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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2
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3answers
119 views

Is it possible to make humans extinct artificially?

Verging on the realm of science fiction, my question is that is there any theoretically possible way, biologically/chemically, with which the entire human race can be killed without affecting the rest ...
5
votes
1answer
71 views

Diabetes-diabetes comorbidity

Is it possible to have both type-1 (insulin-dependent) and type-2 (non-insulin-dependent) diabetes mellitus? That is, to have both insulin resistance and zero (or negligible) insulin production? If ...
2
votes
1answer
126 views

How can we distinguish blended flavors?

As far as I know, humans can distinguish between 5 basic tastes based on various molecules in food and their interactions. There's a level to all 5 so there can be an endless variety of tastes, and we ...
3
votes
3answers
21k views

What is it called when one human eye is seeing brighter color than the other?

What is the name of a phenomenon where one of the human eyes is seeing brighter/more saturated color than the other? I can observe the same object from the same position while alternating which eye is ...
1
vote
3answers
91 views

Are there “multi-frequency” signals within a human brain?

I know that neurons can exhibit tonic and phasic firing, and also that a neuron is sometimes called an integrator. This makes me interested to know if there are activities in the brain that depend on ...
4
votes
2answers
14k views

What happens to the holes in the skull where teeth were developing?

In Skeptics.SE, a question regarding the skulls of children arose. Depicting a scary skull where the permenent teeth are "hidden" inside the jaws and the milk teeth are in the their place. After all ...
15
votes
2answers
415 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
2
votes
1answer
2k views

fibroblast cells and fibers

I am interested in fibroblast cells in human arteries. Here are the things that I am not clear at the moment and I could not find any answer from the literature: What are the dimensions of these ...
6
votes
1answer
4k views

What causes the colors we see in eyes?

Genetics aside, what are the biochemical reasons the different colours of human irises? Also, related, how does eye colour change, particularly in childhood? (example: my eyes used to be blue, ...
9
votes
1answer
812 views

Could humans and chimpanzees hybridize?

In some cases two species can hybridize. For example, Tigers and lions can hybridize to produce "Ligers". Would it also be possible for humans and chimpanzees (or any other species) to hybridize ? ...
3
votes
0answers
265 views

Can someone explain the color-changing unit (CCU) to me?

I've been physically carrying out serial tenfold dilutions on samples of Ureaplasma to work out the color-changing units (CCU). As a definition, the CCU is the highest dilution at which there is a ...
1
vote
1answer
56 views

What are the biological and nutritional benefits of having numerous smaller meals a day?

I have heard here and there that instead of consuming 3 largish meals (the traditional 3 meals a day), that consuming several smaller meals throughout the day is beneficial for health (and weight ...
0
votes
1answer
39 views

Distribution of nutrients throuought a drink made of plants?

In an attempts to eat my veggies for the day in one shot, I blended together a bag of salad with some water. The mixture separated by density, a thick top layer containing the bits of leaves, and a ...
7
votes
2answers
529 views

Do teeth have the capacity to heal?

Could a cavity in a human tooth "heal over" or possibly fill back in?
3
votes
1answer
169 views

Differences between right and left handed people

Are there any articles reporting any significant differences in behavior, attitudes, intelligence, appearance, etc., between right and left handed people?
7
votes
1answer
1k views

How do people who have lost both of their legs produce red blood cells?

As far as I know, just leg bones produce red blood cells. So, how people who lost their both legs produce red blood cells?
2
votes
1answer
748 views

What do rs id, allele coded 0 and allele coded 1 mean?

So, for a project I've been working on (different story), I've been looking at the HapMap Project, and their free online files. In their README file, they talk about how for each legend file for each ...
2
votes
2answers
98 views

E. coli, risk of infection?

There has been a warning about E. coli contaminated water in South Florida. Now I'm wondering are there empirical data or historic cases which show a correlation between E.coli levels in tap water and ...
2
votes
2answers
8k views

Can the excessive consumption of mineral water lead to kidney stones or other health issues?

