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
44 views

Does difference in expected life duration between men and women have biological nature?

It is known that men in most countries live less than women. I wonder whether it is due to different life conditions or because male and female organisms differ? For example, I heard that ...
7
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2answers
527 views

Do hormone drugs affect whether a person feels sexual attraction to males or females?

I know that ingesting testosterone and other hormonal drugs may stimulate libido and increase sexual desire. But I wonder, if a man ingests female hormones such as estrogen, will he experience sexual ...
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2answers
4k views

Why do people have antibodies against other blood types?

The ABO blood type divides each blood type according to whether they have the "A" and "B" antigen(s) (AB has both, O has none). People also have antibodies against the antigens they don't have (AB has ...
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1answer
453 views

What causes Acne?

What exactly is going on biologically at the molecular level with acne and causes breakouts? Hormonally, there is a lot going on but I'm curious about what is going on chemically.
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2answers
7k views

Can positive and negative blood type of a couple lead to miscarriage?

I want to know can $+ve$ and $-ve$ blood group of a couple could be a cause of miscarriage in pregnancy?
8
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1answer
7k views

What is the composition of human feces?

Are there any studies or general information on the composition of human feces? I'd specifically like to know the percentage of carbohydrates and amino acids relative to the amount that was ingested ...
5
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1answer
61 views

Is the eyes' movement discrete?

When tired and it was dark, I noticed that if I focused on a dim light source and moved my eyes fairly rapidly sideways, the resulting images that lingered for a short while were not smoothly blurred ...
2
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1answer
63 views

Do siblings have a bias toward believing they look different from each other?

Anecdotally, I have observed (myself included) that siblings tend to think that they look less similar to each other than an unrelated observer would say. Is there any experimental data to back this ...
5
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1answer
549 views

How much gas is exchanged in one human breath?

When we breathe, our lungs absorb a portion of the oxygen in the air, and replace it with some amount of carbon dioxide and water vapor. Typically, how much $O_2$ (in grams, milliliters, or moles for ...
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1answer
2k views

How does prolonged exposure to high frequency noise affect hearing?

Is there any research showing how prolonged exposure to background noises, particularly high frequency noises, affect hearing abilities? Does constant high pitched noise cause damage even a low ...
2
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2answers
108 views

Can a new Y-chromosome be created?

The major gene of the Y-chromosome is SRY. Would it be possible to get the X-chromosome and add SRY to create a "fuller" Y-chromosome? What advantage does the skinny Y-chromosome give an individual ...
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1answer
102 views

Interlocus Contest Evolution means suicide?

I was reading Matt Ridley's "Genome" book. I am trying to understand the Interlocus Contest Evolution in his X-Y chapter. I do not understand why the X and Y chromosome would want to kill each other. ...
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0answers
37 views

Is there an entry-level circadian model of serotonin, ghrelin, dopamine and the sense of well being?

I've long been interested in circadian rhythms and recently came across a variety of articles that appear to indicate that the following neurotransmitters, transferases and hormones are connected. ...
3
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1answer
249 views

Are there records of monozygotic twins in which one experiences androgen insensitivity syndrome

I have given my high school biology students the thought experiment of "What would happen if a researcher induced twinning of a female zygote and then replaced one of the X Chromosomes with a copy of ...
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0answers
72 views

Why do people feel extreme cold at different temperatures compared to other people of same body structure?

I have seen some people shivering in the room temperature of 18°C while others of similar body structure do not feel that much amount of cold. Of course the clothing of both people is similar if ...
1
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1answer
53 views

Can gelatine digestion make blood more thick?

Can gelatine cause blood thickening if digested?
3
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1answer
67 views

Can frequent ultrasound diagnostics be harmful?

Are there any short or long term effects apparent in tissues if a zone (or the whole) of human body is scanned with ultrasonic waves often?
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2answers
4k views

Why can't you taste food when you have a cold?

It is a common observation that food is tasteless when we have a cold. Why is that so? What is the cause of inability to taste when we have a cold? Are the nose and ability to taste connected?
3
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2answers
546 views

Physiological indicators of happiness and well being

If I understand it correctly, levels of serotonin in the brain can indicate if a person is happy. What other physiological measures indicate happiness or well being for a humans? I am looking for ...
4
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1answer
100 views

Are serotonin levels in humans affected by light?

I'm reading this Wikipedia article on light therapy and noticed a peculiar statement: The production of the hormone melatonin, a sleep regulator, is inhibited by light and permitted by darkness ...
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0answers
16 views

What are studies linking dietary choices over life with probability of reaching higher ages?

Are there big studies that link diet and lifestyle choices with the probability of reaching a certain age? What are their conclusions?
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1answer
82 views

Good place to ask health based questions? [closed]

I like the development of biology.stackexchange.com, but it is still in an early stage and far from perfection. While we develop it further, could you guys help me finding places to ask questions ...
2
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1answer
63 views

Are humans hardwired to continue gathering resources after the costs outweigh the benefits?

An animal will stop foraging in a berry bush if the perceived cost of searching for berries remaining is greater than the cost of finding another bush which isn't as picked over. People do the same ...
6
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1answer
178 views

Is there a normal human melatonin concentration to light level curve?

I'm looking for a graph or a curve that would show the typical concentration of melatonin in blood or saliva for humans over 24 hours. It would be good to know the photoperiod for the same human as ...
6
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2answers
129 views

Is warmth/temperature sensed linearly or on a different scale?

