This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

learn more… | top users | synonyms

5
votes
1answer
95 views

Where in the world does blue eyed whites originate from?

I know that there were no blue eyed people until ~6000 years ago due to a mutation and all blue eyed people have a single common anchestor. But where in the world does it originate? I assume it ...
1
vote
0answers
24 views

What are the molecular/cellular basis of pruritus ?

Could someone please explain the cells and molecules involved in the clinical phenomenon of pruritus ? I'm interested in a general view about the subject, but detailed answers will be appreciated. ...
16
votes
2answers
13k views

Why do people have antibodies against other blood types?

The ABO blood type divides each blood type according to whether they have the "A" and "B" antigen(s) (AB has both, O has none). People also have antibodies against the antigens they don't have (AB has ...
3
votes
4answers
111 views

Can general soap kill bacteria?

I have read that general soap can kill bacteria by opening holes in the bacterial membrane. http://questions.sci-toys.com/node/90 However, I found some articles as well saying that it cannot. ...
1
vote
1answer
71 views

Transmission of HIV from Mother-to-Child Through Breastfeeding

If a mother is HIV+ and was on medications which would help her deliver a HIV negative baby, can the baby contract the HIV through her breast milk?
3
votes
1answer
74 views

What causes the pain when a bone fracture is healing?

Why does a fracture still hurts when it is healing? I understand the pain at the beginning - the bone is not in its place, there is a pressure against the nerves, also the swelling pushes the nerves ...
4
votes
2answers
498 views

Does frequency of eye blinking reveal anything about human biology/nervous system?

I'm looking at an output of a single dry sensor EEG headband with the sensor positioned above left eye. As a side effect of it's placement, the device picks up eye blinks, and some eye motion as ...
2
votes
2answers
133 views

What makes diffculty to make a human bio-tooth compare to a mouse's? [closed]

Some time ago I read a news article that said a bio-engineered tooth based on a mouse's would be available around 2015. There was some research about it at King's College in the UK, and many other ...
2
votes
3answers
262 views

What is the biological significance of finding palindromes in DNA sequence?

I found a function called palindromes in Matlab that finds palindromes from DNA sequence. Now what is the biological intention behind incorporating this function? What the biological significance of ...
7
votes
2answers
341 views

Is warmth/temperature sensed linearly or on a different scale?

I understand that the atmospheric temperature is sensed relative to external body temperature. However, is the sensation of warmth registered linearly, or is it on a logarithmic scale, similar to ...
0
votes
1answer
61 views

What if there are no bacteria such as Streptococcus mutans

If someone removed all bacteria such Streptococcus mutans in her mouth by starving long time, or by some chemical method, would she never have such bacteria? In my thought, because S.mutans only ...
1
vote
0answers
80 views

Why does the ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process?

Why does the human ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process??Please help me with it.
8
votes
1answer
92 views

What happens to the food you accidentally aspire?

I'm well aware of health effects of aspiration of solid food and liquids, but I'm interested on what is the reaction of the body on the biological level to the strange body on our lungs. I ask this ...
33
votes
1answer
5k views

What causes morning wood?

Sometimes men wake up with an erection in the morning. Why does this happen?
0
votes
1answer
53 views

Are progenies factually half-clones of the parents?

Given that a "clone" (if anything, in the context of human cloning) is taken to be, as far as I have understood, a specimen possessing the same genome as his "father/mother", aren't all "non-cloned" ...
0
votes
0answers
12 views

Why do I wake up with morning wood? [duplicate]

According to this answer on a question about the brain, the answer implies that based on certain activities the human body is undergoing, the brain then diverts the appropriate needed resources to ...
6
votes
1answer
75 views

Do blood glucose “spikes” contribute to insulin resistance, or is prolonged elevation required?

There's increasing public discussion about the health risks of chronic insulin resistance* (IR). In many cases there's a focus on high glycemic index foods that "spike" your blood sugar, which implies ...
2
votes
1answer
191 views

What is the global average BMI?

I have been looking for hours trying to find this number, and can't seem to get a straight answer. I've seen some studies that calculate the change in BMI, but for some reason they don't give you the ...
0
votes
2answers
41 views

Rampant low Vitamin D

Why have people inadequate vitamin D status? Is it just (the lack of) sun exposure, or is it related to hormone and thyroid function?
2
votes
1answer
29 views

Why does mud therapy work by some pain related diseases?

Apparently, some users here agree there is no ion exchange through the skin. Mud therapy has some therapeutic effect for pain related diseases. As an anecdotal example, I experienced pain relief by ...
0
votes
0answers
45 views

Are lines (wrinkles) on the human forehead skin related to science of (often worried) thinking?

It is the common observation that when we tend to think about anything, most often, we tend to make the conformation of raising the skin of forehead; from my observation this is the most common ...
0
votes
1answer
36 views

How can rapid growth cancer get nutrients in vivo?

When I was little, before I get into biological studying, I read a news talking about cancer would be totally cured after decades. I still remember that researchers had a theory to claim if they could ...
11
votes
2answers
4k views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
2
votes
1answer
6k views

Are Asian people genetically programmed to be shorter than Europeans?

People in different countries have different average heights. For example, Wikipedia's article on human height states that Australian men have an average height of 177.8 cm, and Australian women 163.8 ...
1
vote
1answer
59 views

Is it possible for a person to eat so many carrots that one turns orange?

