Questions tagged [human-biology]

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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8 views

What's the purpose of segregating a virus from the blood and growing it in the lab?

I heard that the scientist in Australia found a way to segregate the 2019 NovCoronovirus from the blood. Does this mean they are one step closer to the cure? Why is virus segregation crucial in ...
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Why would only my first flu shots induce a fever?

In my mid 20s I began receiving regular influenza vaccines; one each year at the start of flu season as recommended by my doctor. The first time I got the vaccine, it induced a fever for several days,...
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Can a 3rd time ejaculation cause pregnancy?

When you already ejaculated for 2 times and then you ejaculated again for the third time, is there still a possibility you can i
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Is it due to caffeine or theobromine that cocoa works as a stimulant?

Recently I have been loving to drink cocoa. But I have heard about that it would keep me awake, so I searched on the Internet. Some people say that cocoa is a relaxing drink. Some say that the ...
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2answers
132 views

Why is HPV vaccines targeted for preteens?

Why is human papillomavirus products targeted to children before sexual activeness? Could all ages benefit from this vaccine even if they may have or have not contracted a form of HPV to prevent other ...
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1answer
49 views

Changes in dna from dioxin poisoning

A person sprayed with a dioxin, how long would it take for a dna change? Instant or over time? Would that person having children afterwards pass on any(if any) dna changes?
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Force applied to the human body

This is the basic premise of a physics question I have been attempting to solve over on the Physics SE. (I'm working on solving the actual science behind an old movie myth). How hard a punch hits ...
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1answer
11k views

Why can't people talk while inhaling?

Why do we have to exhale in order to talk? From looking on Wikipedia, it seems like it has something to do with the glottis, but I'm not clear on the mechanism that makes speech sound so different ...
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What is clinal outcome of osteoarthritis and rheumatoid arthritis?

What are the remodelling differences osteoarthritis vs rheumatoid arthritis? and What is clinal outcome of osteoarthritis and rheumatoid arthritis?
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Has a beneficial mutation ever been documented?

I am trying to find a case/study where scientists documented a mutation in an animal or human that was to the benefit of the host. The closest thing I have been able to find is sickle cell anemia (...
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32 views

Pressure measurement blood flow

During blood pressure measurement, when the flow within the arteries of the arm is interrupted, how is blood flow redistributed to the rest of the circulatory system? Is it possible that more blood ...
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2answers
2k views

Advantages of pain sensation?

The hazards of congenital insensitivity to pain (CIP) are well-known. This question is about the obverse: what selective advantage, if any, does the normal sensation of pain confer? I'm thinking of ...
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unable to balance standing while closing eyes [closed]

My Son age is 10 years.He is having over pronation problem. He is unable to stand while closing eyes. Please let me know if anybody knows some feasible answers to solve.
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Is it true that ethanol can have some positive effects?

I recently was reading this inforgrafics about excessive alcohol use. It is written: No one should begin drinking or drink more frequently based on potential health benefits I am surprised. Is ...
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Can food swallowed when a person is upside down reach the stomach?

If a person positions him/herself upside down and swallows food, will it reach the stomach against gravity? If so how?
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Is the lac operon repressed in the presence of both glucose and lactose?

In the presence of both sugars (glucose and lactose) will there be repression of the lac operon completely? I know that more glucose means less cAMP --> less CAP --> less positive regulation, and ...
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Do kids under a certain age not hear the warning beeps that smoke detectors make when they are running out of battery power?

I've always been very annoyed by those regular single beeps that smoke detectors start doing increasingly often as the batteries start to run out, to warn (and annoy) the user to replace the batteries....
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Is molecular oxygen (O₂) consumed in any process (in humans) other than acting as an electron acceptor for the ETC? [duplicate]

I know that molecular oxygen (O2) serves as the electron acceptor in Complex IV of the electron transport chain, which maintains the proton gradient that produces ATP for, as far as I know, every cell ...
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How do we sweat immediately after drinking water on a hot day?

On hot summer days, when I drink water to quench my thirst, my body immediately responds by sweating in 5 to 10 seconds or maybe less. How does our body detect the presence of water in the stomach so ...
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134 views

Coronary circulation

It is said that the coronary artery that gives the posterior descending artery(PDA) determines if the heart is right dominant(most cases) or left dominant. Is there any reason to this? Why PDA?
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How does HCl not burn our stomach?

How does the digestive acid (HCl) not burn the surrounding membrane of our stomach? It digests the majority of raw food we eat but how does it stay safely in our stomach? Also, how does the stomach ...
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What makes humans omnivores, and not herbivores?

Some vegans claim that humans are herbivores, not omnivores, and that we are not physiologically designed to eat meat (see here: http://www.peta.org/living/food/natural-human-diet/). "According to ...
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1answer
41 views

To what extent does loss of neurons in the substantia nigra affect movement?

There is a substance known as MPTP that is capable of crossing the blood-brain barrier. Once it does so, it is metabolized into a toxin called MPP+, which then selectively destroys dopaminergic ...
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1answer
56 views

How are the images of both eyes combined to form one image?

