Tagged Questions

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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1
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1answer
75 views

Is it possible to give a person an allergic reaction in a very specific place?

Can I give a person an allergic reaction at a very specific spot in a tissue? And if so, how accurate can i get?
1
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2answers
202 views

Why does throat 'burn' when you've got a common cold?

Apart from pain when swallowing, there's also a persistent feeling of throat 'burning' in the same area. What causes it and why does it feel that way?
2
votes
1answer
53 views

Trigger allergic reaction in non-allergic people?

Is there a proven way to trigger an allergic or allergic-like reaction in non-allergic people? I have wondered if this is possible, since allergies are basically just a form hypersensitivity - so ...
3
votes
1answer
159 views

Does an allergic reaction kill body cells?

I have wondered what actually happens in an allergic reaction that causes the symptoms such as pain, rash etc. Is it possible that the human body actually kills its own cells in the process?
0
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2answers
48 views

Manipulating Gut flora in vivo

I am tasked with designing an in vivo experiment in humans that requires manipulating the gut flora in one sample group to gauge its effect. Please suggest ways of doing this besides administering ...
5
votes
1answer
174 views

Why does strenous exercise cause vision of “lights”?

I had a hard climb a week ago. I got so tired then any time I closed my eyes I saw these lights inside my head. I see these lights almost every time that I run fast or some thing like that. What are ...
6
votes
1answer
180 views

How does skin healing work?

I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
7
votes
1answer
949 views

Can you consider a human as alive, or is it the cells on the body that are alive?

Sorry if this question seems strange, but in the recent time I have been interested in the question of what life is and how you can define life. My question: How long can individual cells live on a ...
9
votes
2answers
578 views

Which sex has higher variance of reproductive rate in modern societies - male or females?

Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
11
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4answers
4k views

What nutrients can humans absorb in the mouth?

For instance, I realise being able to absorb simple sugars in the mouth is pivotal in the rapid action of oral glucose gel. Thus I was wondering what nutrients in general can be absorbed directly ...
4
votes
1answer
108 views

Why do we yawn?

I've read a new study which suggests that yawning may help you keep a cool head. Also, the findings might hold some hope for sufferers of insomnia, migraines, and even epilepsy. Is there any ...
3
votes
1answer
237 views

The fundamental importance of R.E.M. Sleep. (Rapid Eye Movement)

Question: I know that experiments have been conducted to determine the importance of R.E.M. sleep in our sleep cycle. It is particularly important for learning, information synthesis, and recovery ...
2
votes
1answer
123 views

Why do cells have an average 'life span'

I've heard of Henrietta Lacks. As a result of a genetic mutation, her cells never died. I've heard/read that overtime, our cells stop multiplying as much, (as an effect of aging). Why? Why do we age? ...
2
votes
1answer
107 views

Why do genitals feel frozen when freefalling?

I don't want to add much more about that. Since childhood I noticed a chilling effect, even when doing rollercoaster-type activities.
5
votes
1answer
557 views

Is human face more resistant to cold than other body parts?

Walking outside tonight in -15˚C I realized an interesting observation: While I felt cold on most part of my body, my face (although the only uncovered part) didn't really feel cold. It registered the ...
8
votes
1answer
226 views

What prevents a pregnant woman's immune system from recognizing her fetus as nonself (and attacking)?

I'm familiar with the scenario of Rh- mother with Rh+ fetus having complications (more so after her first child), but that's not what I'm curious about. I want to know mechanistically why a pregnant ...
15
votes
2answers
4k views

Why is cold water more refreshing than warm water?

Obviously, the temperature of water does not affect its chemical composition. At least not in the ranges we are likely to drink it in. Yet it is clearly far more pleasant and refreshing to drink cool ...
6
votes
3answers
375 views

Why people like to see pornographic scenes, but do not feel the same about eating scenes?

This question may seem funny, but I think biology must have good answers. I think no more explanation is needed. I really thought about this and searched for an answer, but there is nothing yet. If ...
2
votes
1answer
1k views

Why does yawning impair hearing?

When I yawn I can't hear anything happening around me. I also feel some kind of muscles inside my head contract and hear a faint hum, but it is not loud enough to explain not hearing other sounds. I ...
2
votes
1answer
2k views

Which blood vessel carries the most impure blood?

There is a question in my Biology textbook: "Which blood vessel in the human body carries most impure blood after few hours of meal." The answer is given as Renal artery. But I think the ...
3
votes
0answers
86 views

What are the physiological effects of wine?

I have read that alcohol in general and wine in particular can have advantageous as well as detrimental effects on human health. Is this true? What are the physiological effects of consuming wine in ...
3
votes
1answer
122 views

Where does all the food go?

Food goes in, excrements come out. This seems obvious. But it seems like the mass of the excrements is less than the one of the food. Most people I asked answered: "There's a difference because it's ...
5
votes
2answers
2k views

How does HCl does not burn our stomach?

How does the digestive acid (HCl) not burn the surrounding skin of our stomach? It digests majority of raw food we eat but how does it stays safe in our stomach? Also, how does the stomach retains the ...
4
votes
1answer
112 views

What kinds of arousal can a human brain experience?

I've been reading about the new phenomenon called "arousal addiction". The context in which this term is used is Internet, Porn and/or video game addiction(cummulatively Internet Addiction Disorder - ...
7
votes
2answers
8k views

At what age do babies begin to synthesize their own antibodies?

When babies are first born, they receive their antibodies from their mother (I assume because they do not yet have the capacity to synthesize their own). So my question is, at what age do babies ...
4
votes
2answers
265 views

Effects of exercise on the brain

I am well aware of the phenomenon of neurogenesis induced by exercise, as well as the dopamine release that results from exercise. I am really interested in neuropsychology and the effects of exercise ...
1
vote
1answer
50 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 ...
8
votes
2answers
615 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 ...
13
votes
2answers
6k 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 ...
4
votes
1answer
569 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.
6
votes
2answers
8k 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
votes
1answer
9k 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
votes
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
votes
1answer
65 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
votes
1answer
1k 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 ...
4
votes
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
votes
2answers
113 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 ...
1
vote
1answer
112 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. ...
2
votes
0answers
41 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
votes
1answer
326 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 ...
1
vote
0answers
84 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
vote
1answer
70 views

Can gelatine digestion make blood more thick?

Can gelatine cause blood thickening if digested?
3
votes
1answer
68 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?
5
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2answers
5k 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
votes
2answers
745 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
votes
1answer
127 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 ...
1
vote
1answer
33 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?
-2
votes
1answer
87 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
votes
1answer
66 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
votes
1answer
234 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 ...