Questions tagged [human-biology]

This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

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Does covid-19 has any particular host? Can it do effect other living things

Till now I'm not heard about any other beings affected by the covid-19 of its correct then explain your thoughts
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If cells require different types of food does that mean they are chemically different [closed]

If cells require different types of food does this mean they are chemically different
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Question about the anatomy of the human eye [closed]

Is there any part in the human eye that is responsible for keeping light out, or are all the parts of the eye involved in absorbing the light and allowing it in.
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What causes your 2 eyes to move in sync?

When you look left to right or up to down, youre 2 eyes move in perfect harmony. What nerve/system causes this coordination? I.e. could you tell me more about this system? Thanks
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Why do I have an urge to pee right when I open the fridge? [closed]

I have noticed that, very frequently, when I open the fridge door, I become overwhelmed by a sudden and urgent urge to pee that I didn't feel seconds ago. Is it normal ?
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Occurrence of non-functional, “spontaneous”, amino acid degradation?

Animals tend to have to consume proteins continuously. Amino acids are often degraded by synthesis of other compounds, including glucose and cellular respiration, catecholamines, etc, accounting for ...
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Can catecholamines degrade back into tyrosine, or, is synthesis irreversible? (in human body)

Catecholamines like dopamine, noradrenaline and adrenaline are broken down with enzymes that catalyze the reaction. Can they degrade back into tyrosine (a conditionally essential amino acid), or is ...
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Why is ammonia excreted? [duplicate]

Not counting CO2 from the lungs or water, humans excrete, by mass, as much ammonia as all other elements or substances, in the form of urea. Why is ammonia excreted? My best guess is that non-...
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What causes the overactivity of collagen production and expression in the cells of the nail bed/ nail matrix after some traumata?

What is the cellular mechanism of traumatic(sterile) onychodystrophy(hypertrophy)? I.e one hits his toenail and has it removed twice( once after the first trauma and then 3 years after the first ...
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1answer
32 views

Can far-UVC light be safely used as germicide? (help understanding a paper)

I've been trying to familiarize myself with the literature on far UVC light as a germicide. My question mostly pertains to figure 4 of this paper. The paper investigates the efficacy of 207 nm light ...
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15 views

Can humans eat a greater variety of things than other omnivores?

One thing that I've always noted is that humans seem able to eat just about anything that isn't toxic (and many things that are). Even when compared to other omnivores, I have the impression that ...
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Why do some children refuse to eat? Is this more prevalent in some cultures and eras, or universal for the human species?

Some children are specially problematic to accept normal food. This happens equally in all human cultures and all epochs (i.e. is it a biological condition), or is it related to culture and family ...
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Does a skin tag swell when it tied? [closed]

Does a skin tag swell when I tie it to remove? It has been a day and it is now swollen. And looks like it has transparent fluid in it
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1answer
68 views

Is it true that if a human lived long enough (up to 3-400 years), he/she would eventually develop cancer?

I have just studied DNA, but I am not so clear. So, I would like you to explain it more clearly. This is what I think when a human grow older and older, his or her DNA repair mechanism would be ...
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24 views

Are human nerve impulses digital or analog?

In other words, are nerve cells either firing or not firing, or do they have a continuous gradient of activation that influences other neurons' gradient of activation? This Forbes article says it's ...
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2answers
29 views

When does LH surge actually occur?

I’ve seen many textbooks saying that LH surge occurs in the Follicular phase while others say it occurs in the Ovulatory phase. I’ve tried googling this, only to end up knowing two things: 1) It ...
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Does the sperm with with best genes fertilize the egg?

Let's say a woman has four male sexual partners. If all four of them had sex with the woman on the same day and the sperms belonging to all four of them are inside the woman. Now is it true that one ...
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Does animal based food contain molecules that behave like dietary fiber for humans?

I have read that dietary fiber is beneficial to human health in many ways, for example that it can help to reduce risk of colorectal cancer. However, when I look at nutrition labels on food it seems ...
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1answer
35 views

Does the composition of a meal play a big, or small, role in food's thermogenic effect on the body?

Reading in: "Diet and Health: Implications for Reducing Chronic Disease Risk / Calories: Total Macronutrient Intake, Energy Expenditure, and Net Energy Stores" [NCBI Resources]: "The thermogenic ...
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2answers
100 views

How could the genocide of native Americans have happened? [closed]

According to work from Broden et al. (2015), the variation in the human immune system is largely driven by non-heritable influences. If there is little heritibility how can the genocide of native ...
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What fraction of embryos fail to be born? And why that high?

In the book Developmental Biology by Scott F. Gilbert and Michael J. Barresi, it says: Most human embryos die before being born. You survived. So how come is that true??? And what percentage of ...
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1answer
29 views

Are facial 'cleansing' products 'effective' on human skin, and if so, what is their mechanism of action? [closed]

All major supermarkets and beauty stores stock some form of facial cleansing products. They come in the form of scrubs, gels, and lotions which vary in application (from in shower, to apply daily ...
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Which test can be used to diagnose typhoid fever

The only thing I found was the widal test, which is no longer an acceptable clinical method. I can't find much information about this anywhere else other than the test needs to analyze samples of ...
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28 views

Salt water swish for dental health [duplicate]

I was wondering as to why warm water is told for salt water gargle and not cold water, does warm water has more therapeutic effect? Also does salt really work, excess salty water might kill bacteria ...
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60 views

What are the differences between internal organs between sub-saharan Africans and Northern Europeans

Lets take as examples a typical Norwegian and a typical Nigerian. In terms of human anatonomy the outer differences are more obvious e.g. (on average) White skin vs dark skin Pointy nose vs broad ...
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1answer
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Circulating Tumor Cell vs Circulating Tumor DNA

I'm a little confused about the wording of these two phrases and under which context the epithelial-mesenchymal transition occurs. For example: Is it the circulating tumor cell that releases the ...
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Is the “first pass effect” diminished more by some foods than others?

