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
2k views

Near point and far point of myopic eye

Suppose a person wears the specs of power -6D, the far point for that person is 16cm. But the near point of normal eye is 25cm. So, is the near point of a person with myopia (having far point less ...
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2answers
165 views

Advantages of pain sensation?

The hazards of congenital insensitivity to pain (CIP) are well-known. This question is about the obverse: what selective advantage, if any, does the normal sensation of pain confer? I'm thinking of ...
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2answers
8k views

Mitosis in human body

I've heard that stomach lining has the fastest reproducing cells and the brain has the slowest. Where in the human body does mitosis occur and at what rates do these cell reproduce? Is there a chart ...
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1answer
397 views

Influence of alcohol on brain cells

As I am not related to biology, I would appreciate if you can keep your answers as simple as possible. My question is about the influence of alcohol on the brain. As far as I know, drinking alcohol ...
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1answer
285 views

Consequence of touching Formaldehyde

I accidently touched formaldehyde some days ago. Skin on my hand got dehydrated as if I had placed it in salt solution. I washed it with water and it returned to normal state after 5 minutes. But now ...
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1answer
240 views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
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2answers
159 views

Is solving cancer required in order to avoid aging?

When the telomerase enzyme is not active the telomere shortens every time the cell duplicates leading to a reproductive limit (Hayflicks limit). On one hand this is a believed reason for aging. On the ...
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1answer
3k views

Do we actually get more sick (flu/cold) during winter?

The word flu derives from the Italian phrase "influenza de freddo" meaning "influence of the cold". Indeed it is that time of the year when my colleagues seem to have the flu/cold more often than ...
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1answer
41 views

Functioning of BCG vaccine

I read (from Nature Volume507, S4–S7 (06 March 2014) : For reasons that are poorly understood, BCG protects only infants; it is ineffective in older children and adults. Its efficacy also ...
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1answer
26 views

Association of shorter telomeres with heart disease

From this paper Those with shorter telomeres in blood DNA had poorer survival, attributable in part to a 3.18-fold higher mortality rate from heart disease (95% CI 1(.)36-7.45, p=0.0079), and ...
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2answers
312 views

What is the eye muscle status when you stare at distant view through a glass wall?

The book said when you look at object close to you, the eye muscles contract and vice versa. I wonder what will be the status of the eye muscles when I stare at distance view (such as a mountain) ...
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1answer
87 views

How many different smells can a human recognize?

How many different smells can a human recognize? If the space of smells is not discrete, how many dimensions it has (for example, the space of colors is three-dimensional).
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1answer
141 views

Evolution of Homo Erectus to Homo Sapiens

I just read an article on Wikipedia and noticed that some similarities between Homo Erectus and Homo Sapiens in the "Comparative table of Homo species". My question is; Is it possible to say that ...
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1answer
61 views

Is it easier to burn a calorie of fat or a calorie of a carbohydrate?

Say someone eats 100 calories of chocolate vs. 100 calories of carrots. Something tells me that eating the chocolate will lead to you generating more fat. Will it? Is it harder to burn the calories ...
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2answers
315 views

How does a veggie-less diet affect the human body?

I have some question, which I'm sure would fit better in the fitness section but proper answers should probably come from someone that knows biology. My question is rather simple. How can a person ...
3
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1answer
343 views

From a purely biological perspective, how does an optimal human diet look? [closed]

There is hardly any subject as contested in the media as what humans should eat. Usually, such discussions are devoid of actual scientific reasoning, though they all claim to be backed by scientific ...
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1answer
202 views

Raising two legs together while lying on bed

Let's do some exercise(duh!) Ok so lie on the bed. Lift your left leg. Put it down. Lift your right leg.Put it down. Easy? Now lift your left leg and without putting it down, lift your right leg. ...
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1answer
218 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
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1answer
43 views

Surrogacy Post Fertilization

The wikipedia page on surrogacy highlights two main forms of surrogacy: Traditional Surrogacy and Gestational Surrogacy. Traditional surrogacy inseminates the surrogate mother with sperm, while ...
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1answer
1k views

Is urine dirty as soon as it leaves the human body?

Human urine is sterile as long as it is in the human body. But is it dirty after leaving the human body? Could you get sick from it, if you drink it or don't wash your hands, for example?
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2answers
162 views

Electronic cigarettes (e-cigs), any health risks?

Background: An electronic cigarette (e-cig or e-cigarette) is a battery-powered device which simulates tobacco smoking patented in 1963 by Herbert A. Gilbert. It generally uses a heating element ...
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3answers
30k views

Healing process in mouth wounds

When we have an external wound the wound generally tents to clot and there is a layer of solid scab formed. Now,Yesterday while brushing my teeth i somehow hurt my gums and it got all bloody but ...
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0answers
45 views

Nearly Exhaustive List for Cholesterol Pathways [closed]

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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2answers
3k views

How do we know that everybody's DNA fingerprint is unique?

