Questions tagged [human-physiology]
For questions on the biochemical, physical, and mechanical functioning of humans in good health including their organs and cells.
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How do we sneeze?
When a stimulus triggers the sneezing pathway, known as the trigenimal nerve network, how do the droplets from a sneeze get created within the nose? What affects the size of these droplets?
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Do spinal cord reflexes (such as the knee-jerk reflex) continue to function under general anaesthesia?
The knee-jerk reflex (patellar reflex) is an example of a stretch reflex (myotatic reflex). Stretch reflexes are monosynaptic reflexes happening in the spinal cord without involvement of the brain.
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If a human is stranded with beer but no water, should they drink it? [duplicate]
TL;DR: At what percent (if any) will alcohol dehydrate you more/faster than drinking nothing?
Let's contrive a situation for dramatic effect...
A human goes out on a boat for a nice sail in the sea. ...
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What determines excrement's caliber?
Often, pieces of feces have a clearly-defined shape and size — both length and width (that is, cross-sectional diameter, or caliber). But that width seems to vary quite a bit, even among pieces ...
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Drinking soda triggers tingling on a tiny spot on my upper back... but how? [closed]
The title pretty much says it all. Yes, I know it doesn't make sense. That's why I'm baffled.
For the past week or two, I've noticed that drinking soda seems to cause a tingling/stinging sensation ...
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Will a 0.2g/mL sugar concentration cause vomiting in humans? [closed]
This infographic claims that the sugar content in a can of Coca Cola would cause vomiting if not for the phosphoric acid.
In The First 10 minutes: 10 teaspoons of sugar hit your system. (...
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Do our belly buttons consist of scar tissue?
I read an interesting post on Facebook the other day saying that we all have a visible scar since birth - our belly button. This got me thinking (and research for me only found results regarding belly ...
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Peculiarity of chemo senses [closed]
We can easily recall our visual stimulus and auditory stimulus but why can't we recall chemical stimulus like smell and pain?
We can recall a song or picture but we can't exactly recall smell and ...
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Will the heart keep beating if it's separated from the body?
The heart is a vital organ in our body, as it drives blood circulation. I was wondering if a heart keeps beating if it is separated from the body? If yes, then why?
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Can light pollution cause cancer?
Impaired circadian rhythm is associated with cancer. Light pollution affects the circadian rhythm and the circadian rhythm affects the metabolism. But what is the (molecular) connection between ...
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What is the connection between sleep requirement and age?
By this question: Is the human biological clock genetically programmed or learnt? we discussed that the sleep requirement depends on the age of the individual.
- Figure 1. - Sleep requirements by age ...
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Can nociceptors die because of too much mechanical stress?
In martial art people hit their body (e.g., with small bean bags) to become more insensitive to pain. Can the sensory neurons die during this procedure? I think this is just an urban legend. Instead, ...
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Why some parts of the human body have immune privilege?
Why have the eye and CNS have immune privilege? Why does the body not develop tolerance against their tissue and instead risk their damage in case an accidental immune cell infiltration?
Wiki:
......
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Does creatine-phosphate (CP) supplementation regenerate NADH?
I have the following facts:
It is possible to convert ATP <-> creatine vice-versa. (ref - non scientific)
CP supplementation protects against metabolic syndrome. ref1 ref2
Fructose digestion ...
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Fats as energy source
As we know that the preferred source of energy for our body (source) are carbohydrates but heart muscle is an exception and need some explanation for this exception, that why the preferred source of ...
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Why is there smooth muscle in our bronchioles?
Having muscle tissue in our bronchioles that can constrict seems like a poor choice for tissue. Why would our airway want to ever close up? Wouldn't it be more beneficial for our bronchioles to just ...
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How is circadian rhythm of gastric acid secretion regulated?
Gastric acid secretion shows a circadian rhythm where acid production in the morning is minimal and it reaches a maximum towards the evening.
How is this process regulated?
