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
98 views

What is the difference between a Human Being, Homo Sapiens and a Neanderthal?

I know that the Neanderthal's are a branch of the Human Being but how do all three relate to each other or more specifically what is the difference?
1
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0answers
59 views

Why are sarcomas rare compared to carcinomas?

A sarcoma (from the Greek σάρξ sarx meaning "flesh") is a cancer that arises from transformed cells of mesenchymal origin. Thus, malignant tumors made of cancellous bone, cartilage, fat, muscle, ...
7
votes
1answer
9k views

How much gas is exchanged in one human breath?

When we breathe, our lungs absorb a portion of the oxygen in the air, and replace it with some amount of carbon dioxide and water vapor. Typically, how much $O_2$ (in grams, milliliters, or moles for ...
-2
votes
2answers
53 views

Can all elements be found in our body? [closed]

There are many Natural occurring atomic elements. Can they all be found in the human body?
1
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2answers
852 views

What would happen if a person had the right side of their body totally removed (including the brain)? [closed]

What would happen (in reality or theoretically) if the entire right side of a human's body was removed? Could they live (aside from all the probable infections and such)? I would guess that humans ...
2
votes
0answers
50 views

Why do people tend to stand on one leg? [closed]

I know for a fact, by observing people and from own experience (you can try it yourself while standing, but not too consciously and in a loose way) that they (like birds), while standing, tend to do ...
4
votes
1answer
193 views
1
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2answers
15 views

Do Class A biosolids count as organic fertiliser?

Does Human Waste, which has been treated at least twice to remove pathogens & remove stink, still count as organic despite it passing the EPA's class A standard? If so, does this mean that none-...
0
votes
1answer
23 views

Cell division - meiosis

Really confused. How many chromosomes pairs do humans have in their sex cells? How many single chromosomes do humans have in their sex cells?
1
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0answers
13 views

Why human hair is losing its color over time? [duplicate]

Human hair is losing its color over time, that's a known fact. I would like to know why, meaning what biological processes are involved in this? Also, is it part of the DNA somehow, i.e. the exact ...
0
votes
0answers
13 views

Is salivation decrease during sleep beneficial?

Papers [1, 2, 3] tell that a salivation decrease is not only unpleasant, but harmful for dental health. What cause that decrease? What is the reason for it and do animals have it? I guess it's a ...
18
votes
2answers
13k views

Can one die from pain?

Is it possible that a human or any other creature can die from pain? I googled and found different answers. Some articles say Yes while others say No.
9
votes
2answers
2k views

Why do people feel pleasure when using roller coasters / centrifuges?

The feeling when using an amusement park unit is usually a pleasure. Why is it not a pain instead? Are there advantages, from an evolutionary point of view, in loving this potentially dangerous ...
2
votes
1answer
29 views

Do we know a complete list of nutrients that humans must ingest to live?

When the people who are making "nutritionally complete" foods like Soylent are developing their product, how do they know that they've covered all their bases? You need to have protein, carbohydrates, ...
12
votes
3answers
125 views

How does the brain immediately know when one's thirst has been quenched?

The question struck me the other day when I drank a glass of water. I understand that there are at least two conditions under which the brain signals thirst: extracellular thirst, when there's not ...
1
vote
0answers
52 views

Why do some men have patchy beards?

Why do some men have patchy beards? Or more specifically, why would some hair follicles lack sufficient 5-alpha reductase while others nearby don't when their genetic code is identical and they are ...
1
vote
0answers
26 views

Number of pair of chromosomes in sex cells of human [closed]

Just wondering how many pair of chromosomes in sex cells of human? How many single chromosomes in sex cells of human? Thanks for your help! It is said the chromosomes in sex cells are haploid?
9
votes
1answer
14k views

Name (and meaning of the absence) of the white semicircle at the base of the fingernail?

At the base of fingernail, there is a white semicircle (see on the first picture). But sometimes there isn't one. My questions are: what is this white semicircle on the fingernail, and what causes ...
0
votes
0answers
33 views

If your atlas is out of alignment, will the rest of your spine be out as well?

I just found out about this association called Nucca. Basically, they are a chiropractic association - their whole idea is that if your atlas is out of alignment, then the rest of your spine is also ...
1
vote
2answers
529 views

Can excessive carbonated drink consumption lead to elevated red blood cell levels?

I've recently had a blood test and the results displayed elevated levels of erythrocytes as well as hemoglobin. (As a result my hematocrit levels were also above average) At my workplace there is a ...
0
votes
0answers
22 views

peritoneal dialysis Vs Hemodialysis?

Their are basically two types of dialysis: 1.peritoneal dialysis 2.hemodialysis, My Question is Why the peritoneal dialysis needs to be carried out on everyday BUT hemodialysis is carried out on only ...
0
votes
0answers
10 views

Is there any range for Aortic Valve Gradient?

I understand aortic valve gradient is pressure on the value (measured in mmHg). What I would like to know is if there has been any research that identified a minimum and maximum pressure value as the ...
2
votes
1answer
1k views

Why does air from the nasal cavity not go into the oesophagus?

When we ingest food, the epiglottis covers the trachea and the uvula covers the nasal passage. But what happens when we breathe? Why does the air go into our trachea and not the oesophagus?
4
votes
1answer
309 views

How significant is the genetic component of homosexual behaviour?

From some basic googling, I found that nobody has ever proven that people are born gay and that environment plays a great part in homosexuality. I wish to know if there is a genetic component to ...
4
votes
1answer
1k 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, ...
0
votes
2answers
103 views

What makes something food?