How do we know that everybody's DNA fingerprint is unique? I know, I know, everybody's DNA is unique. But when we do DNA fingerprinting, we're looking at very specific regions of high variability. ...
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2answers
95 views

Improving myopia

I have a friend who no longer needs glasses. He previously had myopia in both eyes but over the years it has improved until he no longer needs glasses clinically. He's had glasses for over 30 years ...
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1answer
54 views

Is there a scientific name for the field of study focusing on the hemispheres of the brain and their control of opposite sides of the body?

I'm assuming this field of study would focus on motor controls, movement, and exercise, but it could also focus on activities which strengthen the corpus callosum or stimulate a specific half of the ...
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0answers
272 views

Do Asian women have more difficult births than Europeans?

I recently heard a claim that Asians in general have more difficult births than Europeans. Is this true? I have found a few studies(1,2) on the effect of ethnicity on birth outcomes but they seem to ...
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2answers
98 views

Why do humans circulate monosaccharides instead of disaccharides as in plants?

Plants transport food mostly in the form of disaccharides like sucrose but humans transport them in the form of a monosaccharide - glucose. What is the reason behind this ?
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2answers
231 views

Why do most breast cancers occur in women?

According to Korde et al. (2010): Male breast cancer accounts for less than 1% of all cancers in men and less than 1% of breast cancers. This raises the question: Why do most breast cancers ...
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2answers
167 views

Systemic sensory confusion?

Sometimes when a person gets touched on one part of the body they feel it else where and may think it came from a different part of the body. What causes this? Other examples are similar to why you ...
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2answers
296 views

How does the brain know where a signal came from? What is the addressing system

I am an electronic engineer so I am thinking about this from an electronics outlook. How does the addressing system work, As I see it, the nervous system is small parallel branches attached to larger ...
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2answers
139 views

Chills down the spine with certain music?

I am sure many of us know the feeling of that tingling chill down our spines when listening to certain music. I experienced this most when my younger brother played an emotional piano piece for a ...
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1answer
4k 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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1answer
87 views

How usable is the Human Metabolic Model to predict biomass?

In order to use the Human Metabolic Model for Flux Balance Analysis of specific cancer cell lines, we would like to know what sort of flux values have been determined for the Human Metabolic Model. ...
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1answer
42 views

What are good data on the Human Metabolic Model and where can I get them?

Trying to get a good SBML representation of the Human Metabolic Model for use in Flux Balance Analysis and drug targetting (i.e. gene knockout) simulations. What are good sources for these data? ...
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1answer
183 views

Does playing music during sleep actually suppress rather than rouse the brain?

I've long been interested in the effect of music/sound on dreaming, and even built 2 apps that play music during REM period. Now I'm looking at this article about FMRI studies of a sleeping brain, and ...
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0answers
36 views

Is there a homeostatic setpoint for number of hours of sleep required by a human?

I've heard this TED.com talk about dieting and it mentions that there's a very definitive setpoint within the human brain about how much a human should weight. The speaker mentions that after as much ...
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4answers
40k 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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2answers
213 views

Do humans have a “dominant” neurotransmitter system/sensitivity within their brain?

I've recently heard a podcast, in which Dr. Helen Fisher suggests that there are "4 broad personality types", and each one is associated with a particular neurotransmitter: The corresponding ...
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2answers
1k views

Are humans an eusocial species?

In the evolution of sociality among animals, different degrees are acknowledged. Some species present overlapping generations, some division of labor, and the minority present reproductive division. ...
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1answer
66 views

Gradual slowing breath, its effect on health

I've written a computer program which beeps, then beeps after 10 sec, then beeps after 11 sec, then beeps after 12 sec, etc. I tried the following "experiment" on myself: do only one breath between ...
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1answer
59 views

What is the impact of prolonged electromagnetic exposure on human health?

What are the health effects of being exposed to a very strong electromagnetic field caused by two resonating superconductive coils (not static magnets) for a period of years?
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1answer
94 views

How does a smoker's pleasure work?

I smoke. For some reason, I've always had this idea that the pleasure of smoking works more or less like this: from the lungs, the nicotine reaches the blood, with which it travels to the brain, and ...
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4answers
47k 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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2answers
226 views

Rh factor and dominance of gene

"Formation of Rh antigen is controlled by dominant gene(R) and its absence by recipient gene(r).People having this antigen with genotype (RR or Rr) are called Rh positive and those whose blood ...
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1answer
171 views

Determining a patients biological age?

I am looking for an algorithm that shows the exact coefficients some variables that have on a hospital patient's chronological age versus their biological age. I understand a lot of the variables ...
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1answer
74 views

How good is information transfer between the hemispheres of the brain?

I sometimes listen to lectures on my phone using ear buds, but occasionally with only one ear bud in. Is the other half of my brain losing out on any aspect of the lecture? Just how good is the corpus ...
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4answers
185 views

Significance of having goosebumps?

What help does goosebumps do to us? I don't think it helps us noticeably when we are scared or shivering.
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5answers
9k views

Origin, or source, of rhesus negative in human blood

This is my first post here, so please be gentle. I recently learned that I have Rh- blood (I'm A-), and was idly looking into blood types on Wikipedia. I was surprised to find that relatively few ...
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0answers
36 views

How to predict the position of the femoral head center given surface anthropometric data?

Given surface measurements such as hip breadth and hip depth, how would you predict the location of the femoral head center?