Recent comments in /f/askscience

Grumblepanda t1_j4k1yk6 wrote

Reply to comment by DoomGoober in Why are skeletal muscle fibres bundled? by Repulsive_Cry_2200

There is a redundency factor in our bodies. If you had one main nerve firing one entire muscle that then gets damaged, you would lose entire control over that muscle and its function. If nerve pathways weren't shared, it would individualize group function (motor units). Think of it like roads in a city. The fascicles allow for micro stabilization within the muscles plane of movement, creating strength/integrity through changing force/velocity. (More data required) Developmentally we stress our bodies with different demand and stimuli, creating a reaction in how our muscles create shape. As we all have a similar bone and joint structure (compared to other animals) we have similar patterns to the base demands that our body develops in response to, so similar fascial presentations develop.

Please strike me down for any inaccuracies or incorrect generalizations. It sounds like you have some solid education behind you already.

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SurreptitiousSyrup t1_j4k005r wrote

Reply to comment by kkg_scorpio in Post exposure rabies shots protection? by [deleted]

Rabies virus infection, regardless of the variant or animal reservoir, is fatal in over 99% of cases, making it one of the world’s most deadly diseases. There is no treatment once signs or symptoms of the disease begin, and the disease is fatal in humans and animals within 1–2 weeks of symptom onset. Prompt administration of postexposure prophylaxis (PEP), consisting of rabies vaccine and immune globulin, immediately after exposure effectively prevents disease

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DoomGoober t1_j4jyi02 wrote

Reply to Why are skeletal muscle fibres bundled? by Repulsive_Cry_2200

My understanding was that each fascicle (muscle fiber bundle) has its own nerves and blood vessels.

Thus, the fascicle structure facilitates shared nerve control and energy/waste management of grouped muscle fiber cells.

Since the muscle fibers in each fascicle are trying to generate the same motion and generally all have the same function, it makes sense to bundle them together and link them all to the same nerves. And the same vessels (which facilitate the metabolic behavior of the muscle fibers.)

Edit: Sorry, I clearly wrote this badly. My writing implies that all the fibers fire at the same time with one set of nerves firing them all at once (I wish I could do that, as I could generate a lot more force when lifting weights! But then again, I might injure myself more easily.) Rather, while the muscle fibers share the same nerves bundles, I did not meant that they all fire at the same time or that the nerves don't branch off and act somewhat independently of each other even within the fascicle. Thanks for all of the corrections!

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IAmAPhysicsGuy t1_j4jydnx wrote

Reply to How do we know that we are in a certain place inside our galaxy? and how do we know how big it is just by looking at the cross section we are in? by friday_panda

If you were a passenger on a merry-go-round, would you be able to work out your position based on the movement or location of the other riders? Or when you look around and see other people on a different ride or a ferris wheel?

Your brain can calculate distance because of the parallax that you get from having two eyes. Or you can see that people look smaller when they are further away (assuming you are familiar with the average size of a person). You can also hear sounds change pitch as you move towards or away from them.

Imagine these same principles applying to different positions in orbit around the Sun throughout the year, type 1A supernovae, and red / blue shift of light, and you can begin to map images of stars and galaxies pretty well.

We can see that we are in a spiral shaped galaxy, and that we are not in a globular galaxy. Our spiral galaxy has arms with varying density, and we can also determine that we are in an area that is relatively less dense, meaning that we are between arms. We also can look towards the center of our galaxy and measure our distance from the middle

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Level9TraumaCenter t1_j4jwopv wrote

Reply to comment by Alwayssunnyinarizona in Post exposure rabies shots protection? by [deleted]

> Protection lasts a decade or more, but health departments will have different ideas about when post-exp is necessary, and tend to lean towards public safety.

Titer every two years, except for the two opposite ends of the scale: those in labs researching rabies (every six months), and "Animal care professionals and others who frequently handle terrestrial mammals in regions without terrestrial rabies," i.e.: cavers (no titer checks). I believe that latter group is supposed to get a booster every three years.

Should be good for several years, such as in your case.

Source: knuckle-dragging, mud-eating caver.

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