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
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 ...
2
votes
1answer
309 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 ...
15
votes
3answers
4k views

Why isn't vomit corrosive?

Vomit comes from gastric acid, right? And in gastric acid there is HCl and HCl is corrosive (strong), how come when I vomit, it doesn't destroy things that it (as the vomit) hits (such as floor, ...
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 ...
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 ...
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?
5
votes
1answer
270 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: $Question:$ ...
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 ...
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?
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?
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 ...
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 ...
2
votes
1answer
354 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, ...
4
votes
2answers
353 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 ...
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 ...
5
votes
1answer
200 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 ...
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?
4
votes
2answers
184 views

Where do the 31 spinal nerves start/meet?

Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that? Nominally, the beginning of ...
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
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 ...
1
vote
1answer
72 views

Any relevant knowledge/studies about voluntary goose bumps [duplicate]

I'm not entirely sure how normal this is, but since I was a child, I've been able to produce myself voluntarily a "chill" sensation that seems to start on my head and traverse the rest of my body, ...
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 ...
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?
2
votes
1answer
53 views

Why does crying lead to a running nose and reddened nose tip?

Why do we have a running nose for quite some time after crying? It persists even after we stop crying. Why is it so? I have faced this always. Also, why does our nose redden on crying for long?
4
votes
1answer
69 views

Why do we feel cold on having fever?

Why do we feel terribly cold on catching fever of any sort, however our body becomes hotter? Why is it that a rise in temperature makes the sufferer feel colder? Also, sweating symbolises betterment ...
4
votes
2answers
257 views

How many different protein coding genes are in the Human Biome?

There are approximately 20k protein-coding genes found in the human genome. This number is presumably very small when considering all the genomes found in the diverse microbes associated with the ...
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
107 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 ...
6
votes
4answers
3k views

Can nosebleed cause death?

Can Epistaxis or Nosebleed can be a of cause death?
3
votes
1answer
100 views

How much energy is required to blind someone?

As I understand the ravages of sunlight upon the (human) eye; the cause of ocular damage and blindness is too much energy delivered to the cones and rods that ultimately make up our eyes; so the ...
0
votes
1answer
123 views

Schedules of mating for men

It’s simple deductive logic to follow that for a species to survive it must provide it’s offspring with the best possible conditions to ensure it’s survival – either that or to reproduce in such ...
12
votes
1answer
1k views

Supercomputer Vs Human Brain

With supercomputers doing calculation in petaflops ($10^{15}$ Calculations per Second), have we crossed the speed of Human Brain?
6
votes
1answer
52 views

Does fasting improves immunity?

I have heard that fasting causes regeneration of memory cells(B- and T-lymphocytes) thereby improving immunity.Is this true? If yes, how?
4
votes
1answer
54 views

Can you measure ECG from a single location?

I want to make a DIY bracelet to measure my ECG. All I need is the interbeat interval. Can I design a bracelet on one arm only, with two electrodes slightly spaced from one another, and figure out ...
1
vote
2answers
65 views

How to know if your breathing is normal?

Is it possible for a device to measure how much air we breathe in and out over the entire day and at what rate? I think if we have access to this data we can compare it across people.
8
votes
1answer
503 views

Perspiration after drinking water

If we don't drink water for a long period of time(say,10 hours), as during fasting and then when we break our fast by drinking water why is it that our body starts sweating?
2
votes
1answer
59 views

Is it dangerous to eat a mutated eggplant descended from a radioactive ancestor?

What is the risk, if any, associated with eating a 100th-generation mutated eggplant derived from a radioactive ancestor? In another word, is that possible that organic toxin will be produced by the ...
2
votes
1answer
76 views

Is there any research paper state the pros and cons for human to be taller?

Is there any research paper state the physical health pros and physical health cons for humans to be taller? For example, shorter people seems to more likely to get involved in heart diseases and ...
2
votes
1answer
35 views

cerebral edema and blood pressure, pulse

What happens to blood pressure in cerebral edema; does systolic and diastolic rise equally? So the pulse actually slows down? Can't find anything about that, please help
2
votes
1answer
60 views

Biology Analogy

In my book are given several paired analogies with me being asked to give reason for them. I could solve all of them except this: liver = thrifty house-keeper I mean, I do not understand why the ...
1
vote
1answer
102 views

Why the scent of mouth gets dirty after not eating for a long time?

After a long time of hard workout,not eating and nervousness makes your taste and scent of mouth very uncomfortable and bad why this happens and is there any way to prevent it?
3
votes
1answer
71 views

Does tea have its effect if you have a sleep after drinking it?

If I drink tea, then go to sleep for a while, when I wake up, will the effect of tea still be on me (the refreshing effect)? Does it depend on the duration of sleep?
9
votes
2answers
1k views

How do we know the presence of light when our eyes are closed?

Last night I laid on my bed and tried to go to sleep with the light off. I closed my eyes (but hadn't gone to sleep). My younger brother touched the wireless mouse (which had laser) for the laptop. ...
0
votes
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 ...
5
votes
1answer
111 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) ...
1
vote
1answer
77 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
608 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 ...
0
votes
1answer
56 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 ...
2
votes
2answers
280 views

Is it theoretically possible to treat filaggrin deficiency with a dietary supplement?

http://f1000.com/prime/reports/m/3/2/ "Filaggrin is a highly abundant protein expressed in the uppermost part of the epidermis that is critical to the formation and hydration of the stratum ...