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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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Cause of numbness in feet [on hold]

Can excessive movement (except from walikng) of feet causes numbness in the feet? I repeatedly move my feet and feel numbness.
2
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0answers
36 views

Why does it take 24 hours for tendons to give feedback on whether the loads they received were excessive?

I heard in this interview of Jill Cook (tendon researcher) on https://youtu.be/GKkSp-TlofI?t=230: Tendons talk to you 24 hours later. So what happens if if I put load on a tendon today, it will ...
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0answers
20 views

Is it possible for a woman born without any eggs to have normal levels of estrogen?

If a woman has no eggs, she cannot menstruate and cannot get pregnant; but can her ovaries produce normal levels of estrogen?
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3answers
4k views

Can humans ever directly see a few photons at a time? Can a human see a single photon?

I am not asking the following question: Can humans ever see a photon in the same way we see a chair? My question is: Can a human retina respond to a single photon? If so, how does this happen and why ...
3
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1answer
73 views

Explain to a layperson how cigarettes smoke might cause cancer

I have a very intelligent friend who is a light smoker, and also a Biology layperson. I wondered whether understanding exactly how cigarettes smoke can cause cancer, might encourage him to smoke less ...
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8 views

Sensitivity of fever as an indicator of infectious disease

What is the sensitivity or likelihood ratio of fever as an indicator of an infectious disease? Where can I get the number from?
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0answers
43 views

What causes a tendinopathy to calcify?

I read in this 2012 research paper {1}: The aetiopathogenesis of CT [calcific tendinopathy] is still controversial, but seems to be the result of an active cell-mediated process and a localized ...
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0answers
12 views

For how long can the heart be in asystole and then restart itself?

The medication Adenosine is used for the treatment of some abnormal heart rhythms. However, according to Wikipedia, it can cause asystole for a few seconds: Because of the effects of adenosine on ...
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16 views

How important is getting enough glucose for maximal brain performance / cognition?

I know from many studies that have been done, that resting versus active use of the brain has relatively similar overall energy expenditure levels. On the other hand, however, we know that the brain ...
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0answers
13 views

Why are isometric contractions more analgesic than isotonic contractions for tendon pain?

According to a randomized clinical trial {1}, isometric contractions are more analgesic than isotonic contractions for tendon pain. The explanation they give is as follows: The antinociceptive ...
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0answers
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Would Cu1 or Cu2 oral supplementation be most likely to aid lysyl oxidase (LOX) production?

Forgive the basic question, I'm not a biochemist but am interested in understanding the below: LOX of course is key for interlinking collagen & elastin. At the same time, it is claimed that Cu1 ...
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1answer
51 views

How can space travel affect women’s fertility?

From Time: The reasoning behind the prerequisite, according to officials, is that spaceflight could potentially harm the women's fertility. How can space travel affect a woman’s fertility?
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CELL BIOLOGY AND GENETICS [closed]

How the criteria of size, charge, polarity and hydrophilicity/hydropathy determine whether a molecule will pass through the membrane. The amino acid requirements of proteins and how they are placed ...
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0answers
27 views

How do painkillers prevent shock?

I was reading about the Placebo effect and came across this little story: The roots of the placebo problem can be traced to a lie told by an Army nurse during World War II as Allied forces ...
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0answers
16 views

Does the Chorion Completely enclose the Amnion in Humans

When a human baby is born "en caul" (aka enclosed in the amniotic sac) the amnion detaches from the chorion and the baby comes out in the sac with the chorion still attached to the placenta. If the ...
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0answers
30 views

How does the strength of 3D printed tendons compare to original tendons?

There have been some attempts such as {1,2} to 3D-bioprint tendons. How does the strength of 3D-bioprinted tendons compare to original tendons? I am mostly interested in human tendons. References: {...
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Haemoglobinic acid

I’ve tried searching for the structure of haemoglobinic acid but it isn’t anywhere. I was trying to find out whether H+ ions bind onto the same site as carbon monoxide and oxygen on haemoglobin or not,...
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0answers
15 views

Does loss of dopaminergic neurons totally eliminate voluntary muscular control?

