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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6
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2answers
305 views

At any given moment, how much energy is stored in the human body as ATP?

At any given moment, approximately how much energy is stored in the human body as ATP in the ADP-P-bond? This of course depends on what type of cell it is and the activity of the individual in ...
1
vote
0answers
30 views

Why is exocrinous pancreatic cancer so lethal when compared to others?

I know it seems far fetched, but I would really like to understand why an interference with the regulation of production of pancreatic exocrine products (and which are they) is so lethal. I know that ...
5
votes
1answer
383 views

What is the maximum altitude where humans can survive?

What is the highest altitude that a human can survive without being pressurized? Let's assume that oxygen and heat/insulation are not the limiting factors? Why I asked.
5
votes
1answer
39 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
1
vote
1answer
210 views

Do human somatic cells have 46 chromosomes all the time?

As far as I know, a human somatic cell has the cell cycle: Interphase and Replication (mitosis). In interphase the cell has 2 growth phases (G1 + G2) and a synthesis one (S phase being in between G1 ...
4
votes
1answer
143 views

Why do we sleep?

While we do know that the human body is regulated by a circadian clock that keeps humans on a sleep/wake cycle, we don’t really know why. Sleep is the time when our bodies repair tissues and perform ...
1
vote
0answers
17 views

Ions in different cell compartments

I would like to understand the distribution of metal ion concentrations (such as Mg2+) in the different cell compartments. I tried very hard but still couldn't find such information. Could anyone help?...
4
votes
1answer
248 views

Could a trans-female person ever become pregnant?

I was told that a transgender person, which I will define as anyone assigned male or female at birth that identifies opposite to that assignment, could never become pregnant conceptually, due to the ...
4
votes
1answer
61 views

Are there testosterone receptors in female mammary tissue?

Does female mammary tissue have receptors for testosterone hormones? Do male hormones influence female mammary glands, as female hormones influenced the male mammary tissue, such as in gynecomastia?
0
votes
0answers
91 views

Is hypoxia/anoxia the ultimate cause of death?

I know there are different causes of death for humans like heart disease, cancer, stroke, injury and so on, but i was thinking if in every case in the last instance death is due to hypoxia/anoxia. ...
0
votes
1answer
227 views

Why do we have two eyes? [duplicate]

Humans, animals and birds all have two eyes. Why? In addition to why two instead of one, why aren't there more than two?
1
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0answers
27 views

is there a difference in meaning between the terms “bone architecture” and “bone structure”?

I'm wondering whether "bone architecture" and "bone structure" mean the same thing, or whether they refer to two different concepts. In this article - http://rheumatology.oxfordjournals.org/content/...
6
votes
1answer
77 views

Is eradication of the Common Cold possible?

This is a thought experiment, but everywhere I've read seems to say that colds ALWAYS come from someone else. There's no mention of a cold arising in someone without it coming from another infected ...
0
votes
0answers
40 views

Life after decapitation? [duplicate]

I saw a video where an ant lost its head and was still walking for some time. If this is possible for an arthropod, what keeps it from working with a vertebrate? (Humans, especially)
1
vote
1answer
66 views

Genotype of children conceived after stem cell transplant?

If you have sickle cell disease and have a succesful stem cell or bone marrow transplant, your blood type changes to AA. But what about your future children? Do your sperm or egg cells continue to ...
0
votes
1answer
53 views

Can skin be removed and replaced so that it maintains its original cellular structure?

The cells in our body that form tissue, such as our skin, are interconnected. I would think that cutting out tissue or trying to repair/replace it, as is done in surgery, or after an injury, could not ...
1
vote
0answers
53 views

Why can't men produce milk, just like women? [duplicate]

This might seem a bit weird, but why can only women produce milk? Wouldn't it be more beneficial to our species if all humans could produce it? I can't think of any reason only one gender would need ...
0
votes
0answers
33 views

Why is alcohol purged from the body more slowly when we sleep?

