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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6
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1answer
86 views

Why are pilots under the illusion of gaining altitude without doing so?

We had a lecture about the balancing systems of the body (mainly the otolith organ / semilunar canals) in which a case was described where a pilot crashed into a ship. He was supposed to keep his ...
4
votes
1answer
534 views

When is the lactase in lactose-free milk active?

Recently we have started suspecting that one of our children has hypolactasia (lactose intolerance), and so accordingly I have had my first exposure to lactose-free dairy- and dairy-like products. In ...
2
votes
1answer
277 views

How does the brain instinctively know the math behind Newtonian Physics?

A 10 year old child does not have the intellectual power to accurately calculate the energy required to throw a ball an arbitrary distance. Yet they are able to accurately throw a ball at a ...
6
votes
1answer
533 views

Is there a biological basis to physical attraction?

Is there something encoded within us that makes us attracted to, e.g., someone taller or shorter with blonde or brunette hair with green or blue eyes? Or, is this phenomenon completely based on ...
6
votes
1answer
99 views

What is the biological mechanism linking temperature and probability to be infected with a virus?

It is common knowledge that when you're cold you could get a cold. What is the mechanism linking temperature and viral infection?
7
votes
3answers
444 views

Is there any biological reason that professional swimming is dominated by white people?

I suppose that the question should be turned around to "Why is it extremely rare to see black people competing in professional swimming?" because it is the absence of this phenotype while watching the ...
3
votes
2answers
126 views

What is the biological basis for a human's ability to think clearly and be aware while “fighting/competing”?

I'm interested in learning more about the biological systems or hormones or parts of the brain that affect short term (<15 minutes) ability to concentrate attention on the task and be aware of the ...
3
votes
0answers
86 views

What controls the feeling of discomfort/comfort before and after sleep?

I'm interested in which biological systems or hormones are involved in the following phenomenon: Before sleep it may be difficult to find a comfortable position, and muscular aches and pains are more ...
6
votes
1answer
58 views

On the effect of polluted air on health. Is it more gradual, or more immediate?

I've heard time and again that living in São Paulo (a large city in Brasil) takes 1.5 years from your life expectancy. The allegation is that this happens because of air pollution. I am just ...
4
votes
1answer
101 views

Is there a correlation between incidence of type 1 diabetes and vitiligo?

Does the data indicate that if you have one, the probability of you having the other is higher than that of someone who doesn't have the one?
1
vote
1answer
312 views

Is sperm contagious?

A person may have a cold or any other disease that is an airborne-infection. Is their sperm also contagious? Should the person take any precautions?
8
votes
1answer
424 views

A timeline of the odds for survival for fertilized eggs and fetuses

I'm looking for data to build a timeline of the odds for survival of a fertilized egg, i.e., What are the odds it'll last a week? What are the odds it'll last a month? 2 months? (and so on ...
8
votes
3answers
953 views

If body temperature is 37°C (98.6°F), why are most people more comfortable at around 21°C (70°F)?

It may be different for other people, but for me, anything above 32°C (90°F) is very uncomfortable, and my body is inclined to seek cooler temperatures. But I would think that at 32°C, the body would ...
2
votes
0answers
62 views

Are there any situations in which phenylephrine is preferred to pseudoephedrine?

In the mid 2000s in the US, due to issues of drug enforcement, pseudoephedrine containing medications were brought behind the pharmacy counter and in most cases require ID, and phenylephrine was ...
10
votes
1answer
146 views

Does stress physically age our body?

Going by the assumption that stress eventually triggers a flight/fight response, and the subsequent realization that flight/fight puts the body in a system of readiness to use it's available resources ...
4
votes
0answers
164 views

How do the pharmacodynamics of the NSAIDs differ and are there “resistant” COX phenotypes?

