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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1answer
239 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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Is orgasm necessary for long-term male sexual health? [closed]

Though many sources tout potential health benefits of orgasms (googling the thread title will confirm this,) I don't see any that address the question of actual necessity. Do postpubescent males need ...
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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
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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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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
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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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Is it true that after an illness a human organism “refreshes” and may become physically stronger for some period?

I’m doing athletics and I heard my coach say once that after a light illness a sportsman may peak in productivity, because the body refreshes or something like that. Is it true? Is there a scientific ...
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1answer
53 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
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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
115 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
99 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
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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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58 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
44 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
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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
44 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
62 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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0answers
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
43 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
81 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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0answers
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Why does (insulin induced) hypoglycemia stimulate ADH secretion?

Intuitively, I understand that ADH (Anti Diuretic Hormone) is responsible for maintaining osmolarity, and increased serum osmolarity is a stimulatory factor for its release-- ADH increases water ...
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38 views

Does Vasa deferens produce any secretion in the Human Body?

I got this doubt while attempting the following question: ...
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1answer
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colocalization by IFA?

I have done IFA (immunofluorescence assay) previously but i targeted only one protein or i tagged my endogenous protein with GFP/RFP then i performed IFA. I want to do the IFA in parental cell line (...
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1answer
59 views

What is the best method to check for differential gene expression in large dataset? I want to identify aging differentially expressed genes

My data is RNAseq data and I want to know which all genes (which I am looking for) are differentially expressed with age. I have tried the Kruskal-Wallis test and fold change methods. Do you have any ...
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45 views

Exclusion and inclusion criteria for healthy controls in colorectal cancer study

I'm working on colorectal cancer, and I'm facing a problem in the sampling step, I can't figure out how to choose healthy subjects. In the literature, I've found many criteria that are different and ...
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0answers
31 views

What are evolutionary reasons for humans' limited regeneration abilities? [duplicate]

As far as I understand (I am not a biologist), a ability of a species arises during the evolution if: It increases reproduction chances It is not too energy expensive It is physically possible At ...
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1answer
85 views

How much light can pass through the human eyelid?

My sister tells me that at night when the lights in the room are off that she can see the ambient outdoor light from neighboring buildigns and streetlights through her eyelids (i.e., when her eyes are ...
3
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1answer
128 views

How many senses do humans have?

I recall learning that humans have 5 senses, but that may have been an over-simplification to focus on the most notable ones, or simply that no others were known about at the time. Wikipedia says: ...
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1answer
67 views

How do you determine "in which direction" DNA is shared between groups of people

In popular DNA ancestry tests you can read lines like "you have 2% neanderthal dna" or "you have 20% italian". How can you distinguish between a person having 20% italian vs ...
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1answer
75 views

Why is only the donor's antigen seen during a blood transfusion?

I am a high school student and I am a little confused that why only donor's antigen matters during blood transfusion? for e.g if the donor's blood is O- so it means that it will antibodies against all ...
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1answer
58 views

Why is the chordate nerve cord described as hollow when it appears to be solid?

My textbook says arthropods have a double, ventral, solid nerve cord. And chordates have a single, dorsal, hollow nerve cord. What is hollow exactly in a cord that looks like this?
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If excess sodium is bad for humans, why don't our bodies just remove it?

This is one of those questions where I realized two everyday facts don't connect for me. Excessive sodium in the diet is supposed to be bad for us. But surely our bodies have mechanisms for getting ...
3
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1answer
63 views

Can any gas other than nitrogen cause decompression sickness (the bends)?

I know that our bodies use most of the oxygen we breathe in during a dive but, wouldn't our tissues, under pressure, absorb more oxygen than we need? For instance, in normal circumstances, we don't ...
4
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1answer
55 views

How is the renal osmotic gradient maintained even though the blood osmolarity changes?

I am a high school student and I am a little confused in 2 things related to our urinary system: We know in our kidneys a countercurrent mechanism exists due to which there is a steep gradient of ...
3
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1answer
149 views

Do people need nitrogen from air for health?

Can people breath totally nitrogen-free atmosphere for a long time? I know, nitrogen is essential for life, and in big quantities, but maybe people can take it entirely from food, from proteins, etc?
3
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1answer
98 views

Is covid vaccine helpful for a covid patient?

I am not a biology student and this question came in my mind out of nowhere. I read somewhere that the vaccines contain some denatured or almost dead corona viruses and when these are injected in our ...
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1answer
147 views

What exactly makes red meat (probably) unhealthy?

It seems generally agreed that (even fresh, unprocessed) red meat is at least somewhat bad for human health. But why exactly is this the case? It's difficult to find any attempt at an explanation, ...
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1answer
61 views

If a person touched an electric eel, would they sustain electrical burns as if they touched a high tension power line?

I've been wondering this, if an eel was continuously shocking someone, would they sustain electrical burns as if they touched a high tension power line due to the high voltage and amps?
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22 views

Effects of a constant magnetic field on the human body (especially blood circulation and ion channels)? [duplicate]

Recently, while searching for the safety of MRI, I read in several places that hemoglobin and iron in the blood are not significantly affected by magnetic fields, so MRI is safe. However, since the ...
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1answer
42 views

Do phagocytes need antibodies to be able to engulf pathogens (to function)?

I recently saw a question about monoclonal antibodies, that are specific to a certain virus, being split (into their constant and variable regions via an enzyme), and the question asked whether some ...
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2answers
1k views

Why is haemophilia unviable in later stages of life?

A sentence in my textbook is: The possibility of female being haemophilic is extremely rare because mother of such a female has to be at least carrier and the father should be haemophilic (unviable ...
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0answers
15 views

Quantitative comparison of rate of energy output when burning carbs compared to fat

I'm studying scientific models of endurance exercise such as the one in a paper by Rapoport (see references below, popularization here). If I'm understanding properly, fat burning is in some sense ...
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1answer
56 views

I hit an area of my elbow and had a burning sensation throughout my hand

I happened to bump the side of my right-hand elbow on a corner and suddenly felt a burning sensation on the right side of the hand elbow-up. Any theories that could describe what I recite?
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1answer
71 views

If massive animals live longer, why do humans with gigantism die younger?

What I mean is humans suffering from gigantism (type 1 neurofibromatosis, Marfan syndrome, X-linked dominant acro-gigantism, et cetera) rarely live more than 5 decades (50 years). The same can be said ...
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0answers
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Is protein intake required for the formation of new myosatellite cells?

Hypertrophy of muscle fibers requires an adequate (significant, really) intake of protein, but what about just forming new myosatellite cells as a response to a stress applied to the muscle? Does that ...
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1answer
59 views

Check simple human fetus answers

Based on this image and questions, could someone please check my answers? Question 1: At which one of the following points will the blood passing the point be more oxygenated after birth than before ...
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0answers
46 views

Are there epigenetic effects in the regulation of human height?

Development of human average height Human average height has fluctuated significantly throughout history. For instance, in the last 100 years or so, it has increased sharply by about 10cm. OWID (Our ...
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1answer
74 views

The Relationship between Copper and Alzheimer's Disease

I've been reading up about the research concerning the etiological factors behind Alzheimer's and I came across two papers - "Studies on Copper induced stability changes in DNA fragment (GCA ATC ...
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1answer
45 views

How many cells need to be damaged before a human can feel it as pain?

I'm guessing the answer to this question is rather large. Skin cells die all the time, it seems, and that never registers as painful. But suppose you rupture or otherwise destroy a group of cells, say ...

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