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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2answers
51 views

Are there any biometrics that can measure tiredness (sleepiness)?

Are there any biometrics that can estimate how tired someone is? I specifically refer to tiredness in the sense of sleepiness (as opposed to physical tiredness that might happen after a workout, for ...
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0answers
29 views

Cancer Biomarkers [closed]

I have 3 questions: 1: Do You know Cancer Biomarkers, that are located in ISF (Dermal interstitial fluid)? 2: What biomarkers of other diseases can be found in Dermal ISF? 3: Can You give me some ...
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What is the true response of human photoreceptors to different wavelengths? Why is there so much disagreement in the literature?

I can find several qualitatively different diagrams of the responsiveness of human cones and rods to different wavelengths of light. A page referencing Bowmaker and Dartnall, 1980 has the following ...
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27 views

Is nose structure determined primarily by heredity or environmental and physical conditions of the body? [closed]

Nose structure is determined by the shape of the nasal bone and the cartilage in nasal cavity. My question is , in teen years, is nasal structure determined primarily by heredity or environmental and ...
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41 views

Does cancer really remain undetected about 80% of its life?

I was reading Atomic Habits by James Clear, who mentioned this and decided to google it. The only mention of this at least in the first search page was from this source from February, 2012. Is there ...
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cAMP actions on body [closed]

I know that several processes are mediated by cAMP. I searched for a chart or handbook containing all processes increased or decreased by cAMP. I have a good collection about such topics but the ...
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0answers
60 views

Sexual devolpment and sexual organs in humans

In an anatomy book from a friend studying medicine (Netter's book), I looked at some elements of sexual development in embryos. From a developmental stance, we can draw some analogous organs that ...
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0answers
98 views

Why are humans brown over grey?

Humans tend to have a brown skin tone, with very few people having grey skin. This seems strange compared to the other apes, where grey skin is exceedingly common. I have not managed to find any ...
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2answers
94 views

What is the connection between LDL, liver, and saturated fat?

I've been trying to learn about cholesterol, lipoproteins, and fats, but unfortunately, there is an ocean of confusing information on the internet. I don't have any solid background in biology, so ...
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0answers
136 views

What is the average density of mucosal gel in the mammalian stomach?

What is the average density of mucosal gel in the mammalian stomach (for example, humans, pigs and rats)? Units of measurement: grams per cubic centimeter or milligrams per cubic centimeter. Search ...
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1answer
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What specific interaction between methylphenidate and quetiapine causes toxicity concerns?

A number of reputable sources on drug interactions posit a potential interaction between methylphenidate and quetiapine, described on Medscape as follows: quetiapine increases toxicity of ...
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98 views

If x amount of a chemical starts to become harmful for a mice, then will 3000x amount of it start to get harmful for a human (3000 times heavier)? [duplicate]

My reasoning is simply that since human beings are 3000 times heavier than mice, the safety threshold for exposure to a chemical should be approximately 3000 times higher for human beings as compared ...
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Why are scientists saying that the Omicron COVID-19 variant is a reason to get a booster?

I was watching Vox’s video, Big questions about the Covid booster shot, answered, which references the New York Times article Omicron Prompts Swift Reconsideration of Boosters Among Scientists. In ...
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1answer
243 views

What are the Genes/Enzymes responsible for the supposedly stark between-individual differences in lethargy after eating starches?

Andrew Huberman claims in one if his podcasts episodes that: [...] because starches cause the release of serotonin in the brain and lend themselves to a state of sleepiness. Now, I should mention ...
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What is the upper limit for 'active' vaccinations

As far as I know the effect of vaccines is caused mainly by creating Memory Cells specific to a single pathogen. As there is obviously a lower limit of memory cells needed for immunity ( at least one),...
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The village of Twins — Mystery behind and Scope

With the presence of more than 200 twins, Kodinhi , a village situated in Malappuram District in Kerala , India , is popularly known as the "Village of Twins".This phenomenon of large ...
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1answer
79 views

Is lysozyme present in the lysosome? [closed]

Is lysozyme present in the lysosome? I cannot find anything about this in the literature.
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31 views

Bladder size based on child height/weight [closed]

My son is 10 years old, but weighs 24kg, which is quite little for his age. Is it correct to estimate his bladder volume based on a formula using age? This seems to be a generally accepted way, for ...
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1answer
85 views

Why cant humans digest dietary fiber when we can digest starch?