I know that the non-steroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, naproxen) affect the enzymes cyclooxygenase (types I and II). Is there any difference in the degree to which these ...
3
votes
1answer
81 views

Predictable microchimerism

I read in New Scientist recently that microchimerism occurs between previously born siblings and grandparents, not just the mother. Do we know which parts of the genome are likely to be transferred? ...
2
votes
1answer
1k views

What is the “lifecycle” of an average eschar and what types of cells are involved in each stage?

(after some deliberation in the comments, I've decided to make the question more general) An eschar or "dry scab" often forms at a site of injury over a large cut or sore. It seems as though the ...
4
votes
1answer
73 views

What are possible health risks to women having large numbers of children?

What is the possible health issue the women would face in this record? The record for most children born to a single couple belongs to the first wife of Feodor Vassilyev of Russia. In 27 ...
13
votes
1answer
704 views

Are human bodies programmed to die?

Following from this question: What is the evolutionary advantage of death?: Is there any evidence that human bodies have systemic self-destruction built into their developmental program? I'm not ...
6
votes
2answers
417 views

What is the relationship between migraines and histamine?

A family member suffers from migraines so I have been reading a little around the subject. There seem to be any number of "triggers", but I have seen mention several times of the role of histamine ...
5
votes
1answer
432 views

Total amount of CO2 / Oxygen in Bloodstream in Humans

How much carbon dioxide and oxygen from/for respiration are in the bloodstream at any one time? (mass per litre of blood or similar) And would there be much more aside from the blood in tissue, e.g. ...
3
votes
1answer
3k views

Why do we sweat after drinking water and running?

Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?
11
votes
1answer
820 views

Why does hair turn grey or white, and why does it happen later for some?

The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some ...
1
vote
0answers
32 views

Can progerin formation be triggered explicitly?

Corollary to my question - Could inhibition of progerin formation slow the rate at which a body ages? Is it possible to activate/trigger progerin formation explicitly? Say, by some hormonal/chemical ...
1
vote
2answers
365 views

Shouldn't evolution have taken care of baldness already?

It is my understanding that the hair on the head is there to protect us from sunburn. I've never seen a bald animal, so isn't evolution in charge of addressing these type of things? How is it that ...
0
votes
1answer
426 views

Are there examples of the green beard effect in humans?

Green-beard effects are genes that: Produce an effect that can be detected Produce preference to others with the same effect Are there any examples of this in humans?
4
votes
2answers
145 views

What is the purpose of the adrenal medulla?

The adrenal medulla is less of a 'real' endocrine organ like the others in the endocrine system and much more an extension of the sympathetic nervous system. In fact, its chromaffin cells are modified ...
5
votes
1answer
2k views

What are tendons made of specifically

From what I read on wikipedia they are made of collagen. Collagen is just a protein. Right? How is this collagen structured (I imagine like fibers). Aren't there cells in this fibers as well? From ...
3
votes
0answers
214 views

What is the timing of information assimilation within a human brain? [closed]

A little background: I'm an avid dreamer and have great dream recall, sometimes up to 5-7 per night. In my experience, I can sometimes trace some elements of the dream to an event that occured ...
3
votes
1answer
395 views

Could inhibition of progerin formation slow the rate at which a body ages?

According to wikipedia, progerin is activated in senescent cells. The protein itself is known to be the cause of a rare affliction 'progeria' - a disease marked by accelerated aging of the body. This ...
8
votes
2answers
165 views

Is there a consensus on whether or not race exists on a biological level?

The most recent survey I could find was from 1985 which said that 16% of biologist disagreed that "[t]here are biological races in the species Homo sapiens." I was wondering if there's been a change ...
1
vote
2answers
285 views

How are proteins formed?

Somewhere, I have read that we need to consume proteins to make amino acids to make new proteins. What does it suggest? How do we make proteins from proteins?
7
votes
2answers
266 views

Why do people have darker skin in sunnier climates?

