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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3
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1answer
52 views

How is Microenvironment strictly defined?

I started to think this definition of Wikipedia: Microenvironment (biology), a small or relatively small usually distinctly specialized and effectively isolated biophysical environment (as of ...
8
votes
1answer
138 views

Can a human cell live indefinetely in a controlled environment?

How long can a human cell live in a controlled environment, given all necessary nutrients, temperatures, mechanisms for waste removal, and other requirements are provided for? Put differently: Can a ...
4
votes
1answer
91 views

Are all functions of a human cell known? [closed]

Please bear with me as I'm intruding into your world from a computer science background. In programming, once you have created a program, you know all functions of that program. Thus, 100% knowledge ...
3
votes
1answer
2k views

Do you produce more sperm after 1 week of abstinence vs 1 year of abstinence

Question: I was wondering if the amount of sperm increase with the amount of abstinence? Side questions: Is their a max amount of sperm? What happens with the excess amount?
0
votes
1answer
48 views

Is there any research paper which identifies left and right brained behavior?

There are many web puzzle to identify, but does it really have any scientific proof? something like - http://braintest.sommer-sommer.com/en/ any logic behind it?
3
votes
1answer
232 views

Is the activity of enzymes in the human body affected by the outer temperature?

I have to do a research about the enzymes in the human body and the things that affect them. I know that the body temperature affects the activity of enzyemes but I'd like to know if the outer ...
2
votes
1answer
41 views

Help me understand my membrane potential assignment

Epithelial with the ability to transport NaCl is bathed in an isotonic salt solution with these values (in mM): 136 Na, 6 K, 140 Cl. The intracellular concentrations are: 45 Na, 100 K, 13 Cl. The ...
2
votes
1answer
50 views

Like size and colour constancy, why does the brain not maintain focus constancy?

I have progressive myopia. I grew up with perfectly normal eyes but slowly started getting myopic. The thing is, my brain knows (or should know) what the world looks like -- it knows that far away ...
1
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2answers
68 views

Can Hepatitis be caused by Bacteria?

There are many information about viral hepatitis. But it is interesting for me, can bacteria cause the hepatitis too?
2
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1answer
156 views

What are the disadvantages of forbidding flights to and from the African Ebola region?

After looking through the available Stack Exchange sites, this one seems to come closest to the appropriate place to ask... Popular opinion, including my own, is that banning flights to and from the ...
5
votes
2answers
160 views

Problems understanding membrane potential

I understand that membrane potential is the difference of the extracellular and intracellular ionic charges, due to their concentrations. We say that the extracellular space has a charge of 0 and then ...
1
vote
1answer
87 views

Understanding intra and extracelullar concentrations (membrane potential)

I have 4 question (not homework) What happens to the cells membrane potential if: a) Na+ outside rises by 40mM b) K+ inside rises by 10mM c) K+ outside rises by 10mM d) A- (impermeable ion) ...
9
votes
1answer
247 views

Why can you not tickle yourself?

It's the age old question, why can't we tickle ourselves? If you rub your fingers along your skin, sure there's sensation but you don't break down into a laughing fit (at least I don't :P), if someone ...
2
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1answer
52 views

Why can't we smell our own bad breath? [closed]

Why can't we smell our own bad breath. Is there any way we can do that?
2
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2answers
162 views

Is there a known glucosepane cross-link breaker?

I read the following on wikipedia: There is, however, no agent known that can break down the most common AGE, glucosepane, which appears 10 to 1,000 times more common in human tissue than any ...
1
vote
1answer
857 views

Why is it better to drink room temperature water instead of cold water? [closed]

My teacher told me that drinking water that is room temperature is better for you then drinking cold water, but she did not tell me why that is. I want to know because I often drink cold water (with ...
5
votes
1answer
83 views

Are some facial features more important than others in human facial recognition?

I'm often surprised by the human ability to correctly identify other individuals despite significant modifications due to ageing, hairstyle, injury, etc. But, sometimes the addition of a beard and a ...
4
votes
1answer
46 views

How can ingesting a prion “infect” someone?