From my (limited) understanding, animals get energy from food by breaking chemical bonds between molecules. There's a lot of water here [citation needed], so it seems like natural selection would ...
3
votes
1answer
80 views

Why cold water results in cough [closed]

I have a pretty simple question which always kept me intriguing since childhood and I couldn't find its precise answer yet. Why do we cough by cold water. Recently I had flu and found very strange ...
1
vote
0answers
47 views

What happens to the human brain when unconscious?

What part of the brain gets affected and does it harm the brain? Thank you I just needed some extra info for a video I'm making.
3
votes
1answer
1k views

What are hot spots on human body?

Recently I have just discovered that a certain amount of the mobile phone frequency can be absorbed by human tissues. For example, this is the SAR info of iPhone 4s: Head: 1.180 W/kg 1 g Body: 0....
3
votes
0answers
43 views

What happens to the brain during sleep versus unconsciousness?

How does being unconsciousness differ from being asleep and whether it causes breaks in consciousness?
3
votes
1answer
98 views

How two genomes adopt when cell goes to recipient's body from donor's body?

We often give blood to another following the blood giving compatibility chart. Heart transplant and similar transplants also brings one's cell to another's body. My curiosity is, when a cell goes to ...
6
votes
1answer
3k views

Why don't we have hair on palms?

We have hair all over the body except palms. What is the biological reason behind this? Thanks
5
votes
1answer
413 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 : ...
3
votes
2answers
172 views

Does sweat contain DNA information?

I was reading this article : Perspiration The first question which came to my mind after reading the composition of sweat was whether it contains any information about the DNA or not? I haven't had ...
3
votes
3answers
6k views

If the top epidermal layer is burned away, what is it replaced with?

If the squamous (top) layer of epidermis, or skin, is burned or damaged in another way, will it then be replaced by the next layer of below? Also, from where does the basal membrane originate? Does ...
0
votes
0answers
11 views

Cellular aspartate level?

I know that aspartate is a product of urea cycle, gluconeogenesis and oxaloacetate. In addition, there are dietary sources such as meat and vegetables. I would like to know what are the other factors ...
0
votes
0answers
62 views

Why is my right hand's thumb on the left side and my left hand's thumb on the right side?

My daughter just asked this question, and I could not provide a thorough answer. My first speculation is that it allows one to manipulate an object using one' both hands simultaneously (if the thumbs ...
5
votes
1answer
2k views

What does vitamin B6 and B12 absorption depend upon?

I'm looking at my question about homocysteine metabolism and am doing a followup inquiry into vitamins B6(Pyroxidine) and B12(Cyanocobalamin). I've found this interesting bit about vitamin B12 and am ...
-1
votes
1answer
81 views

Is it possible to grow a fertilized human egg entirely outside the woman's womb?

Many science-fiction movies show the possibility of growing a newly fertilized human egg entirely outside the womb of the woman. This means that you have to create the exact circumstances for the ...
8
votes
2answers
268 views

Are unilaterally deaf people able to determine where sound comes from?

My question is on people deafened in one ear, but normal hearing in the other. Time and level differences between the two ears are only part of how the human body can localize the source of the sound....
14
votes
1answer
20k views

What is the composition of human feces?

Are there any studies or general information on the composition of human feces? I'd specifically like to know the percentage of carbohydrates and amino acids relative to the amount that was ingested ...
0
votes
2answers
78 views

What physical traits are derived from the Neanderthal DNA in human DNA?

Some researches had found that Human DNA has a bit of Neanderthal DNA. So they suggested there would have been crossing between Homo sapiens and Neanderthals. Now the Neanderthal looked a bit ...
1
vote
2answers
71 views

Does night sleep provide more energy-regain than sleep during the day? [closed]

After reading this, I know that sleeping is an universal function, and that basically everything with a brain has the need to sleep. However, I am still confused to what extent it is necessary to ...
14
votes
1answer
956 views

I don't want to know what bacteria is called but if the bacteria from unborn babies have benifits on health? [duplicate]

This question is not the same as the duplicate. I was told that when babies are born they are born with bacteria in their stomach. When a child takes antibiotics are there unique bacteria destroyed ...
0
votes
2answers
87 views

Use of sunlight in biological processes

Sunlight is used by green plants in photosynthesis, but it is also used by animals in the synthesis of Vitamin D. Are there any similarities between the two processes and how is the light energy ...
1
vote
0answers
22 views

How much yogurt would one have to consume to have a noticeable effect on neurotransmitters [closed]

I read several recent articles that proposed a link between bacteria in our gut and neurotransmitters in our brain. For instance http://www.ncbi.nlm.nih.gov/m/pubmed/24997036/ I am curious how much ...
13
votes
3answers
477 views

How does a person get AIDS?

I am inquisitive to know about how a person contracts AIDS. Among the common masses it's still the belief that having sex with multiple partners causes the disease but that is not the case when read ...
1
vote
0answers
24 views

How do I “reinoculate” a petri dish with new bacteria?

Hypothetical question, intended to find a general procedure rather than case-specific recommendations: I have a petri dish full of growth medium with a large population of gram-negative, anaerobic ...
1
vote
0answers
54 views

Why is a wound much more painful when damp?

Why is a wound much more painful when damp? This is a very strange phenomenon. For example: I have a little wound, not painful at all. But, when it is just damp, it is much painful.
5
votes
1answer
138 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 ...