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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34 views

Does a pregnant female body treat the fetus based on gender?

I have seen on a youtube video that the female body produces antigenes and antibodies when she is pregnant with a boy. But this behaviour is not produced when she is pregnant with a girl. These means ...
6
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1answer
774 views

Warm water bath [closed]

Why is it advised to take bath in warm water when we are sick?I know that as homeotherms we need to generate metabolic heat to adapt to the environment temperature.But what is the mechanism by which ...
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0answers
19 views

Safety of cobalt-chromium and nickel-chromium dental implants

How safe are cobalt-chromium and nickel-chromium alloys used in dental implants (porcelain fused metal)? IARC groups nickel and cobalt metals in group 2B and chromium in group 3 (hexavalent chromium ...
3
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1answer
424 views

Do humans have the hyaloid canal, after all?

Most Google Images results for "eye anatomy" are pictures of eyes that don't have the hyaloid canal while some do (proof). Do humans have it, after all, or not? :)
38
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4answers
17k views

Death because of distilled water consumption

One of my friends said that I would die if I drank distilled water (we were using it in a chemistry experiment) I gave it a go and surprisingly did not die. I did a bit of Googling and found this ...
2
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1answer
34 views

Kinesiology Tape Benefits

Recently, kinesiology tape has become popular, especially in CrossFit. I have also noted its' use in the NFL, and I want to say Tennis as well. What beneficial effects does this tape offer our bodies ...
2
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1answer
40 views

Does Spinning dancer has anything to do with your eyesight

I came across the spinning dancer as part of the brain test to determine left brain vs right brain dominance. I saw the dancer is turning clockwise. The other people around me saw it turning ...
6
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1answer
3k views

What is the normal duration of human sexual intercourse?

Wikipedia is saying: Men's typical ejaculatory latency is approximately 4–8 minutes How the researchers measured this? How did they know if the test subjects weren't suffering from premature ...
3
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1answer
34 views

Why is Psoriasis treated with Cortisone, when stress (which releases Cortisol) is known to aggravate the condition?

It is well known that stress isn't good for psoriasis , yet why do we treat the illness with Cortisone, a compound very similar to cortisol (and "has a similar name, genesis, and function", according ...
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2answers
166 views

Eating rarely but a lot, or often but little

I wonder if it matters if an average person eats the same amount of food distributed between a few (2-3) meals during the day, or constantly having small snacks. I'm interested in several aspects of ...
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2answers
54 views

Is the quality of sleep dependent on sleep duration?

I've been facing this lately, where I will wake up in the middle of the night after sleeping for perhaps 2-3 hours and be wide awake, but when I go back to sleep, I wake up more tired than before. ...
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1answer
29 views

What does it mean to have different “metabolism”?

We hear talk of different body types, and that it is more difficult for certain people to lose weight than others. On the other hand, when my physician recommends that I lose weight, they say that it ...
12
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1answer
2k views

What do you see when your eyes are closed?

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...
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1answer
22 views

What triggers the release of gonadotrophin-releasing hormone with the onset of puberty?

I am interested to know the process of development of puberty. During puberty, when boys/girls reache 12-14 (puberty) years of their age, their hypothalamus releases gonadotropin releasing hormone ...
3
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1answer
48 views

Did the Britons 100 years ago have different intestinal flora and fauna?

Note: this is not a question about history, but about human digestive system over time :) I know a lot of colleagues who traveled for business trips to India. All of them caught terrible diarrhea ...
1
vote
1answer
30 views

Evolutionary support for parenting book “The happiest baby on the block”

The book by Dr Harvey Karp (MD) The Happiest Baby on the Block proposes that the duration of human gestation has evolved as a tradeoff between cranial size and development of the infant. He ...
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0answers
39 views

force required to do damage to child's leg/feet in collision [closed]

I'm currently working on a toy robot for a student project. Part of this robot is the fact that it will be moving around quite fast. As such hitting the child can and most likely will happen. As such ...
4
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2answers
71 views

What is MHC haplotype?

What is MHC haplotype? I did check out the wiki article, but did not understand. (I have not studied biology since last 8 years and now I am going through it because I need it for my research. So if ...
3
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2answers
58 views

Is it possible to calculate the energy required to speak a word?

I was discussing with a colleague whether speaking would require more energy than communicating via instant message (GTalk, etc..). If this is possible, then I'm particularly interested in whether ...
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2answers
1k views

Why would taking antibiotics increase stamina and energy?

I often hear that people who are taking antibiotics experience wild fluctuations between feeling full of energy and completely alert but soon after feeling impossibly fatigued and sick. Does this ...
2
votes
1answer
25 views

Difference between sequential and conformational epitope

Is the difference only in its structure? Like conformational epitope has 3D structure while sequential has a linear structure?(I have not studied biology since last 8 years and now I am going through ...
4
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1answer
99 views

Counterintuitive action of Vitamin D?

Vitamin D acts in a way which to me is counterintuitive. It functionally supplemets Parathormone. It in the intestinal tract steps up calcium absorption by altering nuclear gene expression and also ...
3
votes
1answer
120 views

How does Humira work when injected into patients with rheumatoid arthritis?

OK, I have rheumatoid arthritis and I've been injecting Humira 2 times a month for the last 8 months. As far as I know rheumatoid arthritis is simply an immune system disorder which makes the immune ...
4
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2answers
155 views

Where do the 31 spinal nerves start/meet?

Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that? Nominally, the beginning of ...
4
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1answer
60 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
111
votes
4answers
12k views

Why do I only breathe out of one nostril?

I was just sitting with my hand next to my nose and I realized that air was only coming out of the right nostril. Why is that? I would think I would use both, it seems much more efficient. Have I ...
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1answer
8k 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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3answers
3k views

What actually happens when my leg 'falls asleep'?

Most people have experienced the temporary loss of feeling and tingling in their leg resulting from sitting in an abnormal position for a short while. Usually you get a loss of feeling in your leg ...
3
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1answer
172 views

Why do I breathe out of BOTH nostrils?

After reading the question why do I only breathe out of one nostril I realized that breathing out of both isn't common. I have always breathed out of both, and when I get a stuffy nose, or a runny ...
4
votes
1answer
50 views

Oxidation means inflamation?

All right, I was reading article on nutrition, that focussed on content analysis of pastry-like food product for kids. I have to say that I am not sure this article would pass the imaginary smell ...
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0answers
41 views

Highest Pressure Human Body Can Survive In?

One design for underwater human inhabited environments is to have equal pressure between the surrounding water and the submerged habitat, thus allowing a section of the floor to be open to the water ...
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1answer
54 views

What is the use of shampoo; is it for the hair or for the scalp?

Apologies for the confusing question; I did not know how to better ask it. I was doing a search on wikipedia when I found this statement. Wikipedia's entry on hair states; "The hair that is ...
14
votes
2answers
5k views

Why doesn't water enter my body through my anus or genitals when swimming?

So when we swim, we can make water not enter through our nose and mouth, simply by holding our breath. However, the mouth and the nose aren't the only cavities. What about the anus and the genitals? ...
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2answers
4k views

Why do we sweat after drinking water and running?

Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?
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2answers
1k views

What would happen if one eats silica gel?

What happens if one actually does go about eating the beads in those "do-not-eat" packets?
6
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1answer
837 views

Chest muscle and female breast size

Do female chest size have anything to do with muscle? I know many female athlete and their average breast size is much bigger than normal female that does not tend to play sports. Do this have any ...
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0answers
12 views

Stress-responding enhancer?

I wonder if anyone knows a well characterized human enhancer which has been shown increased activity (in e.g. reporter assays) under stressed conditions, such as DNA damage, hypoxia, ...
3
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1answer
129 views

Why do we absorb vitamins better from whole foods than from pills?

We can't rely on pills to provide us our nutrients because we don't absorb the nutrients from the pills as effectively. Presumably this is because pills are lacking components that are required for ...
3
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1answer
188 views

Why are people tired after surgery?

I had surgery when woke up I felt like I only had 20% energy & felt extremely tired. Is this a common sensation? Why do people feel so tired after surgery?
3
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1answer
82 views

Are there any situations in which phenylephrine is preferred to pseudoephedrine?

In the mid 2000s in the US, due to issues of drug enforcement, pseudoephedrine containing medications were brought behind the pharmacy counter and in most cases require ID, and phenylephrine was ...
4
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1answer
113 views

Getting goosebumps at will

I can get goosebumps at will, regardless of the environment. Its mostly visible on my arms, and I can feel it on my head. It requires some level of concentration to achieve this. My questions are : ...
22
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1answer
12k views

How does laughing gas (N2O) work?

Laughing gas (N2O), well, makes people laugh. How does just a gas make us do that, there has to be some hormones at work... So, I wanted to know how this works? What is the mechanism?
7
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2answers
131 views

What causes skewed lanes in a DNA gel electrophoresis experiment?

In gel electrophoresis, what causes effects like these (see collumn 11 in the first one, an collumn 6 in the second). ? (These images were samples that I took from an online activity we did for ...
2
votes
1answer
98 views

Are retroviruses cytotoxic?

There are typically hundreds of retroviruses found in healthy human beings. Are retroviruses then cytotoxic? (In other words, are they able to kill or damage other cells).
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2answers
60 views

Why are human children more likely to get lice (nits) than adults?

By my own experience, lice seems to be prevalent in the hair of human children, but not in adults. My question is Why are human children more likely to get lice than adults? Assumptions: Can be ...
3
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0answers
66 views

What is the main challenge in creating a chemical male contraceptive?

More than 50 years after hormonal contraception for women was invented, a contraceptive pill for males is still not available. With the obvious major biological differences in mind, why does it appear ...
2
votes
2answers
46 views

What is a membrane potential?

I know this may be silly, but I am confused to what a membrane potential actually is. I understand that at resting membrane potential is -70- -80 mV. But what does that exactly mean and how does this ...
10
votes
2answers
27k views

How many human cells are there in our body, on average?

How many human cells are there in our body, on average? Wikipedia says 1013: Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in ...
2
votes
2answers
537 views

What happens if a person has the right side of the body totally removed (including the brain)? [closed]

I guess humans could live without just the right lobe of the liver or the right brain. Could a person without the whole right side of body survive? The left brain controls the right side of the ...
17
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2answers
2k views

Why was disease transfer to the Americas one-way?

It is well known that the European colonists brought many infectious diseases to the Americas, and that these had a deadly effect on the native populations, because they had no immunity to them. Were ...