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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1answer
39 views

How does ANF increase GFR?

ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
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0answers
44 views

With humans, is being transgender innate, or caused by social factors?

In humans, is being transgender something that is innate, or is it caused (or made more likely) by social factors such as their political beliefs, their religious views or their social environment?
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0answers
15 views

Does the use of a Thiazide diuretic affect the ability of a hair follicle to absorb substances?

Thiazide diuretics are on the World Anti Doping Agency's, as well as the International Olympic Committee, list of banned substances due to it ability to mask illegal substances in urine. The rapid ...
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2answers
56 views

What percentage of human body's cells are contained in blood?

What percentage of human body's cells are contained in blood vs. the rest of the body?
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2answers
29 views

Can ingesting substances that are produced by the body cause a permanent withering of the organs that produce the substance?

This question is about substances such as insulin and some vitamins that the human body is able to produce on its own. Some substances that are produced by the body are also present in various body ...
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1answer
33 views

How does the Pectoralis Major work when doing a bench press?

Disclaimer, I'm not a biology undergrad and I only know the basics about muscle movement. I know that doing a bench press works the chest, and specifically the Pectoralis Major because, well, I feel ...
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2answers
70 views

What does it mean to have different “metabolism”?

We hear talk of different body types, and that it is more difficult for certain people to lose weight than others. On the other hand, when my physician recommends that I lose weight, they say that it ...
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3answers
3k views

Superhuman eyesight

My ten year old son was reading car number plates that were too fast, too far away and at the wrong angle for any of us to read or even believe that it was possible for him to read. We thought he was ...
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1answer
47 views

Genetic abscence of backpain among teen girls? [closed]

I heard a study somewhere (I can't remember where) that claimed that teenage girls are genetically absent to experience high degrees of backpain, specifically from rigorous exercise. Strangely, of ...
3
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1answer
198 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 ...
3
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2answers
480 views

Is lemon water an alkalizing agent in the body?

I was recently having a discussion with someone about whether lemon water actually increases the pH of your body (by which I assume they mean the blood); their claim was that once Citric acid was ...
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1answer
126 views

How can we measure cardiac output?

I could find a way which could find it by body oxygen consumption and there is another way to measure it by injecting drugs — measuring cardiac output by the so-called “indicator dilution method,” a ...
3
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1answer
105 views

What’s the reason for isovolumic contraction and isovolumic relaxation?

During cardiac cycle, there are two periods in which the heart volume doesn’t change, but there is a change in tension/pressure. It takes about 0.25-0.35 second to achieve this change. I searched in ...
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0answers
40 views

Is it possible that weak memory is due to interference between signals in the brain?

"Weak memory", as used in this question, refers to the inability to retrieve a memory that a person otherwise knows he has memorized earlier. An example of this is some fact snippet that the ...
2
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1answer
63 views

Biphasic T wave caused by digitalis toxicity

Digitalis is a drug that can be used during coronary insufficiency to increase the strength of cardiac muscle contraction. But when overdosages of digitalis are given, depolarization duration ...
4
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1answer
87 views

What actually are thoughts? [closed]

The human brain consists of neurons that transmit impulses like wires that conduct electricity.I am confused about where are our thoughts stored and what really are thoughts? For example if I think ...
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0answers
193 views

Why are fingerprints different even in identical twins? [duplicate]

Why are fingerprints different from person to person? It can't be genetics. Even identical twins has different sets of fingerprints. What is the deciding factor that form and shape our fingerprints?
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0answers
28 views

Neural correlates of the function of the cardiovascular system?

Are there any known neural correlates of the function of the cardiovascular system? I'm looking for research results that use standard brain imaging techniques (e.g. electroencephalography, ...
13
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0answers
2k views

Why do we experience temperatures below 37 degrees Celsius as 'hot'? [duplicate]

We always prefer to be in 20-25° C, although our core temperature is about 37°? Why is our skin temperature lower than our core temperature?
8
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1answer
148 views

Why aren't green eyes more prevalent?

Why aren't green eyes more prevalent, given that the green allele is dominant over the blue one? My understanding is that human eye colour is determined by two genes: 1) HERC2, with alleles Bx, BB ...
3
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0answers
37 views

Can we artificially increase human growth using HGH?

Robert Pershing Wadlow was a man who lived in the early-mid 1900s and had hyperplasia of his pituitary gland, which caused him over-produce human growth hormone (HGH) and grow to nearly 9 feet ...
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2answers
288 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?
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0answers
56 views

How does estrogen influence collagen synthesis?

Through what mechanisms does estrogen interact with collagen synthesis? Especially in the context of elevated estrogen levels and genesis of purpura simplex .
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2answers
67 views

What is overdiagnosis?

What is overdiagnosis ? I have searched this Wiki result but didn't understood at all. Can you please explain the first two line of Wikipedia : Overdiagnosis is the diagnosis of "disease" that ...
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1answer
169 views

Why do we get 'bags under our eyes'?

Why do these circles form around the eyes if somebody is tired? And why does fatigue express itself around the eyes this way? Can I get eye bags very quickly in another way? ...
2
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1answer
42 views

Why does uterus have to be prepared every month for fertilization?