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What would happen if we had a device that produced oxygen inside of our lungs? [closed]
Hypothetically speaking, suppose there is a device that produces a limitless supply of oxygen. The device is inhaled by a human and is resting inside the (a) lung.
What would hypothetically happen if ...
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How does ANF increase GFR?
ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
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Normal ECG/EKG Measurement?
I'm getting started using ECG using a 3 lead system by iWorx. I have place the leads on my two wrists and the ground on my ankle and have recorded some data into the provided LabScribe 3 software ...
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What creates the feeling of 'excess' blood pressure to an area of the body?
If I hang upside down, and feel blood rushing to my head, what structures are actually responsible for me "feeling" this excess flow of blood? Baroreceptors? Mechanoreceptors? Something else?
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Why does hair grow after trimming but remains at a constant length after a while?
Some hair especially body hair regrows after trimming but stops growing after a while. What is the mechanism behind control of hair growth and how is the length limit determined?
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awakening effects of light
I tried reading by light from a neighbouring room and felt sleepier than if my own lights were on.
Is there a formula for the intensity of light vs physiological preparation for sleep(calcium, ...
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Besides hemoglobin, what proteins are present in red blood cells?
I knew that mature red blood cells (RBCs) lacked nuclei, but I wasn't aware until just now that they also lacked ribosomes and mitochondria. Most cells in the human body all contain a common laundry ...
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When did our ancestors switch to a menstrual cycle instead of the estrous cycle?
The Wikipedia page on the Estrous cycle says:
Humans have menstrual cycles instead of estrous cycles. They shed their endometrium instead of reabsorbing it. Unlike animals with estrous cycles, ...
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Time for rigor mortis to set in [closed]
Rigor mortis sets in due to non-functional "ATP powered calcium pumps" as a result of which the calcium ions stream out & the muscles remain in a suspended animation state.
But, it's a frequent ...
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Can you build muscles from watching point of view videos of people weightlifting?
According to this, "new research has found that viewing other people exercise actually increases your heart rate and other physiological measures, just as if you were working out yourself".
This got ...
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How fast can a human run?
I'm a runner (cross country) and I'm always amazed at how fast Olympic sprinters are. There's a lot of hype about those in the 100-meter dash being the fastest in the world, and we're constantly ...
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How can ingesting a prion "infect" someone?
That's something that's been bugging me for a while...
Our gastrointestinal tract produces proteases that degrade proteins. Prions are proteins. Shouldn't they be broken by proteases?
Also, how can ...
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Do human anal glands have any function?
Anal glands in all kinds of animals play a range of diverse functions - providing fat for preening feathers or waterproofing fur, generating distinct scent, even repelling predators.
None of the ...
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Upon drinking water for the first time in a long time, why do I sweat?
If I don't drink water for a long period of time (e.g. 10 hours), as during fasting, and then I break the fast by drinking water, I start sweating. Why is this?
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Can food swallowed when a person is upside down reach the stomach?
If a person positions him/herself upside down and swallows food, will it reach the stomach against gravity? If so how?
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What chemicals can be detected in sweat?
This question came to mind after reading this article. The article speaks of inducing sweating to determine, by a roundabout fashion, the amount of salt therein. I'm no medic but I find myself ...
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In scuba diving, are nitrogen narcosis and high pressure nervous syndrome the same thing?
In training for scuba diving, they tell you that when you're bellow 100 ft or so you have to watch out for changes in mental state that resemble drunkenness. The cause of these mental disturbances is ...
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Are the intestinal microbiota substantially different within a diverticulum of the colon?
From the Wikipedia page for the vermiform appendix:
This proposal is based on a new understanding of how the immune system supports the growth of beneficial intestinal bacteria, in combination with ...
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How fast is the blood flow in various vessels?
How fast is the blood flow in different blood vessels, such as the aorta and capillaries?
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Why can hair grow without limit while eyebrow cannot?
I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit.
Why can hair grow without limit while eyebrow cannot?
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