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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2
votes
2answers
58 views

What is a membrane potential?

I know this may be silly, but I am confused to what a membrane potential actually is. I understand that at resting membrane potential is -70- -80 mV. But what does that exactly mean and how does this ...
12
votes
2answers
28k views

How many human cells are there in our body, on average?

How many human cells are there in our body, on average? Wikipedia says 1013: Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in ...
3
votes
2answers
582 views

What happens if a person has the right side of the body totally removed (including the brain)? [closed]

I guess humans could live without just the right lobe of the liver or the right brain. Could a person without the whole right side of body survive? The left brain controls the right side of the ...
17
votes
2answers
2k views

Why was disease transfer to the Americas one-way?

It is well known that the European colonists brought many infectious diseases to the Americas, and that these had a deadly effect on the native populations, because they had no immunity to them. Were ...
1
vote
0answers
43 views

How to stop or slow down the process of growth of hairs? [closed]

Is it possible to slow down or stop hair growth? If yes, then how is it achieved?
5
votes
1answer
268 views

Evolution of umbilical cord and reason of its elongation

To answer a question myself, recently I've read that Years and years ago, a long umbilical cord enabled a woman to grasp her baby after birth and run away from predators" Update: $Question:$ ...
7
votes
2answers
3k views

Can one die from pain?

Is it possible that a human or any other creature can die from pain? I googled and found different answers. Some articles say Yes while others say No.
6
votes
4answers
165 views

Why do fat people tire quickly?

Fat people have a large amount of calories (energy) stored, but I have noticed all time when they do physical activities they get tired fast in comparison to fit people - why does this happen?
3
votes
1answer
91 views

Is there a difference between drinking water straight from the tap compared to leaving it to sit?

An idle question - if a glass if filled from the tap and consumed immediately, it contains some dissolved oxygen from the physical process of moving through the pipes & tap. If left out ...
18
votes
5answers
4k views

Why do the two hemispheres of the brain control the opposite sides of the body?

Why does the left hemisphere control the right and the right hemisphere control the left? I googled it but didn't find a good answer regarding this. Could someone explain? Does this adaptation help ...
1
vote
1answer
41 views

Gastro-intestinal physiology reference

I am a physicist but I have always wanted to understand how my digestion takes place in as much detail as possible. I have no idea about books or reference on the subject of Gastro-intestinal and ...
13
votes
1answer
571 views

What light intensity starts melatonin release in humans?

I'm interested in whether any studies have determined the intensity of light at eye level that starts melatonin release in humans. I know that: melatonin release is suppressed by blue light with ...
3
votes
1answer
50 views

What happens to human dopaminergic reward system once a teenager becomes adult?

I've recently heard a podcast which explained teenage impulsivity and novelty seeking in part by "Lowering the baseline dopamine activity in the reward system" "Increase in dopaminergic reward in ...
2
votes
1answer
135 views

How much time does it take a human body to replace all of its atoms?

Mikel Vsauce (Vsauce youtube channel) said in his video that it takes about 5 years for the body replace all of its atoms, while in asapscience youtube channel they are claiming that it takes 10 ...
3
votes
2answers
170 views

Standard Process Identification of New Disease outbreak Causing Pathogen

Is the any standard procedure or protocol followed for the identification of cause of new disease outbreak(or new pathogen)? Is it different for different countries?
6
votes
1answer
60 views

Why ml scale blood retrieval is required to run a blood test?

Substances found in blood are present at microscopic scale and tend to be invisible to the unaided eye. Why is a whole vial of blood (at ml scale) is required to assess the presence and concentration ...
5
votes
3answers
134 views

What is the point of having evolved two nostrils?

How would having two nostrils be advantageous to your sense of smell or your ability to breath? I already hypothesized that either one of the nostrils could act as a back up for when another gets ...
2
votes
1answer
305 views

Do human anal glands have any function?

Anal glands in all kinds of animals play a range of diverse functions - providing fat for preening feathers or waterproofing fur, generating distinct scent, even repelling predators. None of the ...
6
votes
2answers
133 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
votes
0answers
75 views

Human body control? [closed]

What can we consciously control in our bodies besides our muscles and brain (thought, memory, etc.)? Is the notion Bio Feedback related to this matter? EDIT: I mean I can move my muscles at will but ...
2
votes
3answers
1k views

What organs are absolutely needed by the human body?

The title is my question: what organs are absolutely needed (fatal if injured/removed) by the human body and perhaps animals in general? I'm not asking which organs are mechanically replaceable, but ...
4
votes
1answer
847 views

Difference between intervertebral and vertebral foramina

In the human spine, what is the difference between intervertebral and vertebral foramina? Is it just a matter of perspective and do they refer to the same thing or are they different?
9
votes
2answers
14k views

Why do vaccines cause your arm to hurt?

