Biology pertaining to humans
9
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1answer
131 views
In which order did the cells of the immune system evolve?
Thinking about how complex the interactions between different types of immune system cells (T-helpers, T-Killers, Phagocytes, B-Cells etc.) are, it's fascinating how they all combine to get the ...
2
votes
1answer
2k views
What is the functional difference between hemoglobin and ferritin?
I read that both hemoglobin and ferritin are for storing iron in the body. So, what is the difference between them in terms of storing/binding iron?
2
votes
2answers
70 views
E. coli, risk of infection?
There has been a warning about E. coli contaminated water in South Florida. Now I'm wondering are there empirical data or historic cases which show a correlation between E.coli levels in tap water and ...
1
vote
1answer
20 views
Can the excessive consumption of mineral water lead to kidney stones or other health issues?
I heard that drinking too much mineral (bottled) water could lead to problems such as kidney stones because of the high amount of minerals in it. Is it true? If so, what is considered to be excessive?
...
1
vote
3answers
40 views
Blood pressure during exercise
What happens to blood pressure when we exercise ? Does it increases , decreases or remains the same? If it does increases , why are blood pressure patients recommended to exercise ?
6
votes
1answer
2k views
Mitosis in human body
I've heard that stomach lining has the fastest reproducing cells and the brain has the slowest.
Where in the human body does mitosis occur and at what rates do these cell reproduce? Is there a chart ...
0
votes
0answers
44 views
Structure of adenoids
I am not sure this question belongs in biology, but I can't find a more suitable stack exchange site, feel free to delete it if this doesn't fit here.
Also, this question is going to be slightly ...
3
votes
1answer
96 views
Are there records of monozygotic twins in which one experiences androgen insensitivity syndrome
I have given my high school biology students the thought experiment of "What would happen if a researcher induced twinning of a female zygote and then replaced one of the X Chromosomes with a copy of ...
4
votes
1answer
69 views
How does skin healing work?
I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
4
votes
2answers
112 views
How does fever physically work?
What is the physical mechanism that causes temperature to rise during a fever? I know that somehow the hypothalamus "orders" to increase the standard body temperature regulation, and this should ...
19
votes
2answers
3k views
If a human takes antibiotics are all bacteria in the body killed?
From my basic understanding, antibiotics kill living things, bacteria for example.
Do the antibiotics consumed by a human-being distinguish between what they kill? Or do they just kill every bacteria ...
7
votes
1answer
100 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 ...
5
votes
1answer
66 views
Is human face more resistant to cold than other body parts?
Walking outside tonight in -15˚C I realized an interesting observation: While I felt cold on most part of my body, my face (although the only uncovered part) didn't really feel cold. It registered the ...
6
votes
1answer
92 views
Does muscle growth trigger angiogenesis?
So heavier people generally have more blood than lighter people (this is why heavier people generally need to take higher doses of medication for the same effect of medication). They also have more ...
2
votes
0answers
40 views
Movement of stem cells from mother to fetus
Recent results from J Lee Nelson and colleagues (Sci Am. 2008 Feb;298(2):64-71; available as full text through Google) show that cells from the mother were found in a person aged 46. Logically, these ...
1
vote
1answer
51 views
How do changes in temperature affect body weight in humans?
What would be effect on weight of individuals if we bring a fully adapted (to cold climate ) human individual and a fully adapted to very hot climate individual to a moderate climate region?
1
vote
0answers
23 views
What parts of the brain are involved in regulating blood pressure in mammals?
I'm reading this Wikipedia article on blood pressure and its regulation, and it mentions that medulla is involved. however, I vaguely remember reading another article on Wikipedia and it mentioned ...
-2
votes
1answer
72 views
Are we evolving to age slower, or to live longer aging at the same rate?
I wonder why most of us find senior people lovely and charming. Is it because to love grandpa and granny is vital to our survival as a species, in the same way as we love babies? If so, it would mean ...
0
votes
0answers
58 views
Do women feel pain the same exact way as men do?
Give the same stimulus and aside from cultural, nature vs. nurture debates, would pain be perceived equally between the sexes?
Do both sexes, at the level of the brain, feel the same median range of ...
9
votes
2answers
163 views
Does arterial blood always flow away from the heart?
Is there a negative net flow of blood in human arteries at any point of the cardiac cycle? I realise that blood flow can be turbulent, e.g. in the aorta or around stenotic arteries, but then the ...
1
vote
1answer
50 views
Can antibodies be formed against white blood cells after blood transfusion?
If antibodies are produced against other blood group's RBC , why can't antibodies form against WBC , of any blood group? ( even the same one , as MHC will be different in almost all individuals )
4
votes
1answer
96 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
59 views
Ammonia smell after physical exercise? What is the explanation?
After exercising vigorously one can sometimes smell ammonia and it feels like it's coming from within the nose actually. There is no indication that others can smell it when I do (i.e. seems to be ...
4
votes
1answer
1k views
What causes random long white body hairs?
I'm sure many of you have experienced this - you scratch your back or brush your hand over your arm and find a ridiculously long thin white hair, sometimes as long as 3 or 4 inches. I know a few ...
-2
votes
0answers
21 views
sebaceous cysts [closed]
How to get remove sebaceous cysts on testicles caused due to high testosterone production in body (possibly) ?
http://en.wikipedia.org/wiki/Sebaceous_cyst
1
vote
0answers
46 views
Would a spinal injury decrease human height?
A woman I know has been losing height at a rate of 10cm a year following a severe spinal injury. How is this possible? What kind of injury could cause such progressive loss of height? Could this be a ...
0
votes
0answers
15 views
Which hormones/ neurotransmitters are involved in human motivation?
I'm reading this Wikipedia article on motivation, and noticed that it does not have a section specifically related to hormones involved in "getting things done"
At the same time there is this ...
7
votes
1answer
161 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
33 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
73 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
138 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 ...
5
votes
1answer
62 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 ...
1
vote
1answer
37 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
174 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
17 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
24 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
331 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
54 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 ...
4
votes
1answer
65 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
152 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
32 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
90 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 ...
1
vote
2answers
118 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
120 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 ...
6
votes
1answer
4k 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
125 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
79 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
36 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 ...