Breathing is a function that is not only autonomic, but can also be temporarily overridden and placed under voluntary control. In fact, you are now breathing manually. Now, suppose that someone has ...
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0answers
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Why does the ratio type III collagen:type I collagen increase after a tendon injury?

I read on {1}: Type III collagen has accumulated at the rupture site [of human Achilles tendon] probably due to microtraumas and the subsequent healing process. […] The increased content of type ...
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1answer
45 views

Why do bones only get bigger horizontally? [closed]

After growth plate closure, human bones only get thicker, never longer. Why is this? Is gravity the only reason? Is it obstruction from other bones? What constrains long bone vertical growth?
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1answer
69 views

Blood acidity and bones

By consuming acidic foods, could one cause their blood to become acidic and therefore cause an acid+base reaction between their blood and bone? I ask this because i recently discovered bone is a ...
3
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1answer
39 views

Why does cholesterol need to attach to proteins to travel through the blood?

I guess the deeper question is: what makes it possible for proteins like those part of HDL and LDL to move through the bloodstream?
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0answers
24 views

Does any tendon in the human body receive a high amount of blood supply?

I read on https://www.physiocomestoyou.co.uk/blog/all-you-need-to-know-about-tendons/ (mirror): [Tendons] do not have a large blood supply. Does any tendon in the human body receive a high amount ...
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2answers
3k views

Where can I find the list of all tendons in the human body?

https://www.healthcentral.com/article/aging-can-take-major-toll-on-womens-tendons (mirror) claims that: There are about 4,000 tendons throughout the body. This claim is echoed by a fair amount of ...
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0answers
48 views

Do stronger muscles lead to a decreased tendon load, and if so, why? [closed]

Does strengthening muscles help decrease the load that tendons have to sustain. If so, why?
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0answers
25 views

Why did nature decide to make plasma membrane of animal cell hydrophobic?

I am taking Introductory Human physiology course on Coursera. The teacher said and I quote " the membrane of the cell is a hydrophobic barrier that prevents any charged ions or molecules from moving ...
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2answers
167 views

Why are (some) human men sexually attracted to female breasts?

Many human men are sexually attracted to female breasts. Is there an evolutionary reason for this?
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0answers
44 views

Does eating hard food really cause wisdom teeth to erupt properly?

According to the article Bad molars? The origins of wisdom teeth, in our evolutionary history, people were eating harder food like nuts and had unimpacted wisdom teeth. Later, that article appears to ...
0
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2answers
34 views

Are there any non-pathogenic gram-positive bacteria in human gut?

I wish to know if there are any non-pathogenic (not even opportunistic pathogen) gram-positive bacteria in the human gut? Is there any reference that shows there exists a non-pathogenic gram-positive ...
39
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4answers
11k views

Can a person survive on blood in place of water?

This question: Can you get enough water by eating only fish? asks if a person could survive on fish alone. Can a person survive on fish and/ or blood alone of any species if stuck at sea or animal ...
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0answers
25 views

Could a reed mat delay human decomposition for over three years?

Based on a discussion over at Mi Yodeya. The relevant part here is the claim discussed there that if a body is buried wrapped in reed mats, it slows its decomposition by a factor of several years. Is ...
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0answers
58 views

Could an uncut umbilical cord benifit a baby?

How long and would there be any benefit like adding an IV line to the uncut umbilical cord after a baby is born? Can keeping the umbilical cord attached (and for how long) be beneficial or harmful ...
2
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0answers
43 views

Why can dogs hyperventilate without consequences like humans?

During the heat of summer, dogs usually breathes very fast, like 100 times per minute or more. If humans do so, we will experience an array of negative effects like dizziness, finger tingling or ...
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1answer
55 views

How does the human body extract energy from ethanol?