I don't understand why darker skin is advantageous in hotter climates. Wouldn't it absorb more of the heat? I have heard that it reduces the incidence of cancer, but I would think absorbing more ...
7
votes
2answers
4k views

What are the consequences of voluntary total celibacy?

Psychologically this might be a tough question, but in means of biology, what are the effects of total celibacy on the gonads and the nervous system concerning both man and woman in short and long ...
-3
votes
1answer
596 views

How does protein help to cure wound? [closed]

I understand that the protein helps to repair body tissues. If I increase the intake of protein, would it help to cure the wound more quickly? I would like to know how does the protein reaches the ...
-2
votes
1answer
162 views

Why does a drop of water penetrate deep sleep? [closed]

Sleeping under the stars, a breeze carrying a few drops of water came by. The sense of water drops on my arms woke me up. I'm curious Why does the sense of a drop of water on one's body penetrate ...
7
votes
1answer
306 views

How fast do different organs turn over cells?

It is said that the human body turns over all cells or molecules in 7 year cycles. This is not quite correct, because there are different organs changing at different speeds. My interest is what is ...
0
votes
2answers
582 views

What part of food gives the blood red color?

Roughly, what I know is, when we eat food it goes into our: Stomach > Small Intestine > Large Intestine > Rectum. So, it just moves through a digestive pipe. What I don't understand is, what part of ...
3
votes
1answer
5k views

What is the functional difference between hemoglobin and ferritin?

I read that both hemoglobin and ferritin are for storing iron in the body. So, what is the difference between them in terms of storing/binding iron?
27
votes
2answers
507 views

Why don't teeth glow?

Hydroxyapatite is the main component of tooth enamel. It contains phosphorus in the form of phosphates, pyrophosphates etc. that are found to exhibit the the property of phosphorescence. But why don't ...
5
votes
1answer
541 views

Is there a relationship between efficiency of cellular metabolism and warm-blooded-ness?

My BIO 101 book states that when human cells convert glucose to ATP, the process is only approx 35% efficient, and much of the potential energy is lost as heat. However, that heat is useful to us in ...
6
votes
1answer
165 views

Understanding Membrane / Resting Potential from the perspective of ions?

From wikipedia article RESTING potential: "there is no actual measurable charge excess in either side. That occurs because the effect of charge on electrochemical potential is hugely greater than ...
9
votes
1answer
751 views

Why do we like salt?

A few friends of mine told me that salt provides zero nutritional value to us, and in fact can harm our bodies. Now, these guys are medical students, and being an engineering student myself, I decided ...
17
votes
1answer
811 views

Is kissing a natural human activity?

The word natural here is meant in contrast to it being a sociological construct. Is kissing in all its forms something natural for humans? Is it instinctively erotic? Or is it just a conventional ...
5
votes
2answers
232 views

Energy use by muscles, actual work done by muscles and more

Lately, I've started exercising in the gym and outside. I've also started to look at the details of food I eat. Food usually has a label saying the amount of energy is inside it. For example, some ...
8
votes
1answer
394 views

What causes knuckle “popping” and the feeling of relief that comes from it?

Many people like cracking their knuckles. I have always been curious about it. What happens when we crack knuckles? What creates the POP sound? Why do we get a relief-like feeling after doing it?
4
votes
1answer
126 views

What biological systems are affected by Vitamin B6 (or B vitamins in general)?

B vitamins and particularly the B6 vitamin appears to the one of the main ingredients in energy drinks. There has been anecdotal evidence from people interested in dreaming that ingestion of vitamin ...
2
votes
1answer
211 views

Why apes started to contemplate and become altruistic? [closed]

I was asking this first on philosophy forums, but it is suggested, that answer could be found from evolutionary view of point, so here we go: Again my question raised when thinking of myths, their ...
7
votes
1answer
188 views

Why are some menstrual cycles irregular?

A friend of mine asked me this today, and I didn't know. I remember studying the menstrual cycle a few years ago, but I can't remember the details (other than it was very hormone-related), and so I ...