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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2answers
78 views

Is there a biological reason for spreading food intake into breakfast-lunch-dinner?

I keep hearing over an over how humans can satisfy their entire daily caloric need in one sitting at a fast food restaurant. At the same time I'm looking at the kitchen plates, cups, etc, and they ...
3
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1answer
38 views

How much of the jejunum is bypassed during gastric bypass?

There is both long and short limb bypass surgeries. I want to know how much of the jejunum is bypassed with each procedure.
1
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1answer
111 views

Why doesn't Diabetes cause death by starvation?

The main cause for diabetes is lack of insulin in the body. Insulin is the hormone that allows body cells to absorb glucose from the blood. With out insulin, the body cells can't get glucose from the ...
0
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1answer
83 views

How HIV Affects and Its Treatment using Combination Therapy

Can someone please help me with the following questions. I've written my specific questions right after the text question. Human immunodeficiency virus (HIV) is a retrovirus. Its genome is a single ...
3
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1answer
53 views

What is an explanation of the dual role of calcium hydroxide in teeth?

Calcium hydroxide induces dentine formation in permanent teeth, while it causes resorption of tooth in deciduous teeth. How is this dual role explained?
4
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1answer
71 views

Enlargement of thyroid gland

Why does thyroid gland enlarge both in hypothyroidism and hyperthyroidism? Hypothyroid goitre is due to lack of iodine in diet and hyperthyroid goitre (Exopthalmic goitre, Grave's disease) is due to ...
1
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1answer
75 views

Biology in romantic love

Hi could anyone explain the biological basis behind romantic love. What is the biological basis of falling in love?I know that serotonin and dopamine are secreted when we first fall in love. What ...
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2answers
154 views

How much vanilla will kill a person?

I received a gift that is a jug of Pure Mexican Vanilla. Having never dealt with large quantities of vanilla, it made me curious as to what would happen if a person had too much vanilla. I understand ...
3
votes
1answer
287 views

Do hormones make men think of sex?

I remember hearing a saying that goes like "men think of sex every 7 minutes (or seconds?)". I take this saying to mean that men have sex related thoughts more often than women. I'm interested if ...
7
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1answer
728 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?
4
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1answer
453 views

What causes Acne?

What exactly is going on biologically at the molecular level with acne and causes breakouts? Hormonally, there is a lot going on but I'm curious about what is going on chemically.
0
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1answer
22 views

Biosphere that simulates sun and moon shifts

Is there an enclosed biosphere that artificially simulates the movement of the sun and moon at increased intervals? It is known that the sun and moon alter plant movements therefore I was wondering ...
55
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4answers
1k views

Is there a reason why human eyesight and plants make use of the same wavelength of light?

The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the ...
5
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1answer
86 views

Which part of human eyes is getting tired?

It's a thing of common sense that if you read, drive or look at computer screen for too long your eyes will get tired. They burn, itch and try to close all the time. But I was wondering which part(s) ...
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4answers
47k views

What's the maximum and minimum temperature a human can survive?

This is a question that has been in my mind since I was a kid. I'm not a doctor, nor even a biology student, just a curious person. What is the minimum and maximum temperature a human body can stand ...
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1answer
59 views

Simultaneously using both hands - How does that work?

Is some part in one hemisphere the decision maker and "calling the shots" - controlling the opposite side's hand "directly" and controlling its own side's hand through the corpus callosum. Or: is ...
2
votes
1answer
95 views

Are Asian people 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 ...
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0answers
60 views

How many blood types are there? [duplicate]

In total how many blood types are there? And why do people normally know only 8 of them? (A+, B+ , AB+ and O+ and Rh- counterparts)
0
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1answer
51 views

level of organisation of proteins

Is there any disulphide bond in a quaternary structured protein? If yes, please provide examples. In tertiary structured proteins, what is(are) the most important characteristic(s) of tertiary ...
5
votes
2answers
448 views

The probability of indirect human fertilization?

What is the probability of conception in situations when sperm isn't directly ejaculated into the woman's vagina, like: The man's or the woman's hands come into contact with sperm, for example when ...
0
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0answers
49 views

What are hot spots on human body?

Recently I have just discovered that a certain amount of the mobile phone frequency can be absorbed by human tissues. For example, this is the SAR info of iPhone 4s: Head: 1.180 W/kg 1 g Body: ...
5
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1answer
260 views

Can HIV be transmitted via breastfeeding?

If a pregnant women is HIV positive and she is treated with medicines to deliver a normal child,can she transfer the HIV virus back to her normal HIV free child by colostrum?
6
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1answer
434 views

What is the normal duration of human sexual intercourse?

Wikipedia is saying: Men's typical ejaculatory latency is approximately 4–8 minutes How the researchers measured this? How did they know if the test subjects weren't suffering from premature ...
35
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1answer
7k views

Why do Humans not produce Vitamin C like other mammals?

Why do most mammals produce their own Vitamin C? Why do Humans not?
3
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1answer
67 views

Can frequent ultrasound diagnostics be harmful?

Are there any short or long term effects apparent in tissues if a zone (or the whole) of human body is scanned with ultrasonic waves often?
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1answer
54 views

Can someone provide resources on human electromagnetic frequencies?

