Biology pertaining to humans
7
votes
2answers
147 views
Why are some menstrual cycles irregular?
A friend of mine asked me this today, and I didn't know. I remember studying the menstrual cycle a few years ago, but I can't remember the details (other than it was very hormone-related), and so I ...
0
votes
1answer
25 views
Ill effects of urea and NH3 on metabolism
What exactly does urea do that harms our body ? Does it interfere with our cellular processes or disturbs the colloidal onchotic pressure of our blood ?
I have heard that NH3 damages the brain . What ...
5
votes
1answer
62 views
What effect do oligosaccharides, like those found in legumes, have on the composition of intestinal flora in humans and if so how so?
I know that intestinal flora metabolising oligosaccharides, like those found in legumes, is the cause for the well known fact that legumes cause flatulence, but does an oligosaccharide-rich intestine ...
3
votes
2answers
119 views
Physiological indicators of happiness and well being
If I understand it correctly, levels of serotonin in the brain can indicate if a person is happy. What other physiological measures indicate happiness or well being for a humans?
I am looking for ...
3
votes
1answer
52 views
What nutrients can humans absorb in the mouth?
For instance, I realise being able to absorb simple sugars in the mouth is pivotal in the rapid action of oral glucose gel. Thus I was wondering what nutrients in general can be absorbed directly ...
0
votes
1answer
27 views
copper spiral birth control not toxic?
I Always thought that copper was toxic to the human body.
So how can it be safe to place a copper object (birth control spiral) into a uterus for a duration of 5 years?
5
votes
1answer
109 views
What could account for an apparent loss of mass at death?
An interesting tidbit floating around the internet these days is that Dr. Duncan MacDougall apparently weighed people shortly before and after death, and found an average of a 21 gram discrepancy, to ...
0
votes
0answers
16 views
Ideas for mobile apps focusing on community health and preventative care? [closed]
I am a software developer and would like to make some free apps to assist people with their healthcare, especially those who are underserved or typically are not involved in their healthcare. And I ...
2
votes
0answers
21 views
How to use mechanical microstrainer to extract tissue proteins from human?
Background:
There are many methods to extract proteins form human tissues out there. The majority of them use an extraction buffer containing variable concentrations of detergents and protease ...
11
votes
1answer
307 views
Are human bodies programmed to die?
Following from this question: What is the evolutionary advantage of death?:
Is there any evidence that human bodies have systemic self-destruction built into their developmental program? I'm not ...
2
votes
1answer
30 views
Why is the blood pressure in the superior vena cava during inhalation less than during the exhalation?
For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart ...
3
votes
1answer
50 views
Why does it hurt more when you touch a nerve directly?
I am not a biologist nor know much about biology (so please explain in layman's terms) however I have always been curious as to why this is.
What causes the difference in pain between touching an ...
1
vote
1answer
124 views
What would be the best design for spike-and-recovery and linearity-of-dilution validation experiments in one 96-well ELISA plate?
I have searched in the web for a detailed explanation of doing such validation experiment, but unfortunately couldn't find a satisfactory one. I came across the following sources:
Thermo ...
2
votes
1answer
29 views
Is RGB diode lighting okay for the eyes?
Is a light source giving off light composed of red, green and blue lights harmful to the eyes? Does it lack any important qualities that other artificial light sources, such incandescent lamps or ...
2
votes
1answer
70 views
Why does yawning impair hearing?
When I yawn I can't hear anything happening around me. I also feel some kind of muscles inside my head contract and hear a faint hum, but it is not loud enough to explain not hearing other sounds. I ...
4
votes
0answers
59 views
What is the evolutionary reason behind the fragility of teeth?
Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
1
vote
2answers
95 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 ...
2
votes
2answers
85 views
How long human can survive with just drinking water everyday
Can man can live without eating food just by drinking water.
How long human can survive with just drinking water everyday?
12
votes
1answer
3k 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 ...
5
votes
1answer
3k 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 ...
3
votes
2answers
124 views
Is it possible to correctly identify presence of Y chromosome with external physical test only?
I asked a question related to the third sex, and I came to know that its always possible to categorize a human to male or female with presence of Y chromosome.
Now, I have another question. Is there ...
2
votes
2answers
77 views
Can a new Y-chromosome be created?
The major gene of the Y-chromosome is SRY. Would it be possible to get the X-chromosome and add SRY to create a "fuller" Y-chromosome?
What advantage does the skinny Y-chromosome give an individual ...
1
vote
1answer
35 views
I'd like to know the name and a few details of a certain time-keeping structure in the human brain
I once heard of this structure on the Discovery Science channel and have since forgotten the name. The details I remember about it were that it is the central time-keeping device for the brain located ...
11
votes
4answers
1k views
Do white Australians have a distinct look?
Background
I've heard from many people working in tourism or similar industries that, white Australians can be recognized as Australian solely by their facial features. Being Australian myself I've ...
5
votes
1answer
48 views
Do lunar rhythms have impact on human biology, if so, how?
I'm approaching this question from the circadian rhythm perspective. A circadian rhythm is a 24 hour cycle. While doing research on deep sea circadian rhythms, I found this abstract which seemed to ...
