This tag is for questions about the general anatomical features of human beings as opposed to the anatomy of non-human animals.

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9
votes
1answer
2k views

Why can hair grow without limit while eyebrow cannot?

I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit. Why can hair grow without limit while eyebrow cannot?
16
votes
2answers
368 views

Why would diffusion be faster across a non-specialised tissue?

The standard protocol for a person experiencing chest pains is to chew a 300mg aspirin tablet, the argument being that chewing rather than swallowing the tablet results in the aspirin entering the ...
3
votes
4answers
241 views

Bad Eyesight and Evolution

Why do many humans have bad eyesight, such as near-sightedness, which hampers performance in a wide variety of tasks? Shouldn't there be evolutionary pressure towards better eyesight?
11
votes
2answers
2k views

Will humans and animals be harmed by frequencies outside their hearing range?

The human ear (for example) is sensitive to frequencies from 20Hz to 20kHz. Any sound beyond that limit would not be heard by us naturally. Will it harm us (effect our ability to hear) when we hear ...
10
votes
2answers
2k views

How is eye color in humans inherited?

In high school we studied the inheritance of eye color, as it was explained to us in the most simple way: blue eye color is a recessive, monogenic, autosomal trait. Now I know that it is a bit more ...
0
votes
2answers
2k views

Will I grow taller? How can i tell? [closed]

I'm 17 and I'm about 160 cm and my weight is 47 kg . I just want to know if I will still grow taller ?
119
votes
4answers
17k views

Why do I only breathe out of one nostril?

I was just sitting with my hand next to my nose and I realized that air was only coming out of the right nostril. Why is that? I would think I would use both, it seems much more efficient. Have I ...
20
votes
3answers
24k views

If the brain has no pain receptors, how come you can get a headache?

I've read many years ago in books, that the brain has no nerves on it, and if someone was touching your brain, you couldn't feel a thing. Just two days before now, I had a very bad migraine, due to a ...
6
votes
1answer
110 views

Is it biologically possible for an adult's eye color to change?

Can it be that the adult eye can change color? Specifically my question is about a unilateral color change, such that the color of one eye remains constant, while the other changes color over time. ...
4
votes
2answers
310 views

Extraretinal photoreception in mammals? [duplicate]

A Finnish firm Valkee sells light-ear-plugs against thing such as jetlag. I asked a researcher in Aalto university how do they really work and he responded ...
2
votes
0answers
40 views

How much does a human brain's metabolic rate vary? [duplicate]

Possible Duplicate: How does brain energy consumption depend on mental activity? Our brains consume about 20% of our energy when we're at rest. How variable is a human brain's energy ...
9
votes
3answers
3k views

Why does human facial and head hair continue to grow?

Many people can grow extremely long head hair and facial hair. Are there evolutionary theories as to why this is the case? It seems like having long hair could be a disadvantage, and extremely long ...
6
votes
1answer
481 views

Why don't we have hair on palms?

We have hair all over the body except palms. What is the biological reason behind this? Thanks
4
votes
2answers
182 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
3answers
179 views

Mechanical cause of loss of consciousness

Consciousness is an electrical and chemical interaction in the brain, caused by neurons firing and chemical interactions. How does a mechanical "force" cause this to stop working? i.e. How does a ...
2
votes
1answer
618 views

Circulation through the liver in light of drug metabolism

I have a lingering question which stems from an answer that I gave to What hydrolyses aspirin within the digestive tract and blood stream? When a drug or any other substance is absorbed into the ...
1
vote
1answer
61 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 ...