It is a popular belief that when you get asleep after drinking alcohol, in the morning you have higher level in your blood than if you stayed awake the whole night. Is this true? If so, why? Is it ...
1
vote
1answer
39 views

Who and when was the first human diagnosed with hemophilia, or considered a carrier?

The earliest case I can find is Queen Victoria of England, who ruled from 1837-1901. Is this the first hemophilia case on record?
7
votes
1answer
359 views

What will happen if a foetus is Rh- and the mother is Rh+?

If a mother has Rh-negative blood and her foetus has Rh-positive blood it will result in rhesus incompatibility and lead to erythroblastosis fetalis. What will happen if the reverse occurs, when a ...
2
votes
1answer
42 views

Are all tastes just a combination of sour, sweet, bitter, etc.?

For example, can the taste of pineapple be isolated to just a certain amount of "salty-taste-triggering-molecules" and "sweet-taste-triggering-molecules" etc.? Can our current understanding of the ...
18
votes
2answers
2k views

Can Biologists identify all viruses?

I went to the doctor today with my girlfriend, and the doctor said that she had a virus but doesn't know which one and she should let the infection heal with some rest. The fact that the doctor didn'...
3
votes
2answers
117 views

Do humans contract more physical sicknesses and diseases than animals do? [duplicate]

I wondered: If I get into the library and look into the medical section it is evident that there are thousands and thousands of different human physical diseases. But if I look into the section of ...
1
vote
1answer
62 views

Breathing becomes harder in certain wind conditions

I'm not sure if this is the right site to ask this, but it seemed like the best option. I've observed on myself that, if I stand on a train platform and a cargo train drives by, creating strong, ...
4
votes
1answer
80 views

Why does a Urinary Tract Infection cause a strong, persistent urge to urinate?

There are plenty of articles on the fact the a urinary tract infection (UTI) causes frequent and urgent urination. For example; on this National Institutes of Health webpage. My question is: Why ...
-2
votes
1answer
193 views

How may the age of a child be estimated when required to do so, in video-graphic evidence?

How may it be possible to roughly conclude that a subject in a select piece of video-graphic evidence presented, is in fact a child, i.e. without the subject being, physically examined? Is it ...
2
votes
1answer
73 views

Reseach on feeling pain of other people

I'm more of a tech than bio kind of guy, but I have read and learned a lot alongside of my girlfriend's education. Which is very interesting!! Currently I want to investigate : people claiming to ...
4
votes
1answer
137 views

Why do you retch when you see something disgusting?

Why do you retch when you see something disgusting? I imagine it is some sort of evolutionary response, although I can't see the connection between receiving a signal that unhealthy conditions are in ...
5
votes
0answers
30 views

Can we predict a person's tolerance to cold exposure during excercise?

Being an amateur athlete and student of anatomy I've always wanted to know if there is a formula for determining an unconditioned body's tolerance to cold temperatures while exercising. I know the ...
2
votes
1answer
85 views

Which part of the reflex arc takes the longest time?

If the reflex arc is composed of 4 parts: Activation of sensory receptors, Conduction to and from the CNS, Transmission across the neuromuscular junction & Activation of the muscular contractile ...
0
votes
1answer
67 views

How body loses more fat in CO2 form than in sweating form? [closed]

Yesterday, I saw TV Game Show. There is question like this: Body loses more fat in which form? It gave 4 options: 1) CO2 2) sweating 3) xxx 4) xyz sorry i didn't remember 3 & 4 options. ...
3
votes
2answers
141 views

Can an argument be made that humans are 90% bacterial?

On the blog, All about Scientist in Microword: Microbiology, I read the post We are 90% bacteria, actually, which says that humans are 90% bacterial cells. If this is the case, then why don't we ...
5
votes
1answer
153 views

Colorblindness in females and random X chromosome inactivation

From Annenberg Learner: Because the X is inactivated randomly in cells, one cell could have the maternal X inactivated, while the adjacent cell could have the paternal X inactivated. This causes ...
0
votes
1answer
55 views

When does lactation occur?