I once read that Jerry Rubin (a famous 1960s activist) ate so many carrots that he turned orange. (This was in the East Bay Express, around twenty years ago.) I assumed it could be true, though he ...
0
votes
1answer
108 views

Why don't we have two hearts? [duplicate]

The human body is amazing. But there seems to be some evolutionary changes that appear to not make sense regarding redundancy. While not necessarily the primary reason for their existence, the human ...
10
votes
4answers
13k 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 ...
24
votes
3answers
51k views

Why do mammalian red blood cells lack a nucleus?

How did the red blood cell in humans get to lose its nucleus (and other organelles)? Does the bone marrow just not put the nucleus in, or is it stripped out at some stage in the construction of the ...
0
votes
2answers
58 views

Can we change one's genome into the genome of somebody else

If I (grown-up individual and not just an egg after fertilization) wanted your exact genome, would we be able with today's technology to change my genome into yours?
3
votes
3answers
30k 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 ...
15
votes
2answers
804 views

Why does mouldy food make you sick?

Bread gets mouldy pretty quickly, and my parents (both of whom are nurses) throw out a loaf of bread after a spot of mould is seen (because "if you can see one spot, it means the whole thing is ...
0
votes
0answers
14 views

Growth of Yeast in Different pH Mediums

Will yeast grow better in acidic, basic or neutral mediums? Why? Will the medium affect the growth of yeast? (Yeast cell membrane is semi-permeable).
1
vote
2answers
86 views

Are oxygen and carbon dioxide simultaneously present in red blood cells during gas exchange?

From my understanding, the process that displaces the carbon dioxide and oxygen in our erythrocytes and lungs is diffusion. I've been taught that diffusion is the net movement of particles from a ...
3
votes
2answers
123 views

Does melanin protect humans from gamma radiation?

It is known that radiotrophic fungi use melanin to make use of gamma radiation. It is also known that melanin protects human skin from UV radiation. Thus I wonder whether melanin protects humans from ...
0
votes
0answers
18 views

Electrically facilitated active transport across a membrane

I'm trying to go back to school to do a PhD in control theory, specifically concerned with control of glucose. The glucose system can be controlled using two chemicals: insulin and glucagon. I was ...
21
votes
5answers
9k views

Why do the two hemispheres of the brain control the opposite sides of the body?

Why does the left hemisphere control the right and the right hemisphere control the left? I googled it but didn't find a good answer regarding this. Could someone explain? Does this adaptation help ...
1
vote
3answers
584 views

Do we consume dna, proteins of other organisms?

When we eat raw meat, e.g. chicken or fish, we are actually consuming the DNA, proteins etc. which are present in their cells. Wouldn't this affect our cell functions as this DNA might enter our ...
11
votes
3answers
47k views

What is the healing process of mouth wounds?

When we have an external wound, blood generally tends to clot there, forming a layer of solid scab. Yesterday, while brushing my teeth, I somehow hurt my gums and it got all bloody. However, it did ...
13
votes
2answers
4k views

Why do we urinate more when we are nervous?

This question is a result of my personal experience... But I guess that is common for many of us. My school timing is 8:00 am to 1:30 pm (usually). During normal school days I typically urinate one ...
1
vote
1answer
55 views

Human population growth - where can I find the data?

Out of curiosity, I'd like play around with data of human global demography. Where can I find data that describe the "per region (per continent for example) population size" versus time since the ...
8
votes
1answer
2k views

Can females be recreated from male DNA?

A chromosomal male is XY and a chromosomal female is XX. Now imagine if, one day, this world has only males - is it possible to "recreate" a female by using two X chromosomes from two different males? ...
14
votes
4answers
9k views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
6
votes
4answers
281 views

Can children restore brain cells?

By "children" I mean young people at the age of 10 or lower. I know that the adult brain cannot restore brain cells, but what about children? I mean, the brain must develop from a few cells to a 90 ...
5
votes
1answer
778 views

Why do we get 'bags under our eyes'?

Why do these circles form around the eyes if somebody is tired? And why does fatigue express itself around the eyes this way? Can I get eye bags very quickly in another way? ...
0
votes
1answer
170 views

What is the point of a runny nose during a cold?

What is the biological purpose of having a runny nose during a cold? Note, this is a different question than "What causes a runny nose" and other similar questions. Those question are about the ...
10
votes
3answers
4k views

Is nicotine toxic to humans?

More specifically, is nicotine in the concentrations that smokers receive when smoking cigarettes toxic? I know that in great enough concentrations it can be toxic (but then, so can just about ...
4
votes
2answers
212 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 ...
1
vote
0answers
34 views

Birth control hormones in the water? Or not?

This prior question talks about natural estrogen (TL;DR: Months to years): How quickly do estrogens break down in the environment? Ref: http://dx.doi.org/10.1038/485441a A lot of media has said, ...
6
votes
2answers
139 views

Are there nerves in the umbilical cord?

I have always imagined that cutting the umbilical cord after birth might be painful. But I have always been confused about who would feel the pain and why. It occurred to me that the mother or the ...
8
votes
3answers
360 views

Do spinal cord reflexes (such as the knee-jerk reflex) continue to function under general anaesthesia?

The knee-jerk reflex (patellar reflex) is an example of a stretch reflex (myotatic reflex). Stretch reflexes are monosynaptic reflexes happening in the spinal cord without involvement of the brain. ...