I was talking about alcohol and obesity with a colleague. I always thought the only cause of that is the sugar that is found in most alcoholic beverages. But my colleague pointed out that ethanol ...
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0answers
13 views

How are codocytes or target cells formed?

How are codocytes or target cells formed in conditions like Thalassemia? And why do they appear like a target(as in why is there a central red surrounded by pallor surrounded by red?)
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0answers
27 views

What is the significance of different types of papillae present on tongue?

Fungiform, Circumvallate, Filiform, Foliate Papillae are present on the surface of the tongue. They have a role in increasing surface area for taste buds that can be accommodated on the tongue. Each ...
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0answers
23 views

Are girls more often first born compared to boys in families with two children?

When there are two children, one girl and one boy, in a family are girls more often the oldest? If so what causes this?
2
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2answers
92 views

Why is HPV vaccines targeted for preteens?

Why is human papillomavirus products targeted to children before sexual activeness? Could all ages benefit from this vaccine even if they may have or have not contracted a form of HPV to prevent other ...
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1answer
39 views

is it possible for a son to inherit an allele on a Y chromosome?

Obviously, the only way for one to be male is to inherit the Y chromosome, but are there alleles on the y chromosomes? Or is it just automatically the recessive trait without an allele.
4
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1answer
67 views

Is returning cholesterol to the liver really performed by HDL?

Various answers in biology SE, including two quite upvoted ones (1, 2) claim that (in humans) returning cholesterol to the liver is done by HDL. If I understand correctly, Wikipedia's Reverse ...
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0answers
54 views

Can one assess muscle strength through imaging (e.g., MRI)? If so, though which type of imaging and how accurate is it?

Can one assess muscle strength through imaging (e.g., MRI)? If so, though which type of imaging and how accurate is it? On How does muscle size relate to strength?, I read this answer from Moses (...
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1answer
65 views

Is drinking your urine an effective way to stay hydrated in a hostile environment?

There are quite a few stories about people trapped or otherwise incapacitated resorting to drinking their own urine in an attempt to stave off dehydration, ignoring the long term consequences, my ...
0
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1answer
45 views

Understanding genetic similarity in humans [duplicate]

I was reading "Blueprint" by Robert Plomin (online preview on webpage) and got stuck when I got to these two sentences in the prologue: "We are the same as every other human being for more than 99 ...
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1answer
22 views

Is “muscular attachment” synonymous to tendon? (when talking about the insertion of glutei medius and minimus to greater trochanter of the femur)

I have read the following two terms in an MRI report (both points refer to the insertion of gluteus medius/minimus to greater trochanter of the femur): mild degeneration of the muscular attachment ...
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2answers
2k views

Is NMDA produced in the body?

On the wiki page for NMDA it says that NMDA is a synthetic substance that mimics glutamate. So why does the body not use glutamate instead of NMDA? Also how is it possible that our body can produce ...
2
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2answers
47 views

Is it impossible to increase skeletal bone mass, as opposed to just bone density? [closed]

I've heard exercise and resistance/strength training increases the density, but doesn't increase mass. So basically, experimentally or theoretically possible at least, can modern science do this/is it ...
2
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0answers
21 views

Could certain drugs enable one to consistently eat above TDEE or BMR without fat gains?

I heard anabolic steroids and stuff like DNP and ephedrine and etc. can somewhat enable one to eat more and get away with it without much or any fat gain, despite eating more than the body would ...
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0answers
42 views

Does the molecular composition of human body change after a period of time?

I was discussing change in human biology over time and my two in-laws charged in saying, "we're molecularly different after x". I didn't pay attention to what time period they exactly mentioned (hence ...
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0answers
21 views

Does the human body absorb any of the humidity in the environment when dehydrated?

I was walking in the rain and feeling thirsty, and I wondered if when the human body is dehydrated it does absorb any of the humidity in the environment by itself.
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1answer
130 views

How much does biomagnification affect human beings?

It is known that the effect of biological magnification increases with higher trophic levels. Since, we are at the top of the food chain, how much are we affected by it? Is there any proof of humans ...