I'm just curious why it has to happen every month when the uterus could have been prepared from the beginning and kept that way throughout life or till a certain point. But why make and break it every ...
3
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1answer
357 views

Name (and meaning of the absence) of the white semicircle at the base of the fingernail?

At the base of fingernail, there is a white semicircle (see on the first picture). But sometimes there isn't one. My questions are: what is this white semicircle on the fingernail, and what causes ...
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1answer
19k views

Why Does Salt Water Help Sore Throats?

I am having some trouble understanding how salt water, a simple solution, could so effectively remove the pains of a sore throat. I do believe that the answer is closely related to hypo/hyper-tonic ...
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1answer
54 views

Human Species of Males/Females [closed]

Why is it that when there is discussion about Race/Subspecies it is never about the genetic/physical differences between males and females. So every argument has been about physical and geographic ...
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5answers
1k views

Why do we age? or Do we have a theory of senescence?

There seem to be a number of ideas about why we age. Hypotheses include the gradual accumulation of cell metabolic products affecting organism function and the reduction of telomere length during cell ...
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2answers
58 views

SNPs and locations

I am new to reading raw DNA. When comparing two people's raw data, why does one person have a different SNP than the other, at the same location, on specific chromosome? But on a different chromosome ...
13
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2answers
2k views

Why I have to pee more often in low temperature? [closed]

I realised that I have to pee more often in winter or simply the temperature is low. Is there any scientific explanation, or just simply psychology?
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3answers
160 views

How does menstruation proceed during one period?

I'm simplifying things here: A. Does a woman bleed constantly, like a drop every 10 minutes? Two hours without pad or tampon and your underwear is dirty? or B. Does a woman bleed suddenly a ...
9
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1answer
139 views

What senses are active while sleeping?

During sleep, our body activity decreases. I am wondering on the extent of the lowering of this activity regarding our five senses. Clearly, the sense of touch is still very efficient since shaking a ...
9
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3answers
222 views

Why did humans become bipedal?

Somewhere in evolutionary history homo started walking upright and became bipedal. You hear these hypotheses that, by walking upright, they could see better across the grassy savannas to escape ...
2
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2answers
141 views

Agony, Hydrophobia and viruses in the light of evolutionary principles

I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice. Agony as the last ...
3
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1answer
113 views

Why are sperm cells not attacked by the female immune system? [duplicate]

Whenever a foreign particle enters into someone's body, it is attacked by the white blood cells. I just want how it is that, when sperms enter the female body, they are not attacked by the the woman's ...
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2answers
2k views

Why don't breast enlargements leave any marks of surgery on breasts?

If we get stitches, we get marks left on the skin, but there are no marks for breast enlargements. I saw a YouTube video about a breast enlargement wherein a doctor makes a cut. Where does the cut ...
5
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3answers
124 views

Which fruit compounds affect the speed of fructose absorption?

Blood fructose levels are not regulated by insulin in the human body. This means that the body absorbs pure fructose very fast, and it raises the blood fructose levels rapidly. Do fruits/ vegetation ...
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2answers
81 views

What are the differences between a benign tumor and swelling?

What are the differences between a benign tumor and an injury related swelling? And can swellings due to injury turn into a benign tumor?
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1answer
73 views

What kinds of cells does human saliva contain?

I have heard that our saliva contains cells. What cell types can be found in human saliva?
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0answers
15 views

Swellings with Variegated consistency

I am interested in knowing the names of all swellings with variegated consistency. I have come across the following: Malignant swelling with partial necrosis Caseated tuberculous lymph nodes ...
1
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1answer
29 views

Dehydration from caffeine, alcohol and other

Tea, Coffee, Beer, Coke etc… I wonder if the benefit from amount of fluid we get from them is bigger or smaller then the handicap of dehydration. In other words it is worth to drink them if we want ...
2
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1answer
60 views

Dehydration by a tea, coffee, beer etc

For the long time I am trying to find out if the following is truth: They say that some beverages dehydrates. I heard that about tea (sometimes green, sometimes black, sometimes both), coffee, beer ...
3
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1answer
278 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: ...
3
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1answer
91 views

Are nutrients absorbed in human esophagus?

Following this question regarding absorption in human oral cavity (sadly not yet fully answered), I'm curious if any nutrient absorption occurs during the descent of food through the esophagus. And ...
8
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1answer
3k views

What is the female equivalent of the morning erection that some men experience?

There was question about what causes "morning wood." It was answered that the erection in the morning is caused by decline of norepinephrine during REM sleep. Which in part allows to prevent ...
7
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1answer
76 views

Can people with paralyzed eye muscles see?

As far as I am aware, the saccades of the eye are central to sight perception. If the eye is held still, the human stops seeing, even if light is reaching the retina and the visual pathway is intact. ...
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1answer
57 views

What specific sensory nerves act as receptors for “pins and needles” (neuropathy)?

According to this excellent answer, the difference between "pain" and "pins and needles" (neuropathy) is that different receptors (sensory nerves) trigger in reaction to different stimuli. Different ...
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1answer
46 views

How and where do nerves share pathways to the brain?

I am interested in understanding how pain receptors send signals to the somatosensory cortex (the part of the brain that registers various nerve signals such as pain, presure, temperatures, etc). ...