So, I can see that there's a couple of questions touching on this subject already, but none of them answer the aspect that I'm curious about: Dietary fiber is a polymer composed of multiple starch ...
28
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1answer
7k views

Do we know all the possible human hair colors?

I occasionally see people with blue hair and I always assume it is dyed. I wonder how justified is that assumption. Have biologists determined all the possible human hair colors? Or is it possible ...
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0answers
22 views

At what cold temperature at thermoreceptors human feel pain (e.g. in fingers)?

I've tried web search but have not found that specific answer. As far as I know at least some people feel pain (e.g. in fingers) when exposed to cold for prolonged amounts of time. E.g. here ...
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1answer
529 views

How many drinks were consumed by each test subject in this study?

I was reading this study and came across the following line: ...subjects consumed either 500 mL of whey protein (25 g; PRO), alcohol (1.5 g·kg body mass⁻¹), 12±2 standard drinks) co-ingested with ...
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0answers
24 views

Which of dB or dBA are more useful for predicting damage to hearing?

With no information about noise other than its loudness measured in decibels or in A-weighted decibels, which can be used to more accurately predict how much hearing damage may be caused? Even though ...
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1answer
101 views

How is a thickening of grey matter possible?

There are plenty of studies that document grey matter thickening in certain brain areas as a result of meditation or exercise. However, it's often said that the extent of neurogenesis outside of the ...
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0answers
64 views

Can the effect of an allele on height be context-dependent?

Some data is available on the effect alleles have on height. For example Common DNA Variants Accurately Rank an Individual of Extreme Height However after browsing the literature I was not able to ...
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1answer
178 views

Why do humans share over 99% of their genomes?

From Wikipedia The haploid human genome (23 chromosomes) is about 3 billion base pairs long and contains around 30,000 genes.[33] Since every base pair can be coded by 2 bits, this is about 750 ...
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3answers
122 views

Is it possible to fuse DNA from two sperms and can a baby be born from that? [closed]

If this is possible, then isn't there going to be a chance to have a YY child?
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2answers
84 views

What evolutionary advantage do separate teeth have compared to a single piece of bone? [duplicate]

Humans and many animals have multiple teeth consisting of separate pieces of bone embedded in the jaw. For humans, this arrangement has some disadvantages: teeth are quite fragile when impacted and ...
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1answer
40 views

Why does the body lose enzymes over time?

I recently started my GCSE Biology course where I spend the next two years learning and preparing for my GCSE. One of the questions I have is that I was told that enzymes are recycled every time they ...
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1answer
36 views

Why ions created in our body doesn't give any sensation of electric shock?

We know almost every cell in human body uses ions specially nerve cells , still why we are not getting shocked by those ions ?
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22 views

What is the difference in the function of tractus rubrospinalis and tractus corticospinalis?

What is the difference in the function of tractus corticospinalis and tractus rubrospinalis? I know, that they begin in different parts of the brain, but from what have I read on the internet*, I can'...
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1answer
265 views

Are there any phenotypically visible examples of gene linkage in humans?

Are there any examples of two "visible" or "obvious" phenotypic traits in humans that are a priori unrelated, but which tend to be inherited together (i.e. their inheritance ...
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0answers
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What determines if a compound is primarily uptaken by the lymphatic extensions rather than the portal vein blood supply in villi of the intestine?

I am currently studying the intestinal absorption/transport systems, but confused about one part specifically. There are hydrophilic and lipophilic compounds (to varying degrees), and they get ...
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2answers
4k views

How is heavy water detrimental to the human body?

