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
47 views

I'd like to know the name and a few details of a certain time-keeping structure in the human brain

I once heard of this structure on the Discovery Science channel and have since forgotten the name. The details I remember about it were that it is the central time-keeping device for the brain located ...
5
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1answer
148 views

Do lunar rhythms have impact on human biology, if so, how?

I'm approaching this question from the circadian rhythm perspective. A circadian rhythm is a 24 hour cycle. While doing research on deep sea circadian rhythms, I found this abstract which seemed to ...
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0answers
44 views

What processes are responsible for focusing on an image only seen by one of the eyes?

When a person is spying from around a corner with only one eye, it's rather easy to ignore the other eye's image, since it's probably much darker, because one usually spies around a corner standing ...
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1answer
134 views

Is there a comprehensive list of human circadian-like processes, hormones or gene expressions?

I'm reading this article onblood sugar and circadian rhythms and the following question popped into my head: a lot of articles mention various diurnal or circadian rhythmicity of biological processes. ...
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1answer
419 views

What are the long-term negative effects of going without water/food for a period of time [closed]

There are no good answers anywhere. so asking: this is not about days of survival without water. This is about long-term negative effects induced from not drinking water for at least the mentioned ...
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1answer
117 views

Could a person become physically transgender through artificial means?

Let's say there's a girl who carries a few masculine traits not normal in most girls, such as a high level of testosterone; we know there are countless reasons why something like this could happen, ...
2
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1answer
71 views

Why it is so difficult to treat leukemia?

I want to ask what is the reason that T315I type CML leukemia is currently untreatable. I have read quite a few papers in this subject. Why the current genetic oriented engineering drugs failed to ...
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4answers
2k views

Can two humans with 44 chromosomes produce viable offspring?

It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes. One example is a male in China: the first article, the second article. The other is a female in ...
2
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1answer
76 views

Whence fecal E. coli (et al.) if swallowing it is dangerous?

I don't know much about medicine, and I know even less about microbiology, but I understand that there are organisms in the lower gastrointestinal tract (and in feces) of a human, like Escherichia ...
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2answers
405 views

Below which temperature human muscles don't work?

When one exposes theirs body parts to cold environment (especially foot and hands), they may be numb, with temporarily blocked both muscles. What is typical body temperature below which human muscles ...
2
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0answers
94 views

How do omega-3 fatty acids reduce cholesterol at the molecular level?

I have heard that omega-3 fatty acids found in fish are a good way to prevent/reduce cholesterol problems. My question is how do omega-3 fatty acids do that: what are they doing on a chemical level ...
0
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1answer
28 views

Is there any relation between weight class and extreme lifting performance in O-lifting?

We usually thought that weightlifting is a tough game. It is only for great physique. There are 6 man in history who lifted 3 times their body weight. Check here. 3 of them are Bantamweight(56kg), ...
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1answer
337 views

Can Naegleria fowleri enter through the eyes ( example rinsing/splashing eyes with water)

I understand that it primarily enters the body through the nose by by "feeding on the olfactory neurons in the nose" as answered here in a different question. Would the nerve cells in the eyes present ...
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1answer
90 views

Is there an optimal illumination level for human habitats/workplaces?

I know of melanopsin, a photo pigment in mammal eye that helps regulate circadian rhythms. It responds most strongly to blue spectrum light. There have been experiments that demonstrated that ...
2
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1answer
506 views

What controls the breast size?

I am not a biology student, just a curious person. To be specific, I'm talking about humans and specifically about females. I know that it might apply to other mammals. What controls the size of ...
2
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1answer
69 views

Are (baseline) high blood levels of melatonin associated with either circadian rhythm or mood disorders?

(Exogenous) melatonin is administered at night for treatment of circadian rhythm disorders, but melatonin taken during the day is linked with depression. I would like to know if high blood levels of ...
1
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1answer
690 views

Relation between goose bumps and temperature

As we all know, cold weather will cause us to have goose bumps. I honestly don't know why (1), because our skin contracts? Apart from that something quite contradicting happened this morning. I was ...
9
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2answers
758 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 ...
11
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1answer
172 views

Does sleep in humans re-structure based on the expected sleep time?