I heard that drinking too much mineral (bottled) water could lead to problems such as kidney stones because of the high amount of minerals in it. Is it true? If so, what is considered to be excessive? ...
0
votes
1answer
2k views

Structure of adenoids

I am not sure this question belongs in biology, but I can't find a more suitable stack exchange site, feel free to delete it if this doesn't fit here. Also, this question is going to be slightly ...
2
votes
0answers
63 views

Movement of stem cells from mother to fetus

Recent results from J Lee Nelson and colleagues (Sci Am. 2008 Feb;298(2):64-71; available as full text through Google) show that cells from the mother were found in a person aged 46. Logically, these ...
1
vote
0answers
49 views

What parts of the brain are involved in regulating blood pressure in mammals?

I'm reading this Wikipedia article on blood pressure and its regulation, and it mentions that medulla is involved. however, I vaguely remember reading another article on Wikipedia and it mentioned ...
1
vote
1answer
430 views

How do changes in temperature affect body weight in humans?

What would be effect on weight of individuals if we bring a fully adapted (to cold climate ) human individual and a fully adapted to very hot climate individual to a moderate climate region?
-1
votes
1answer
633 views

Are we evolving to age slower, or to live longer aging at the same rate?

I wonder why most of us find senior people lovely and charming. Is it because to love grandpa and granny is vital to our survival as a species, in the same way as we love babies? If so, it would mean ...
2
votes
1answer
184 views

Can antibodies be formed against white blood cells after blood transfusion?

If antibodies are produced against other blood groups' red blood cells, why can't antibodies form against white blood cells, of any blood group? (even the same one, as MHC will be different in almost ...
2
votes
1answer
2k views

Ammonia smell after physical exercise? What is the explanation? [duplicate]

After exercising vigorously one can sometimes smell ammonia and it feels like it's coming from within the nose actually. There is no indication that others can smell it when I do (i.e. seems to be ...
3
votes
3answers
239 views

Blood pressure during exercise

What happens to blood pressure when we exercise? Does it increase, decrease, or remain the same? If it does increase, why are patients with high blood pressure recommended to exercise?
4
votes
1answer
368 views

Would a spinal injury decrease human height?

A woman I know has been losing height at a rate of few cm a year following a severe spinal injury. How is this possible? What kind of injury could cause such progressive loss of height? Could this be ...
3
votes
2answers
2k views

Ill effects of urea and NH₃ on metabolism

What exactly does urea do that harms our body? Does it interfere with our cellular processes or disturbs the colloidal onchotic pressure of our blood? I have heard that NH3 damages the brain. What ...
1
vote
1answer
116 views

copper spiral birth control not toxic?

I Always thought that copper was toxic to the human body. So how can it be safe to place a copper object (birth control spiral) into a uterus for a duration of 5 years?
2
votes
0answers
54 views

How to use mechanical microstrainer to extract tissue proteins from human? [closed]

Background: There are many methods to extract proteins form human tissues out there. The majority of them use an extraction buffer containing variable concentrations of detergents and protease ...
5
votes
1answer
177 views

What effect do oligosaccharides, like those found in legumes, have on the composition of intestinal flora in humans and if so how so?

I know that intestinal flora metabolising oligosaccharides, like those found in legumes, is the cause for the well known fact that legumes cause flatulence, but does an oligosaccharide-rich intestine ...
8
votes
1answer
810 views

Why does it hurt more when you touch a nerve directly?

I am not a biologist nor know much about biology (so please explain in layman's terms) however I have always been curious as to why this is. What causes the difference in pain between touching an ...
10
votes
3answers
1k views

How are our senses dimmed during sleep?

Our senses are not as sensitive during sleep compared to wake. There is an arousal threshold during sleep that only when it is overcome will it wake a person up. My question is how is this arousal ...
2
votes
1answer
505 views

Why is the blood pressure in the superior vena cava during inhalation less than during the exhalation? [closed]

For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart ...
2
votes
1answer
106 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 ...
10
votes
2answers
3k 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
votes
1answer
495 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 ...
5
votes
4answers
50k 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?
6
votes
4answers
9k 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 ...
1
vote
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
votes
1answer
156 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 ...
8
votes
1answer
74 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
votes
1answer
152 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. ...
2
votes
3answers
3k 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 ...
0
votes
1answer
135 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, ...
-3
votes
1answer
479 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
votes
1answer
74 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 ...
2
votes
1answer
138 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
votes
2answers
354 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 ...