0
votes
0answers
27 views
What processes are responsible for focusing on an image only seen by one of the eyes?
When a person is spying from around a corner with only one eye, it's rather easy to ignore the other eye's image, since it's probably much darker, because one usually spies around a corner standing ...
1
vote
2answers
73 views
What organs are absolutely needed by the human body?
The title is my question: what organs are absolutely needed (fatal if injured/removed) by the human body and perhaps animals in general?
I'm not asking which organs are mechanically replaceable, but ...
4
votes
1answer
63 views
Why does plucking nose hair cause tears in the eyes?
It's not a particularly sad or painful thing to pluck a few nose hairs, but it's common for the tear ducts to wet up when doing this.
I would like to know the physiological reason for the ...
2
votes
1answer
23 views
Is there a comprehensive list of human circadian-like processes, hormones or gene expressions?
I'm reading this article onblood sugar and circadian rhythms and the following question popped into my head: a lot of articles mention various diurnal or circadian rhythmicity of biological processes. ...
-4
votes
1answer
48 views
What are the long-term negative effects of going without water/food for a period of time [closed]
There are no good answers anywhere. so asking: this is not about days of survival without water. This is about long-term negative effects induced from not drinking water for at least the mentioned ...
0
votes
0answers
36 views
Size order of human organs
Wikipedia states that the liver is the largest internal organ in the human body.
How does it relate to the sizes of ex. the lungs and small intestines? I've been having this personal image for years ...
0
votes
1answer
32 views
Could a person become physically transgender through artificial means?
Let's say there's a girl who carries a few masculine traits not normal in most girls, such as a high level of testosterone; we know there are countless reasons why something like this could happen, ...
9
votes
1answer
102 views
What light intensity starts melatonin release in humans?
I'm interested in whether any studies have determined the intensity of light at eye level that starts melatonin release in humans.
I know that:
melatonin release is suppressed by blue light with ...
3
votes
1answer
45 views
Why it is so difficult to treat leukemia?
I want to ask what is the reason that T315I type CML leukemia is currently untreatable. I have read quite a few papers in this subject. Why the current genetic oriented engineering drugs failed to ...
9
votes
2answers
115 views
Does human digestive system benefit from eating same kind of food consistently?
Here's the reason why I'm asking: I've heard that it takes some time for pets(cats/dogs) to adjust to a different dry feed, where the new feed has to be mixed with the old one, slowly replacing the ...
1
vote
0answers
33 views
Why do ion concentrations change with different secretion rates in pancreatic juice?
Why is it that when secretory rate increases in the pancreas the concentration of chloride ions decreases, and the concentration of bicarbonate increases in the production of isotonic NaCl secretion?
...
2
votes
2answers
46 views
What mechanism suppresses melatonin release in humans?
I'm looking at melanopsin, a photo pigment in the human eye. One of its actions is to trigger suprachiasmatic nuclei SCN to suppress melatonin release. I'm interested in learning what is the exact ...
1
vote
0answers
64 views
How does geography affect morphological features of the human body
I've seen many times how a person born in one place, goes to another country for a long time, and then they start looking more like the people there, but I never found out how it works.
This report ...
1
vote
2answers
81 views
How to know if a woman is fertile without actually making her pregnant?
How to know if a human female is fertile (can give birth to child in future) without making her pregnant? Any signs, tests?
13
votes
4answers
655 views
Can two humans with 44 chromosomes produce viable offspring?
It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes.
One example is a male in China: the first article, the second article.
The other is a female in ...
9
votes
2answers
303 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 ...
1
vote
1answer
41 views
Whence fecal E. coli (et al.) if swallowing it is dangerous?
I don't know much about medicine, and I know even less about microbiology, but I understand that there are organisms in the lower gastrointestinal tract (and in feces) of a human, like Escherichia ...
8
votes
2answers
216 views
Below which temperature human muscles don't work?
When one exposes theirs body parts to cold environment (especially foot and hands), they may be numb, with temporarily blocked both muscles.
What is typical body temperature below which human muscles ...
1
vote
0answers
35 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 ...
0
votes
1answer
14 views
Is there any relation between weight class and extreme lifting performance in O-lifting?
We usually thought that weightlifting is a tough game. It is only for great physique.
There are 6 man in history who lifted 3 times their body weight. Check here.
3 of them are Bantamweight(56kg), ...
0
votes
0answers
22 views
Perception of distant lights without glasses
I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's ...
0
votes
2answers
215 views
What part of food gives the blood red color?
Roughly, what I know is, when we eat food it goes into our: Stomach > Small Intestine > Large Intestine > Rectum. So, it just moves through a digestive pipe.
What I don't understand is, what part of ...
7
votes
2answers
116 views
During famine, does the human body do anything to prioritize which organs receive nutrients?
When food is scarce, the body slows its metabolism. Are there any other systems or processes that encourage prioritization of organs?
7
votes
1answer
95 views
How Antioxidants affects Human Metabolism?
I'd like to know how antioxidants affects the human metabolism and which ones are essential for metabolism processes.
6
votes
2answers
107 views
In humans what is the last metabolic process to cease after death?
After death which of our body's metabolic processes will continue functioning for the longest?