Pardon all of my questions below. I'm basically looking to find online resources regarding my inquiry. If you can answer any of them off the bat, that would be awesome!! It seems that humans and ...
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2answers
285 views

How are proteins formed?

Somewhere, I have read that we need to consume proteins to make amino acids to make new proteins. What does it suggest? How do we make proteins from proteins?
4
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1answer
82 views

What happens to fecal matter if it's continually re-eaten?

After class today, the topic of eating one's one fecal matter came up. There was a sharp divide as to how people thought the defecations would change. I realize this is a bit of an odd question but ...
3
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1answer
93 views

Tap vs. mineral water for drinking

I was told a human should drink a small glass (0,3 liter) of mineral water per day to get the minerals. What is the rationale behind this? What is the difference between tap water and mineral water in ...
2
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1answer
60 views

What is the biological function of nose hair?

What is the biological function of nose hair? In general, can we consider underarm hair and pubic hair to be vestigial structures?
5
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1answer
84 views

Why is there no cure for Dandruff?

It looks like a simple problem, affecting almost half of the population at the post-pubertal age and of any gender and ethnicity [wikipedia]. What is so complex about finding a cure? Also, if you know ...
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0answers
30 views

Does healthcare and therapy affect natural selection adversely? [duplicate]

In the last 200 years or so, healthcare and therapy has been revolutionized. Mortality rates are going down everywhere. Even if the disease is terminal, medicine can prolong life for quite a while. ...
2
votes
1answer
94 views

What is the minimum air pressure the human body can tolerate if oxygen supply is not an issue?

Disregarding hypoxia, what is the minimum air pressure that the human body can tolerate? (i.e. at what air pressure would the blood start to boil, or skin start to burst, or whatever else might ...
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1answer
60 views

Religion and Genetics

Are there studies that investigate the heritability of believing in supernatural things (or related concepts)? Or stated differently. Are there studies that ...
6
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1answer
180 views

What is the effect of garlic on intestinal flora?

Now that we can compare whole microbiomes, has there been investigations on the effect of garlic (or diallyl disulfide, its main ingredient) on intestinal flora? From the proven antimicrobial ...
0
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1answer
70 views

Drinkable liquids that dont contain water [closed]

Are there any drinkable liquids that don't contain water? By drinkable I mean it would not harm me by just drinking it, like water.
5
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2answers
1k views

Which human cells have the longest and shortest lifespan?

Which cells in a human have the longest lifespan? Which cell has the shortest lifespan?
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1answer
84 views

Applying saliva to mosquito bites

Is it true that; when you apply your own saliva to a mosquito bite it would stop itching ?
3
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1answer
393 views

What is in Mosquito bites?

I was wondering what is in the mosquito bites, which causes the swelling of the skin at the bite and also the itching. I know that the mosquito injects some stuff, but what is it?
4
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1answer
759 views

Why do veins look blue?

I know that veins carry oxygen. Veins look blue because the oxygen-depleted blood in them is blue. Is this true??
6
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1answer
6k views

Can a person really die quickly from biting their tongue?

A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible? The internet turns up millions of ...
9
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1answer
193 views

What would be the conduction speed of A-alpha fibers, were they unmyelinated?

It's known (Hursh 1939) that myelinated axons exhibit the behavior $v = 6d$, where $v$ is the propagation speed [m/s] and $d$ is the axon diameter [μm]. A related relation for unmyelinated axons is ...
2
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0answers
86 views

Human female chest model or data representation?

I am looking for professionally used representation of female chest (I know how it sounds ;). Generally - a model comprehensive enough to effectively represent human chest, with focus on breasts. ...
2
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1answer
35 views

What is inside IDL (intermediate density lipoproteïn)?

I am studying about the endogene lipidcycle in the human body and I know that VLDL (very low density lipoproteïn) is made in the liver and that it contains triglycerides and cholesterol from your food ...
2
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3answers
77 views

If the top epidermal layer is burned away, what is it replaced with?

If the squamous (top) layer of epidermis, or skin, is burned or damaged in another way, will it then be replaced by the next layer of below? Also, from where does the basal membrane originate? Does ...
2
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2answers
49 views

Cancer growth and cell division [closed]

I am confused about the prerequisites for cell division and cancer. Which of the following is necessary for the cell cycle to progress? Hormones Growth factor Cyclins Cyclin dependent kinases ...
1
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1answer
59 views

Why do we suffer abdominal pain after we get very angry or stress?

You also realize probably, when we get so much anger or high levels of stress, after some point we have terrible stomach ache, like really heavy pain. Why is that? How stress or anger can effect our ...
2
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1answer
78 views

What is the evolutionary cause for various finger lengths?

Why are the lengths the way they are with middle finger the longest?
0
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1answer
67 views

What is atrial fibrillation?

I am wondering exactly what a-fib is (causes and symptoms). I would really appreciate having a sample of an EKG with it (because in my limited research, I have found it nearly impossible to find just ...
2
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1answer
42 views

What cells don't have a primary cilium?

It is often stated that most cells in the human body have a primary cilium. Which ones don't? For which cells is it unknown?