That's something that's been bugging me for a while... Our gastrointestinal tract produces proteases that degrade proteins. Prions are proteins. Shouldn't they be broken by proteases? Also, how can ...
1
vote
0answers
136 views

Can sealed epiphyseal growth plates theoretically be restored via epigenetic or genetic methods?

I know that epiphyseal growth plates seal up once people become young adults and that it is currently impossible to restore them to actively produce new bone growth but, is it theoretically possible ...
1
vote
0answers
43 views

Is Canine teeth enough evidence to prove that one is a Carnivore?

This question does not assume that we are meant to be carnivores in the first place; In fact I have no idea to which category we belong to anyway! There are several posts online indicating that ...
4
votes
3answers
4k views

Is it possible for a child to grow taller than their tallest parent?

I have heard that offspring can't grow taller than either of their parents but I've also heard that sometimes some gene activation can skip generations. Is it possible for a child to grow taller than ...
0
votes
1answer
62 views

Is the innate immune system capable of identifying all foreign antigens?

I've been studying immunology on my own lately and I would like to know if the macrophages and the other components of the innate immune system are capable of identifying all foreign antigens. As far ...
0
votes
0answers
43 views

Do animals have social status as humans in our society?

As our society and it's functioning is closely related to the ones of animals, one question arises: Do animals in nature have social status as humans? People often display it publicly, by buying nice ...
3
votes
1answer
631 views

How does electrolarynx work?

I have heard that this is an effective replacement for patients who have a dysfunctional larynx, partly due to cancer. I am curious to know the inner working of this device and why such a robotic ...
0
votes
1answer
34 views

Help me understand how the thyroid secretes

Please have a look at this close up light microscopic image of a thyroid gland: So I'm guessing the cubic epithelial cells surrounding this big red pulp are the secreting cells...? If so, is the ...
7
votes
4answers
230 views

How does an embryo know where to grow limbs etc

For example you have a cell or already a bunch of cells. Those cell(s) divide and after several week you have a grown organism, for example a human with limbs, several different organs etc. However, ...
2
votes
0answers
134 views

How many proteins are synthesized in human body throughout life?

My idea to calculate this is: Define up to what age will do the calculation. (for instance 60) Determine how many cells born and died up to that point in life. (by type of cell) Determine how many ...
16
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1answer
136 views

What is the mechanism responsible for the periodicity of hiccups?

Hiccups (singultus) are caused by involuntary spasm of the intercostal muscles and diaphragm, producing a sudden inspiration with associated glottic closure. It seems the neurobiology of the reflex ...
3
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0answers
132 views

Which types of blood vessels can regenerate in humans/mammals?

Which types of blood vessels can regenerate in humans/mammals? From what I understand, arteries and arterioles can be created later in life, while this is not necessarily the case with veins. However ...
8
votes
1answer
824 views

Does a bigger breast give creamier milk?

It is fairly common for a woman to have one breast larger than the other. I have also heard that, for a breast feeding mother it is common for one of the breasts to yield a creamier milk whilst the ...
1
vote
0answers
55 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 ...
0
votes
1answer
87 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
votes
1answer
244 views

How are arms different than legs?

Ok, this is a bit of a tangent question, but it came up yesterday and I didn't know the answer: How are arms and legs defined physiologically? For example, we say humans have two arms and two legs, ...
3
votes
1answer
522 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? :)
6
votes
1answer
800 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 ...
2
votes
1answer
94 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 ...
3
votes
1answer
146 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 ...
3
votes
2answers
91 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 ...
2
votes
3answers
84 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. ...
19
votes
1answer
5k 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 ...
3
votes
1answer
68 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
73 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 ...
8
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2answers
4k views

Do biological facts determine when a human fetus is considered alive and human?

I often hear or read this statement: "It's not a human, it's a fetus." In other words, some think a fetus is non-human until a certain point. And another similar statement: "The fetus isn't ...
2
votes
0answers
56 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 ...
3
votes
2answers
181 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 ...
2
votes
1answer
405 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
votes
2answers
471 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 ...
2
votes
1answer
53 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 ...
4
votes
1answer
57 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 ...
4
votes
1answer
485 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 ...