Recent comments in /f/askscience

FiascoBarbie t1_j9hts1t wrote

Reply to comment by Lizardcase in Why are fevers cyclical? by Key-Marionberry-9854

Some pathogens produce pyrogens and some are produces by the immune system.

Pathogen load is not a major factor per se in many of these. There are always exceptions. Some viruses produce high fevers and some bacterial infections low or none, but as a general rule viruses don’t really activate the arm that produces high fevers they same way and extra cellular invaders. Also as a general rule, it doesnt follow the life cycle of the organism, Also with some notable exceptions, malaria being one of them.

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Unicorn_Colombo t1_j9htljs wrote

Reply to comment by CoastalPizza in Why can’t mules reproduce? by Imaginary_Camel4213

It should be noted that there are organisms where populations differ in their karyotype while still being compatible. This is quite common among rodents, where population of the same species can be easily identified with their karyotype, but still produce viable and fertile offspring.

So I don't know enough about this particular case to say where exactly is the problem, but just having a different number of chromosomes isn't such a barrier as people often make. Yet, it is still likely related because chromosomes represent organisational units. During meiosis, there are multiple steps where the material is divided. An unequal distribution might possibly be the cause, but again I don't know enough about this particular case and I would have to speculate.

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911derbread t1_j9htfdo wrote

Reply to comment by smellygooch18 in when a limb gets amputated, how do they stop the flow of blood? by EnchantedCatto

Generally, yes! There's really not a lot you can do to someone even as a layman that's really going to hurt them if you're trying to help, with maybe the exception of moving someone with a broken neck. It gets fuzzier for us doctors who might try to save someone with a procedure in the field that goes wrong, like a cricothyrotomy or c-section.

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concealed_cat t1_j9hqoeh wrote

Reply to comment by Bax_Cadarn in when a limb gets amputated, how do they stop the flow of blood? by EnchantedCatto

But if you're driving down a freeway, and then encounter a road block 3 miles past the last exit, then what do you do? The cars will just accumulate there with no obvious way out of there. If you cut the artery at a location without any branches, there will be some blood there that will just sit in place, won't it?

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Lets_Go_Why_Not t1_j9hoxtq wrote

Reply to comment by Marsdreamer in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

Sexual selection complicates attempts to explain certain evolutionary changes - sometimes, a trait just becomes more attractive to the other gender and, while that trait may represent an underlying superior fitness (beyond the obvious “can have more babies because I’m more fuckable than others”) it also may not. It’s possible that early humans just decided they weren’t down with hairy boning so much.

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mailbot100 t1_j9hobve wrote

Reply to comment by joedimer in when a limb gets amputated, how do they stop the flow of blood? by EnchantedCatto

My understanding is that arteries branch off to smaller and smaller branches, ultimately becoming capillaries where oxygen is exchanged, and then from those capillaries, they then flow to larger and larger veins, until the blood returns to the heart and lungs. This is, essentially, a closed-loop system.

In the case of an amputated artery, there must be some length of artery with no exit - it does not reach a capillary and I assume it does not just slowly seep blood into the surrounding tissue. The system at that specific point is no longer part of the loop. Is that correct?

So at the cul-de-sac end of the amputated artery, what happens to the blood stuck in that cul-de-sac?

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