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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5
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0answers
120 views

What will happen when humans are injected with plant growth hormones

Will plant growth hormones (PGHs), (let us consider auxins for example) poison our body or not? I do realise that when you eat a shoot, auxins get digested and are less likely to be poisonous but when ...
5
votes
0answers
54 views

Are high sounds worse for your hearing than low sounds?

From about 80 dB it is possible to suffer loss hearing after a couple of hours. But does it make a difference what frequencies those sound waves are or is it just the volume of the sound in dB that ...
7
votes
2answers
80 views

Do babies conceived naturally or artificially have any differences in long-term health?

Are there any long-term differences in children conceived via artificial insemination or sexual intercourse, pending that the mother successfully delivers the child?
18
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2answers
2k views

Why do we like salt?

A few friends of mine told me that salt provides zero nutritional value to us, and in fact can harm our bodies. Now, these guys are medical students, and being an engineering student myself, I decided ...
7
votes
1answer
2k views

What is Mendelian Randomization, and how is it used to infer causality in epidemiology?

Studies of human traits and diseases are inherently confined to observational studies, known as epidemiological studies. This can make it very hard to determine what actually causes a particular ...
22
votes
2answers
2k views

Why is it advised that infants are fed mother's milk?

I have heard that mother's milk is preferred over other baby foods, because it contains immunoglobulines (secretory IgA), and other essential nutrients. But why is mother's milk so special? Any ...
11
votes
3answers
422 views

During starvation, does the human body do anything to prioritize which organs receive nutrients?

When food is scarce, the body slows its metabolic rate to conserve energy. Are there any other systems or processes that prioritize which organs receive nutrients?
-5
votes
1answer
210 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 ...
10
votes
3answers
1k views

What is the purpose of gluconeogenesis?

The gluconeogenesis pathway seems quite pointless to me. I don't understand why an organism would want to spend energy to create a molecule that can then be metabolized again for less energy? The ...
0
votes
0answers
36 views

Do both the Sperm and Egg must be at exactly 7.4 pH for fertilization?

I suddenly came across this article and it says that for human conception to occur both the sperm and egg must be at exactly 7.4 pH - not 7.0, nor 7.7 but 7.4. If conception depended on such exact ...
3
votes
0answers
37 views

Are all genes transcribed in differentiated cells?

My textbook tells me that it’s specific transcription factors that allow for a different set of genes to be expressed in different cells (differential gene expression). My book gives the example of ...
2
votes
1answer
81 views

When you take a very cold or hot bath how is that influencing your breath?

It looks like when you take a cold shower or bath your veins get smaller and when you take hot shower your veins get wider. But is that right and do you need to breath more in both cases because you ...
6
votes
1answer
60 views

Is Zika suspected of causing birth defects only if contracted during pregnancy?

There seems to be growing evidence that a recently spreading strain of Zika virus is in fact linked to microencephaly and other birth defects in newborns (see here, here, and here for examples). I ...
8
votes
2answers
235 views

Why did women historically have such a high mortality rate during birth?

Historically women had a relatively high chance of dying while giving birth. At first thought it seems to me that this would be a disadvantage for the species for the obvious reason that a dead ...
5
votes
1answer
102 views

Why is it always Sodium that we talk of in blood pressure?

Why is that we emphasize so much on sodium in blood pressure? I understand that it is a major extracellular ion, but, it also is tightly regulated. So when something is that tightly regulated, won't ...
5
votes
1answer
580 views

What is the function of the polar bodies produced during oogenesis?

Why are polar bodies produced during oogenesis in human females? I read that polar bodies are produced during meiosis so that the oogonium (or gamete mother cell) can be converted into a haploid ...
5
votes
1answer
174 views

Do humans have skin cells that trigger oxytocin release in the brain?

I was reading an article by Montgomery on the therapeutic effect of pets (Boston Globe, January 12, 2015), and I found this quote: All animals appear to have cells directly under the skin that ...
1
vote
0answers
38 views

Why are oral cells (or tissues) more heat resistant? [closed]

When we are having meals, such as enjoying hot pot and drinking hot water, we only have a sense of "warm" in our mouth, or even along the organs in alimentary canal. But when we put our fingers into ...
3
votes
1answer
131 views

How is pain induced by blunt and sharp objects?

Normally, when something touch you, you won't feel pain. With a great force "touching" you, you will feel pain. However, if something that is spiky makes contact with you, you will feel pain. So, how ...
8
votes
1answer
1k 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 ...
0
votes
1answer
89 views

Identifying an Unknown Blood Type [closed]

The following case study has a student working with blood samples to identify their blood types (A, B, AB, and O). Consider the situation and answer the questions. A student is given eight ...
3
votes
1answer
75 views

Is a bone marrow transplant limited by sex?

Can a female patient get transplanted with bone marrow of a male donor and vice versa?
1
vote
1answer
78 views

How can a blood test give information about rickets?

Can we detect rickets from a blood test? What evidence pf rickets is in the blood and how is the blood treated to detect rickets?
4
votes
0answers
18 views

Why do kupffer cells not attack sporozoites of malaria?

During malaria, why don't kuppfer cells (hepatic macrophages) attack the plasmodium and stop schizogony, thus saving us from the disease?
12
votes
4answers
21k 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, the building is totally ablaze and he can do nothing but run ...
6
votes
1answer
46 views

Would constant light or fading light be registered as more wakefulness promoting by the Supra Chiasmatic Nucleus?