Heavy water (D2O) is known to be lethal to humans and other life in large quantities. All I've been able to find on the toxicity is that it's similar to chemotherapy chemistry. I'd like to know ...
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0answers
23 views

Are there any congenital anomalies that cause a lack of epicanthic folds in a child who would normally have them?

Wikipedia lists several medical conditions associated with epicanthic folds. Mount Sinai says that epicanthic folds in a baby who would not be expected to have them is a diagnostic tool that indicates ...
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1answer
52 views

What are the roles of ATP and ADP in muscle contraction?

I've always known that the hydrolysis of ATP generates ADP, P, and energy, so I'd assume that if energy is necessary in a given process, ATP hydrolysis should occur (or another exothermic process). ...
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1answer
75 views

Why do babies urinate when they hear "SHHH.." sound? [closed]

I have noticed it many times in the region where I live. I don't know if its common World wide. But I think someone else would have noticed it. So why does this happen ?
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1answer
41 views

Why is BRCA-1 mutation a dominant mutation?

BRCA-1 gene is a tumor suppressor gene and undergoes a loss of function mutation to become cancer inducing. Why is it that only one allele needs to be mutated because loss of function mutations are ...
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0answers
37 views

How does medicine work? [closed]

Take aromatase inhibitors for example. In order for a molecule to stop the enzyme aromatase from converting androgens into estrogens, it must meet 6 criteria: Not get broken down by the acidity or ...
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1answer
126 views

Is there any chance that the COVID-19 virus could become more deadly by it interacting with the HIV virus?

I would like to know if there is any chance that the COVID-19 virus, or one of its variants, could become more deadly by interacting with the HIV virus. Let's say for example, that a person who has ...
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1answer
108 views

Why does inert gas asphyxiation trigger unconsciousness almost immediately?

According to an official safety bulletin from the U.S. Chemical Safety and Hazard Investigation Board: "Breathing an oxygen deficient atmosphere can have serious and immediate effects, including ...
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1answer
121 views

Should fat calories' numerical values be increased to better reflect the new scientific findings?

According to a study discussed on this website, people lose more weight on a calorie restricted fat reduced diet than on a similar calorie restricted carb reduced diet. Is this study a fair dinkum, ...
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80 views

Why does the friction of the sexual organs cause ejaculation?

What is the physiological mechanism?What kind of physiological phenomenon can friction cause? Why does friction produce orgasm and generate electric current in the body?
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1answer
54 views

Why do colors clash in your brain?

Wen pairing two or more colors together, some "clash" or cause a effect visually where the two colors meet. To me it appears to be a black line between the colors or shading when in fact ...
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0answers
24 views

Why/How can Hydrophobic things pass the lipid bilayer? [duplicate]

I’m just looking for a simple answer for this question. I’m in Bio 10, and don’t know the in depth stuff. So the lipid bilayer is hydrophilic and the ends, but hydrophobic in the middle; so how can ...
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0answers
82 views

Eye vision for distant large objects versus small close objects

We often hear that looking at distant objects after staring at screens is good for the eyes to prevent strain. But from the perspective of eye muscles, what is the difference between small font that ...
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1answer
63 views

Why can't I swallow the entire (liquid) contents of my mouth at once?

I've tested this out using water - I manage to fit a certain amount of water in my mouth, but if I try to gulp it all at once, I fail: I feel like spitting the water out (gag reflex?) There's a ...
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28 views

Why are symptoms like headache and coma common in patients of metabolic acidosis?

Metabolic acidosis is a systemic electrolyte disorder in humans. Headache is a common symptom of metabolic acidosis. Is the headache due to excess amount of acid and coma when the brain becomes too ...
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1answer
51 views

What are proliferating, but "normal" (non-cancer, non stem) cells of the human (mouse)?

What are proliferating, but "normal" (not cancer, not stem, not differentiating) cells of the human (mouse) ? Typically after differentiation process finished the cells stop proliferation. ...
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2answers
83 views

Is it possible for someone to be of no race? [duplicate]

I apologize if this is not the right forum to ask this question, but I don't know of any better forum to ask it. It is certainly possible for someone to have no religion, but is it possible to be of ...

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