When you see an object by one eye, ex.right eye, you see it from the right direction and the opposite if you see it by your left eye, but when you open both eyes, the image appears somehow centric in ...
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3k views

Human body power consumption in still state

I'd like to know what kind of power human body needs to maintain life, in still state (average daily power consumption of an average man is also of interest). In terms of watts. I've only managed to ...
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pH on skin penetration of salicylic acid

I have found that at lower pH, there is more free salicylic acid (due to pKa of roughly 3), which is neutral/uncharged and then can penetrate the skin's oils which are non-polar. At higher pH, more ...
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How does salicylic acid (2-hydroxybenzoic acid) break down desmosomal proteins to exfoliate skin?

I've been searching for an explanation to salicylic acid's property of being able to break down desmosomal proteins, such as desmogleins in order to disrupt the outer layer of skin. Can someone ...
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Studying aging in humans (must be done in “real time”?) [closed]

I am asking this general question for members who are knowledgable about human aging research (especially at the molecular level). My assumption is that to study aging in humans directly would require ...
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1answer
2k views

Is it possible to have sleep paralysis while sleepwalking?

At least from a conceptual level, these two disorders don't conflict. The effect of sleep paralysis is being conscious while having the inability to consciously direct motor functions. Sleepwalking is ...
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Genetic variance for a behavioural trait among human populations

From this article from The Guardian: We instinctively assume that differences in behaviour that are in fact due to culture must be linked to – even caused by – characteristics of appearance. That ...
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2answers
3k views

How can the organic mercury compound Thiomersal be not dangerously toxic?

My intuition tells me that organic mercury compounds are absolutely toxic. Unimaginably, fundamentally, extremely and uncompromisingly toxic. I know that is not true for all doses. Thiomersal is the ...
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1answer
3k views

Why don't we build up an immunity to sore throat?

We often get sore throats once or twice a year, and it clears in a few days sometimes without any antibiotics. I was wondering why doesn't our body become immune after clearing a sore throat?
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873 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 ...
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159 views

How do we know that mild forms of rabies are nonexistent?

Wikipedia's rabies article says: "Death usually occurs 2 to 10 days after first symptoms. Survival is almost unknown once symptoms have presented, even with the administration of proper and intensive ...
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1answer
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How many times have the cells in a human body divided?

Every single cell in a multicellular organism can in principle trace its "ancestry" back to the zygote through a continuous chain of cell divisions. How many divisions have occurred in a typical cell ...
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3answers
306 views

Is sex a spectrum?

At the moment I'm especially interested in the question of whether biological sex is really a spectrum. Unfortunately I could not find any good answers on the Internet. Therefore I hope that some of ...
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8k views

Are there biological reasons why life expectancy is lower for men in most countries of the world?

I've been checking life expectancy figures for men versus women in many countries of the world and the figures for men sometimes are terrifying. Countries like Russia have a 12 years gap in disfavor ...
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1answer
157 views

Does estrogen increase muscular growth in females?

Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of ...
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1k views

Special visceral efferent

Why are special visceral efferent nerves are named as such? They are supplying motor impulses to muscles of pharyngeal arch, which are both skeletal(facial) and visceral(laryngeal) 1, so why only ...
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3answers
10k views

Why does it hurt when water touches cuts?

Why do we feel a burning sensation when water touches cuts/wounds? People suggest applying oil over cuts while bathing to prevent water touching it, but water is heavier than oil so it shouldn't work, ...
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3k views

Are there nerves in the umbilical cord?

I have always imagined that cutting the umbilical cord after birth might be painful. But I have always been confused about who would feel the pain and why. It occurred to me that the mother or the ...
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330 views

Serological assays measuring antibody response

Given that an appropriate immune response to a bacteria may be thwarted in an individual, including not producing all of the antibodies which are known to occur in people who have been infected, or ...
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535 views

Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
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Meiotic recombination hotspots

Im trying to find a proper and general file with chromosomal coordinates for meiotic recombination hotspots. I know that ucsc hgtables, has a table with recombination regions and their recombination ...
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Correlation seen with low billirubin levels but not the gene that causes Gilbert's syndrome

I was reading the following study on associations between bilirubin and CAD (coronary artery disease). They looked at the bilirubin association, and the genes that cause Gilbert's syndrome, which ...
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How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)?

How does lipoid pneumonia lead to acute respiratory distress syndrome (ARDS)? The vaping illnesses that have been happening on the news in the United States are being caused by the federal ...
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1answer
282 views

Do young children grow in spurts

It is a commonplace of my friends and relatives to remark that a young child (younger than 3 years) has had a recent "growth spurt". The underlying assumption is that young children do not grow taller ...
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Why is glomerular filtration called a non selective process?

According to Biology NCERT Class 11, Page 299, "Filtration is a non-selective process performed by the glomerulus using the glomerular capillary blood pressure." But the glomerulus filters out blood ...
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Does a breastfed infant gain immunoprotection due to intramuscular vaccination of the breastfeeder?

There is a claim that infants gain immunoprotection from breastfeeding. I am especially interested in specific protection against pathogens the breastfeeder (not necessarily the mother) has been ...
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706 views

What is the weight of a single human sperm (spermatozoon) compared to a single human egg

While the difference in dimension is well covered, I have been unable to find the mass measurements of each.