High levels of estrogens and progesterone antagonize prolactin’s effect on the mammary glands, and it’s only after the placenta has been removed and the levels of estrogens and progesterone has ...
3
votes
2answers
134 views

Do intestinal flora have the same DNA as their host?

Please bear with me, this is not my professional field and I might be mixing things up. In an explanation why seeds won't start growing in one's intestines, the explanation given was that foreign ...
1
vote
1answer
64 views

Do vitamins protect you from common cold? [closed]

Do vitamins (taken as pills) boost your immune system, and make you less likely to contract diseases such as common cold or flu?
3
votes
1answer
634 views

Are there human-ingestible liquids that do not contain water?

My son asked me a question that stumped me: Is there anything a human can drink that does not contain water? It stemmed from a conversation in beverages in general where I was pointing out that they ...
3
votes
1answer
285 views

Why do humans masturbate? [closed]

Why does masturbating seem to be like an addiction? What controls or initiates the urge to masturbate? Is it good or bad or both and why is it so? I have heard guys who say that the do it ...
6
votes
1answer
1k views

Why does a fetus drinks and urinates into the amniotic fluid?

I was reading this website saying that fetuses urinate into the amniotic fluid. It also mentioned that, because we drink the amniotic fluid, we’ve been drinking our urine for months. However, why do ...
3
votes
1answer
83 views

Corpus luteum during the luteal phase and gonadotropins

Does the corpus luteum operate independently of the hypothalamic-hypophyseal-ovarian axis? I know that hCG sustains the corpus luteum in the absence of FSH and LH, but in an ovarian cycle where there ...
2
votes
0answers
77 views

Why does it take many sperm for one sperm to fertilize an egg?

Hundreds of acrosomes must undergo exocytosis to digest holes in the zona pellucida. This is one case that does not bear out the adage, “The early bird catches the worm.” A sperm that comes along ...
0
votes
1answer
84 views

Acrosomal enzymes and the female reproductive tract

My textbook wrote that the reason why acrosomal enzymes are so securely contained within the sperm (thus needing capacitation to facilitate their release) is to prevent any premature release in the ...
2
votes
0answers
109 views

Cause of a extra vertebra in the human body [closed]

Most people have five vertebrae in their lumbar (lower back) region, which are named L1 to L5. However, some people possess an additional lumbar vertebra located below the L5. This extra vertebra, ...
2
votes
1answer
118 views

How does the pancreatic beta-cell know how much insulin to secrete in response to glucose?

How do $\ce\beta$-cells know how much glucose is in the blood? I know that when glucose enters a beta cell it triggers the cell to produce insulin. $\ce\beta$-cells trap glucose by converting it into ...
6
votes
2answers
383 views

Why can't our eyes smoothly transition from side to side without focusing on a moving object?

Why are we not able to slowly and smoothly look from side to side, or up and down in a single and smooth transition, given that we are able to do this if our eyes are focused on a moving object?
0
votes
0answers
68 views

Why exactly does a scarf help against a neck pain and a sore throat?

I was going out without a scarf and as this day my neck was more sensitive; after a while my voice was rasping, I needed to cough and my neck was hurting slightly. After coming home I put on my silk ...
-5
votes
1answer
224 views

Why are plants classified in living things? [closed]

@Volunteers Beware that I am none of the biological magnates. Nor a philosopher. This is just a sign of curiosity. And, I want only an intuition that enables me to see the difference. As far as I ...
0
votes
1answer
43 views

How DNA programs the first cell in womb into a human [closed]

Sorry if you see me silly. I am just a programmer happens to be curious about biology... So far I understand how DNA make protein, how cell divides, how one composed of cells->tissues-> organs. But,...
0
votes
0answers
42 views

Why does histamine release in Type I hypersensitivity help in case of parasites?

The IgE system exists because the same events which lead to often-life threatening complications of allergy, in presence of parasites are helpful in their elimination. The tissue injury mediated ...
0
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0answers
24 views

Pathogenesis of type IV hypersensitivity

In hypersensitivity, as I understand it, a normal immune response gets excessive, misdirected or wrongly regulated to cause tissue injury. The various types determine the various ways in which the ...