I've read about anecdotal evidence that human brain has a fairly good internal clock that can be used to judge the amount of time that has passed. I'm wandering if there are any mechanisms in the ...
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1answer
200 views

Are there any viruses or bacteria which have evolved to withstand higher temperatures due to fever

My question was raised after receiving this information: The primary reason the body raises its temperature (via the Hypothalamus in this case) is that bacteria and viruses tend to optimally ...
5
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1answer
676 views

If fever is a natural immune defense, why do people take drugs to lower it?

If fever is a natural defense against pathogens, why do sick people take NSAIDs to reduce the fever?
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1answer
142 views

How much can be said about behaviour (future) based on bloodgroup?

My bloodgroup for example is A+. How much information is knowing my bloodgroup? How much information can be known from a blood sample? I expect you to be able to clone if known a complete DNA sequence ...
5
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1answer
101 views

Can cirrhosis be caused by physical compression of the body?

On a random forum, a member speculated that their cirrhosis was caused by wearing tight-fitting clothing such as a girdle or corset. This leads me to the following question: Question: Can ...
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2answers
3k views

Will humans and animals be harmed by frequencies outside their hearing range?

The human ear (for example) is sensitive to frequencies from 20Hz to 20kHz. Any sound beyond that limit would not be heard by us naturally. Will it harm us (effect our ability to hear) when we hear ...
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0answers
40 views

Can a sound frequency 'not' within human hearing (20 Hz - 20 kHz) damage hearing when it is of high volume? [duplicate]

We can't hear sounds outside the range of 20 Hz - 20 kHz. However, if an inaudible sound is played at high volume, will one's hearing be affected?
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1answer
89 views

What in soy are people allergic to and will these allergens be passed along if an animal that has eaten soy is consumed?

I have two related questions about soy allergies and possible reactions. What is it that are humans who have soy allergies actually allergic to? What is the allergen? If an animal eats soy, are ...
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1answer
247 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 ...
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1answer
75 views

Are there any studies of epigenetic difference between twins during their lifespan?

Are there any studies of epigenetic difference between twins during their lifespan ? I ask because I wonder if there exist phases during lifespan, when environmental factors plays major role ...
4
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1answer
322 views

Does frequency of eye blinking reveal anything about human biology/nervous system?

I'm looking at an output of a single dry sensor EEG headband with the sensor positioned above left eye. As a side effect of it's placement, the device picks up eye blinks, and some eye motion as ...
5
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3answers
187 views

What are the limitations of commercial-grade DNA genotyping compared to full sequencing?

I've heard about services like 23andme, which offer genetic testing to the general public. As a person who knows very little about genetics, I'm interested in the subject and would like to know what ...
5
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1answer
213 views

How can the child and the mother have different blood types?

As far as I know the fetus is fed by the umbilical cord which basically connects his/her circulatory system with the mother's in order to supply oxygen and nutrients. But how is this possible if they ...
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1answer
234 views

Are lactic acid and prolactin rise after exercise connected?

I've been reading about prolactin, a human hormone. Apparently it's levels within the brain can raise after exercise, although the mechanism is not clear to me. I'm interested of there is any ...
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1answer
78 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?
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2answers
215 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?
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1answer
56 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 ...
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1answer
195 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?
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2answers
49 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 ...
10
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3answers
390 views

Athletes: nature vs. nurture?

Having watched a lot of olympians the last few weeks, I was struck by how many of them have actually spent their wholes lives/careers training for their one event (be in running a marathon, or ...
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1answer
120 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. ...
6
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2answers
462 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 ...
4
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1answer
114 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
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1answer
272 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
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1answer
150 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? ...
6
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1answer
345 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 ...
2
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1answer
136 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.
3
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1answer
136 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 ...
4
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1answer
120 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 - ...
4
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2answers
319 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 ...
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1answer
1k views

What influences the timing of human bowel movements in the morning?

I'm trying to understand if the timing of human bowel movements in the morning is associated with the circadian rhythm, and can thus be used to make predictions about the circadian rhythm. What ...
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1answer
102 views

Does artificial heat (shower/tea) affect diurnal rhythms in humans?

I've been reading that over the course of the day, human body temperature follows diurnal rhythm with the lowest body temperature observed some time close to the middle of the sleep episode, while the ...