Biology pertaining to humans.

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1answer
53 views

Is RGB diode lighting okay for the eyes?

Is a light source giving off light composed of red, green and blue lights harmful to the eyes? Does it lack any important qualities that other artificial light sources, such incandescent lamps or ...
8
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2answers
637 views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
5
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1answer
272 views

What could account for an apparent loss of mass at death?

An interesting tidbit floating around the internet these days is that Dr. Duncan MacDougall apparently weighed people shortly before and after death, and found an average of a 21 gram discrepancy, to ...
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4answers
9k views

How long human can survive with just drinking water everyday

Can humans live without eating food, just by drinking water? How long can we survive just by drinking water everyday?
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4answers
2k views

How long can a naked human survive on Mars?

How long can a naked human survive at the surface of the Mars planet? For instance, let's say a worker's base takes fire while he sleeps, and he has to run to the emergency building 200 meters away ...
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1answer
43 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
109 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
33 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 ...
2
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1answer
103 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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0answers
151 views

Size order of human organs

Wikipedia states that the liver is the largest internal organ in the human body. How does it relate to the sizes of ex. the lungs and small intestines? I've been having this personal image for years ...
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2answers
449 views

What organs are absolutely needed by the human body?

The title is my question: what organs are absolutely needed (fatal if injured/removed) by the human body and perhaps animals in general? I'm not asking which organs are mechanically replaceable, but ...
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1answer
77 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, ...
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1answer
230 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 ...
2
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1answer
64 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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0answers
67 views

Why do ion concentrations change with different secretion rates in pancreatic juice?

Why is it that when secretory rate increases in the pancreas the concentration of chloride ions decreases, and the concentration of bicarbonate increases in the production of isotonic NaCl secretion? ...
2
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2answers
177 views

What mechanism suppresses melatonin release in humans?

I'm looking at melanopsin, a photo pigment in the human eye. One of its actions is to trigger suprachiasmatic nuclei SCN to suppress melatonin release. I'm interested in learning what is the exact ...
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0answers
95 views

How does geography affect morphological features of the human body

I've seen many times how a person born in one place, goes to another country for a long time, and then they start looking more like the people there, but I never found out how it works. This report ...
2
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2answers
216 views

How to know if a woman is fertile without actually making her pregnant?

How to know if a human female is fertile (can give birth to child in future) without making her pregnant? Any signs, tests?
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1answer
65 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 ...
1
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1answer
866 views

What would be the best design for spike-and-recovery and linearity-of-dilution validation experiments in one 96-well ELISA plate?

I have searched in the web for a detailed explanation of doing such validation experiment, but unfortunately couldn't find a satisfactory one. I came across the following sources: Thermo ...
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0answers
68 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
23 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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0answers
83 views

Perception of distant lights without glasses

I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's ...
5
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1answer
1k views

Why does plucking nose hair cause tears in the eyes?

It's not a particularly sad or painful thing to pluck a few nose hairs, but it's common for the tear ducts to wet up when doing this. I would like to know the physiological reason for the ...
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2answers
2k views

What could cause hairs to gray at the tips but not the roots?

I have noticed that some of my sporadic gray hairs are gray at the tip side but oddly, not near the roots. Some are even only gray in the middle. I find all of this very counter intuitive, and I ...
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0answers
108 views

Are there nutritional benefits to drinking diluted urine?

I know that urine drinking is a widespread practice (with a long history). The main reason that people give today involves there being nutrients in urine. If there are nutrients to be gained, why is ...
2
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1answer
290 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 ...
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1answer
64 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 ...
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2answers
2k views

Why is that all the animals can swim in water without learning to swim but humans cannot?

I had a question since I was a child. I was always curious that all the animals can swim in water. They don't need any training or to learn swimming. But humans need to learn to swim. Why ? I am a ...
2
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1answer
57 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 ...
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1answer
242 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 ...
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1answer
74 views

Agony, Hydrophobia and viruses in the light of evolutionary principles

I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice. Agony as the last ...
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2answers
246 views

In humans what is the last metabolic process to cease after death?

After death which of our body's metabolic processes will continue functioning for the longest?
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1answer
132 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 ...
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1answer
362 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
90 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
90 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 ...
4
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1answer
1k views

Why do sneezes come in pairs or more?

I very rarely sneeze just once, usually there's two coming in a row, and I've noticed the same thing in other people and even in animals. Is there any reason for this?
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0answers
31 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
81 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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0answers
25 views

Are anti-inflammatories useful for tendinosis?

I am wondering why some doctors prescribe anti-inflammatory treatments for conditions that are supposedly not inflammatory such as tendinosis. From my understanding, only tendinitis a swollen tendon ...
6
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1answer
27k views

What causes random long white body hairs?

I'm sure many of you have experienced this - you scratch your back or brush your hand over your arm and find a ridiculously long thin white hair, sometimes as long as 3 or 4 inches. I know a few ...
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1answer
69 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 ...
2
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2answers
109 views

Lactose Intolerance

What nutrition is given to infants who are lactose intolerant? I understand, in today's day and that age we have non-lactose formula milk, but what happened, before lactose-free milk was created, to ...
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0answers
35 views

HSL Lightness vs Eye sensitivity

In a monochromatic spectrum, is the human eye equally able to distinguish between lighter colors just as it is in distinguishing between darker colors? I mean is there really a linear relationship ...
4
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1answer
171 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 ...
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3answers
143 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 ...
7
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2answers
404 views

Does every human eye see the same visible spectrum?

It is said that human eye can see light with wavelength approximately between 400nm and 700nm. Are these upper and lower bounds same for every human? If not, what are the means and standard ...
4
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0answers
4k views

Can a person really die quickly from biting their tongue?

A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible? The internet turns up millions of ...
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1answer
134 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 ...