A9FD:A524:5C8A:311F (talk) 09:06, 17 November 2015 (UTC)

I don't see anything in Dehydration that talks about swelling. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:14, 17 November 2015 (UTC)

Perhaps the questioner is thinking of the abdominal swelling seen in severely malnourished children. See here for some explanations. AndrewWTaylor (talk) 11:37, 17 November 2015 (UTC)

Kwashiorkor isn't a dehydration symptom (it's the product of a specific kind of malnutrition), but might be what the OP is thinking of. See also Swelling (medical) and edema. 99.235.223.170 (talk) 01:43, 19 November 2015 (UTC)

Gorse brush prickles cause a rash but what is the active agent?

What about gorse bush prickles causes an inflammatory response? Getting prickled by gorse bushes causes an inflammatory response so the pricks appear as red spots which persist a couple of days following exposure. A friend said it was "phenolic compounds" but I can't find anything about it online. --129.215.47.59 (talk) 11:34, 17 November 2015 (UTC)

This [1] says that formic acid is present. SemanticMantis (talk) 15:20, 17 November 2015 (UTC)

Thanks but I think you misread the source. The formic acid is in nettles. --92.6.114.248 (talk) 20:54, 17 November 2015 (UTC)

The source provided says (quoting directly)

• 78. Ulex europaeus
• Common names:- Gorse
• Part used:- flowers
• Effects:- some astringent action, flea repellant
• Chemicals present:- tannins. No further data available at the present time.

Relevant here is the statement that it has astringent properties which are likely caused by tannins. --Jayron32 21:20, 17 November 2015 (UTC)

@92.6.114.248: related event, this was caused by an 'inflammatory response' other then the gorse itself:

• "Dog walker killed by a scratch from a gorse bush" Daily Mail, May 2006.

The 74-year-old woman actually "... died from the 'flesh-eating bug' necrotising fasciitis" caused by "group A streptococcal infection". 220 of ^Borg 22:47, 18 November 2015 (UTC)

Yes, the Daily Mail headline suffers from the post hoc ergo propter hoc fallacy: She was killed after the scratch, by something unrelated to the nature of the cause of the scratch. --Jayron32 23:42, 18 November 2015 (UTC)

Like "We all eat food, and drink water and we all die", therefore: "Don't eat, or drink water, and you will never die"? No, I think that's Correlation does not imply causation. - 220 of ^Borg 06:02, 19 November 2015 (UTC)