During the fall and winter season, a number of people are experiencing Seasonal Affective Disorder. One of the way it has traditionally been treated is with a dedicated lightbox - a very high ...
0
votes
0answers
138 views

Are Young Girls Stronger than Young Boys?

According to "common wisdom" the average man has, as a proportion of his body weight, 50% more muscle mass than the average woman. This is in addition to how the average man is several inches taller ...
0
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0answers
85 views

Is natural selection still at work in humans in the 21st century? [duplicate]

There has been some disussion on this site about some aspects (e.g. evolution of eye sight, or height, or the effect of medicine, or evolution the past $\sim10000$ years). My question is really more ...
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0answers
21 views

Can humans extract calories from all roots? [closed]

Roots are used for storing plants' energy, which suggests that humans could extract the calories by consuming them. However, I have been unable to find any substantial sources on consuming the roots ...
3
votes
2answers
334 views

Why do our eyes “wrap” hue from UV to IR?

On the high-wavelength side of things, we see almost-infrared as reddish, with a slight tinge of magenta. On the low side, we see violet fading into the same magenta color. Why is that? You can see ...
1
vote
0answers
20 views

Is the amount of blood same in the pulmonary and systemic foetal circulation?

We learn that the stroke volume is the same for the right and left side of the heart. So the amount of blood in either circulations should also be the same. (is it? I myself doubt this statement. As ...
2
votes
1answer
30 views

What is the name of the property of viruses can activate a second time, with different symptoms?

The Varicella zoster virus causes chickenpox in children and shingles in adults. It appears after the initial infection, it can go dormant in the nerve, and reactivate itself decades later. In ...
1
vote
1answer
41 views

What is the name of the property of viruses that can go dormant in the host for 30 years?

The Varicella zoster virus causes chickenpox in children and shingles in adults. It appears after the initial infection, it can go dormant in the nerve, and reactivate itself decades later. My ...
9
votes
2answers
2k views

How do people who have lost both of their legs produce red blood cells?

As far as I know, just leg bones produce red blood cells. So, how people who lost their both legs produce red blood cells?
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0answers
19 views

Variation of human body temperature during physical exercises [closed]

I'm currently doing a research on "Variation of human body temperature during physical exercises". I have to study about Heat equation in 1-D , 2-D and 3-D. Are there any good resources that I can ...
3
votes
0answers
42 views

What is the name of the category of viruses that affect only one side of the body?

The Varicella zoster virus causes chickenpox in children and shingles in adults. When the virus attacks as shingles, one of its distinguishing characteristics is that it only affects one side of the ...
4
votes
0answers
74 views

When and why did humans start disliking the way we naturally smell? [closed]

Like many animals, humans produce a myriad of scents from sweating, bacteria, possibly pheromones, etc. Many of these scents are used throughout the animal kingdom for mate choice, recognition of ...
1
vote
1answer
45 views

Lookup for transporter locations in humans

I am interested in several transporters and cotransporters (eg SLC12A1/2 and many others), more precicely, in (human) organism that are made of cells containing those transporters. So does anyone know ...
3
votes
3answers
312 views

Is there a known glucosepane cross-link breaker?

I read the following on wikipedia: There is, however, no agent known that can break down the most common AGE, glucosepane, which appears 10 to 1,000 times more common in human tissue than any ...
7
votes
2answers
9k 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 ...
4
votes
0answers
36 views

Does variation in human gut length vary predictably with diet of ancestors?

Background: Numerous online searches, textbooks and other sources seem to pin the average length of the human gut from mouth to anus (oroanal) between about 5-10m in length. To pick a reputable ...
1
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0answers
25 views

What are the most efficient sources of nutrition to add lean mass? [closed]

In conjunction with an exercise routine, what sources of nutrition will best help increase lean body mass. Most non-hormonal exercise supplements risk causing liver damage and gout due to excess urea ...
2
votes
0answers
51 views

Real Wine and Real Bread Superfoods? [closed]

On NPR news on the Fm Radio a doctor said wine and bread is the best 2 things you can eat together? A practice observed to this day by Christianity although the bread and wine are badly stripped of ...
3
votes
1answer
95 views

Does our brain contain an innate function about closing only one eye?

I wasn't sure where to post this, but biology seemed fitting for me. Sorry if I'm wrong. I was wondering why, when we close both our eyes and look at light, it is clear we can see the light even ...
1
vote
0answers
54 views

How would a human brain change if it existed in isolation? [closed]

How would a human brain change if it didn't receive any signals for a longer period of time (e.g. 1 month)?
2
votes
1answer
32 views

Advantage of GCPRs over RTKs or other receptor protein kinases

My book lists two important differences between GCPRs and receptor protein kinases: GCPRs do not directly activate a signal transduction pathway. It only does so indirectly, via a G protein. On the ...
2
votes
1answer
107 views

What are the highest and lowest amplitude values in ECG for humans?

I'm currently trying to parse the records captured from an ECG device and display them on a mobile application. I am wondering what the highest and lowest possible amplitude values for ECGs are in ...
1
vote
0answers
32 views

how to visualise a network of proteins complex? [closed]

I would like to know how to visualise a complex of several proteins lets say I have a list of proteins ...
28
votes
2answers
5k views

How long do your eyes need to adapt to darkness and reach full contrast?

I heard you should wait some time until your eyes adapt to darkness and are able to see smallest luminosity differences, otherwise you might overlook faint objects in the ocular. Are there any rules ...
2
votes
2answers
52 views

awakening effects of light

I tried reading by light from a neighbouring room and felt sleepier than if my own lights were on. Is there a formula for the intensity of light vs physiological preparation for sleep(calcium, ...