I understand that the atmospheric temperature is sensed relative to external body temperature. However, is the sensation of warmth registered linearly, or is it on a logarithmic scale, similar to ...
9
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1answer
373 views

What light intensity starts melatonin release in humans?

I'm interested in whether any studies have determined the intensity of light at eye level that starts melatonin release in humans. I know that: melatonin release is suppressed by blue light with ...
6
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3answers
539 views

How to map the Gene name to its Gene Symbol?

I am learning in Gene data lately so I apologize for the silly questions in advance. I read a paper for a cancer on human which found some important genes. For example, the paper listed one of genes ...
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0answers
112 views

Can dry air make a person more prone to catching a cold?

I'm interested if there is a correlation between room air humidity and risk of catching a cold.
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3answers
3k views

Can a human smell through the ears?

The title does, prima facie, appear absurd. Performing a swallowing action whilst pinching the nostrils shut gives the impression of listening through a bucket filled with water around the head; ...
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2answers
1k views

What is the inlet/outlet speed of air going in/out of our mouth during inhalation/exhalation

During inhalation, your alveoli expand, creating a pressure difference between the atmosphereic pressure and our lung sacks and therefore air will flow into the repspiratory airways. I am trying to ...
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3answers
1k views

Where does the 'C' in exhaled CO2 mostly come from?

When a human being exhales $CO_2$, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
8
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2answers
404 views

Do memories have mass?

If it were possible to live forever, would our brains grow infinitely with the number of memories that we store? Or would we remove old memories as we create new ones?
8
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2answers
499 views

How much weight/volume do microbes occupy within the human body?

Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out. ...
7
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1answer
99 views

What happens when we know that there is something that we forgot but we can't remember what it was?

I think it happens for everyone that sometimes we go to a room and forget why we went there. Is there any research or article on this?
7
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2answers
2k views

Is nicotine toxic to humans?

More specifically, is nicotine in the concentrations that smokers receive when smoking cigarettes toxic? I know that in great enough concentrations it can be toxic (but then, so can just about ...
7
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2answers
211 views

How does the body measure dehydration?

What, physically, does the body do to measure it? I assume it's measured by how how turgid or plasmolysed certain 'sample cells' are, or water concentration in the blood, What is the way they use to ...
2
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1answer
58 views

Is it more likely to develop a throat-ache at night?

I have noticed that I rarely develop phlemmy throat-aches in the daytime, but often notice them after I have been sleeping. Is this a recognised phenomenon? Could it be because viruses or bacteria ...
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0answers
50 views

Do humans have chemosensors for nutrients or chemicals?

I'm reading about chemoreceptors on Wikipedia, and see that the typical ones are mentioned: taste, smell, co2. I would like to learn more about the other kinds of chemoreceptors that humans may ...
8
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2answers
426 views

Would exposure to a strong magnetic field have deleterious effect on the human?

This article states of a 25T magnet, ".. If are ever caught in one of these devices, let’s just say you probably won’t live to tell the tale." Is the above statement in order? What effect would ...
4
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1answer
127 views

Functionality of vitamin A, Bx, C, D, E, K as used in cosmetics for the skin?

I was wondering if someone can compare the functionality of vitamin A, Bx (x means numbers, such as 1, 2, 3, ...), C, D, E, K in the skin? They are used in cosmetics but what is their actual effect? ...
3
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1answer
305 views

Do adipose cells divide in adults?

I have a dim recollection of having heard that when humans gain weight, adipose cells just get larger, rather than dividing. True?
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1answer
59 views

In a human, what non-germline cells have the highest/lowest mass?

I'm just curious which cells are largest/smallest in the human body other than sperm/ova.
3
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3answers
546 views

What makes urine smell acrid?

Occasionally, after someone's been, there is an awful acrid smell lying about long after them. What causes this? The food that they've eaten? Urea less dilute due to dehydration? If it helps I've ...
6
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1answer
5k views

Will a bone marrow transplant change one's blood type?

Will a bone marrow transplant change one's blood type? Or is the donor blood type matched with the person before transplant?
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3answers
407 views

Is there such thing as “half-life” of dopamine?

If a dopamine is released at T=0 and binds to receptor D2, what determines the time when the concentration of this neurotransmitter bound to the receptor reaches half of the original concentration? In ...
4
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1answer
293 views

Do effects of caffeine on human body change with habitual use?

I've been reading about homeostatic nature of a lot of neurobiological processes - the brain is trying to maintain a balance by desensitizing receptors, re-uptaking and breaking down ...
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4answers
20k views

What is the armpit hair for?

Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
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1answer
154 views

Are inflammation and anxiety connected?

I've been reading a curious paper about the use of cannabis, and one of the passages piqued my interest: There’s also been a lot of work done on another constituent of marijuana, cannabinoid, ...
4
votes
2answers
424 views

Does the brain and the body use the same energy source (glucose/ATP)?

I've heard that the brain consumes quite a lot of oxygen and energy, compared to the rest of the body. What I'm interested in is if this is the kind of energy and oxygen that the rest of the body ...
2
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0answers
131 views

Virucides - Herbal and otherwise, for HHV6 type virus or any inner-cell virus

Does anyone know where I can find a reliable list of virucides (not anti-virus) that can be used by humans? This virucide must be able to affect viruses that are already inside the cells. St John's ...