When you get a shot for a vaccine (for example, the annual flu vaccine), the nurse frequently indicates that your arm will ache for a day or two, maybe more. This ache is typically not just a pain ...
3
votes
1answer
109 views

The smell from eating asparagus

I am wondering about one thing. I have read different accounts of this (prior to reading it on Wikipedia), so I am wondering. Here are the two versions I have read: asparagus leads in a certain ...
4
votes
2answers
182 views

Can a virophage potentially be used to cure a viral disease?

Wikipedia states "Virophages are satellite viruses that inhibit or impair the reproduction of the auxiliary virus." Is it theoretically possible for a virophage that doesn't hurt the human body to ...
7
votes
1answer
507 views

Do identical twins have the same fingerprint?

When there is every thing same from their genes to their phenotype so then why they don't have same fingerprints?
15
votes
8answers
8k views

Why have humans evolved much more quickly than other animals?

Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel. Meanwhile, a lion is still a lion and a ...
64
votes
5answers
2k 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 ...
1
vote
1answer
39 views

Why are high levels of epinephrine and low levels of cortisol signs of stress?

According to my psychology textbook (Psychological Science: Modeling Scientific Literacy), high levels of epinephrine and low levels of cortisol are signs of stress. However, earlier in the textbook ...
18
votes
3answers
1k views

How and where, in the human brain, are memories stored?

Background I am a computer programmer who is fascinated by artificial intelligence and artificial neural networks, and I am becoming more curious about how biological neural networks work. Context ...
1
vote
2answers
83 views

How precise is EEG?

Imagine we want to read impulses within single neurons in the brain. Can we do that now for a single region within the brain? If not, what is the smallest region that can be monitored for an activity ...
1
vote
0answers
52 views

Is there a difference between endorphins that are released while physical activity and sex/masturbation?

I observerd myself and I can identify two different types of "happines". First - called by me - After Pleasure : Occurs AFTER (and last long) long activity that require from me engagement focus and ...
4
votes
2answers
351 views

Why doesn't the human skin grow back exactly how it was before being damaged?

Very simple: Why (and how) is regenerated skin different from original ? As we know we lose skin cells that becomes the dust in out homes and it always grows back to full thickness right ? So when I ...
12
votes
3answers
776 views

In Japan, the official average body temperature is 36.0 °C. Why so different from that of Europe?

The Japanese Wikipedia states that the average human body temperature is 36.0 °C (here,"ヒト"). The statement references the data from the Japanese government. Actually all of my Japanese friends think ...
2
votes
1answer
353 views

Why do humans seem so much more prone to disease than animals? [closed]

It seems like when we observe animals in the wild, the occurrence of noticeable disease in adult individuals is much lower than in humans. Why? There are a number of reasons that this could happen, ...
5
votes
1answer
199 views

Why does the sacrum fuse together?

Everywhere I look describes how the 5 sacral vertebrae start fusing together during adolescence and are totally fused by the time you're 30 or so. But nobody seems to explain why this happens. It ...
3
votes
1answer
61 views

Is there revolution in humans since the first homo sapiens sapiens

In a thinking mood, I was wondering if the human species has changed since they have first become homo sapiens sapiens. I asked myself this question because I was thinking about how we will evolve ...
1
vote
0answers
46 views

Can two women have a daughter? [duplicate]

In vitro fertilization is a pretty routine procedure in which a female egg is fertilized by sperm outside the body. Recently apparently there has also been something similar in which the genetic ...
4
votes
1answer
90 views

Why do some women have menstruation-like spotting throughout their pregnancy?

An interesting question that was asked during a lecture about human reproduction: what is the biological mechanism behind some pregnant women getting monthly spotting that they mistake for a regular ...
2
votes
0answers
41 views

Viagra for pain management

Not all men who take Viagra experience any sexual side effects about 40% have no change of sexual abilities on the pill. However like many women the drug in such cases cause a strong pain reduction ...
5
votes
2answers
396 views

What happens to lactic acid I eat?

Let's say I drink some Kefir Milk, what happens to the lactic acid in the Kefir Milk that has entered my digestive system?
7
votes
2answers
620 views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
3
votes
1answer
131 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 ...
1
vote
1answer
90 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 ...
6
votes
2answers
161 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
5
votes
1answer
53 views

Can neurotransmitter depletion cause short-term drug tolerance?

I'm curious to know if neurotransmitter degradation factors into drug tolerance and neural conduction and, if so, to what extent. As I recall from textbooks I read as an undergrad, one mechanism of ...
8
votes
1answer
1k 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 ...
27
votes
1answer
4k views

What causes morning wood?

Sometimes men wake up with an erection in the morning. Why does this happen?
5
votes
2answers
106 views

biologically speaking, what's the difference between sleeping and just resting?

I can lay down in a rested position with my mind at ease, but no matter how relaxed I am or for how long i do it, it seems I'll still need sleep eventually. What's the difference - what is occurring ...
4
votes
1answer
44 views

What does hemozoin do?

My bio book refers to HEMOZOIN that is responsible for the shiver during malaria. How does hemozoin work to raise the body heat?