This effect and its considerations are fairly well known but it's never been clear to me whether it's a greater consideration with some types of food than others.
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Is there any disease in common between human and insects?

I am not asking about disease transferred by insects. I am wondering is there any disease that commonly make both human and insects sick?
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What's the function of vitelline circulation in human embryo?

Why do we need a vitelline circulation if we already develop a placenta to gather all the nutrients we need? Is it an evolutionary remain?
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How much blood do we have when the heart first starts to beat?

How much blood do we have when the heart beats for the first time? It should be between the third and fourth week of embryonic life.
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Reflex muscular activity in three months old fetus

At the end of the third month, reflex activity can be evoked in aborted fetuses, indicating muscular activity This quote is from Langman's Medical Embriology. Have I misunderstood it or it is ...
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How to start learning disease profiling?

I am student of Biological Sciences and interested to learn profiling in order to characterize the state of organisms (especially diseases). You know that there are different types of profiling like, ...
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1answer
62 views

Why are P and T waves curved and not straight (ECG)

The P and T wave are in shape of a curve while the QRS complex is in straight lines. What is the reason this is happening?
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1answer
65 views

Why is the body not able to “detect” imbalances and defects on its own?

We all know, our body is able to roughly localize pain sources or react to imbalances or defects: the stomach hurts because we may have eaten something spoiled, muscles hurts after exercising too ...
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1answer
49 views

How does an antisense RNA molecule restore protein function in CF patients?

I am researching a treatment for cystic fibrosis (CF) called Eluforsen and I am trying to understand the mechanism by which an RNA molecule can restore proper protein function. In many research ...
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What is Balbiani's vitelline body function?

I tried searching on Google Scholar but I found little to no information about this Balbiani's vitelline body. I don't even know why it is called vitelline...I've been taught that it can be seen ...
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How many different DNA of different species are there in the DNA of modern humans?

According to this DNA of extinct human species Aboriginal Australians, Pacific Islanders carry DNA of unknown human species, research analysis suggests and according to this Neanderthal ...
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Why does a stronger heart cause blood pressure go down

Intuitively, why does a stronger heart cause blood pressure to go down? The answers I've found from a cursory google search seem to indicate that it has to "work less hard" to pump the blood and that ...
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29 views

Why do vaccines sometimes induce a fever? [closed]

How does a vaccine cause an immune response such as fever? Why do only some people experience these reactions? Why might those reactions change upon subsequent doses of the same or similar vaccines?
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2answers
66 views

What's the purpose of segregating a virus from the blood and growing it in the lab?

I heard that the scientist in Australia found a way to segregate the 2019 NovCoronovirus from the blood. Does this mean they are one step closer to the cure? Why is virus segregation crucial in ...
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1answer
57 views

Pressure measurement blood flow

During blood pressure measurement, when the flow within the arteries of the arm is interrupted, how is blood flow redistributed to the rest of the circulatory system? Is it possible that more blood ...
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43 views

Do kids under a certain age not hear the warning beeps that smoke detectors make when they are running out of battery power?

I've always been very annoyed by those regular single beeps that smoke detectors start doing increasingly often as the batteries start to run out, to warn (and annoy) the user to replace the batteries....
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1answer
100 views

Is molecular oxygen (O₂) consumed in any process (in humans) other than acting as an electron acceptor for the ETC? [duplicate]

I know that molecular oxygen (O2) serves as the electron acceptor in Complex IV of the electron transport chain, which maintains the proton gradient that produces ATP for, as far as I know, every cell ...
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1answer
59 views

How are the images of both eyes combined to form one image?

When you see an object by one eye, ex.right eye, you see it from the right direction and the opposite if you see it by your left eye, but when you open both eyes, the image appears somehow centric in ...
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pH on skin penetration of salicylic acid

I have found that at lower pH, there is more free salicylic acid (due to pKa of roughly 3), which is neutral/uncharged and then can penetrate the skin's oils which are non-polar. At higher pH, more ...
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How does salicylic acid (2-hydroxybenzoic acid) break down desmosomal proteins to exfoliate skin?

I've been searching for an explanation to salicylic acid's property of being able to break down desmosomal proteins, such as desmogleins in order to disrupt the outer layer of skin. Can someone ...
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2answers
3k views

How can the organic mercury compound Thiomersal be not dangerously toxic?

My intuition tells me that organic mercury compounds are absolutely toxic. Unimaginably, fundamentally, extremely and uncompromisingly toxic. I know that is not true for all doses. Thiomersal is the ...
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108 views

Genetic variance for a behavioural trait among human populations

From this article from The Guardian: We instinctively assume that differences in behaviour that are in fact due to culture must be linked to – even caused by – characteristics of appearance. That ...
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1answer
78 views

Is it true that ethanol can have some positive effects?

I recently was reading this inforgrafics about excessive alcohol use. It is written: No one should begin drinking or drink more frequently based on potential health benefits I am surprised. Is ...
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3answers
350 views

Is sex a spectrum?

At the moment I'm especially interested in the question of whether biological sex is really a spectrum. Unfortunately I could not find any good answers on the Internet. Therefore I hope that some of ...

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