The morphological structure of human beings.

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36 views

How to maximize lung oxygen intake?

What method of breathing provides a sudden surge of oxygen into the lungs filling it as full as possible in volume and density. Deep breaths? Shallow breaths? Breaths taken while bent over? Deep ...
1
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2answers
27 views

Could humans theoretically see infrared better than regular light?

I have noticed that in infrared film, people's eyes reflect that light within their eyes much like nocturnal animals (and many other animals for that matter) do with regular light. I know that this is ...
0
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1answer
13 views

Specifics of decussation

Beginner question here: The definition of decussation I see is the crossing through the midline of a bunch of neurons. But I was wondering if there was a little more to it than this, because I'm ...
2
votes
1answer
56 views

Average face shape

I am doing face detection application where every face detected is inside a rectangle. The rectangle always contains some background behind the face and now I need to extract as much of the face as ...
0
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1answer
25 views

Development of vitreous humor

I have tried reading about development of vitreous humor but it is all very confusing. When does it first developed ? Does it renew itself ? Please provide reliable sources..
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1answer
30 views

Near point and far point of myopic eye

Suppose a person wears the specs of power -6D, the far point for that person is 16cm. But the near point of normal eye is 25cm. So, is the near point of a person with myopia (having far point less ...
0
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0answers
9 views

What causes human hair to go gray? [duplicate]

What causes the graying of human hair? Additionally, why does extreme stress bring it on faster?
0
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0answers
19 views

People say the cardiac cycle depends on blood pressure? How so?

I know what the cardiac cycle is. There are two phases diastole and systole. One is the relaxed, and the other is the contracted form of the heart. The diastole is where blood is pumped to the ...
3
votes
2answers
55 views

What is the evolutionary purpose of the topology of the human ear?

What is the evolutionary purpose of the topology of human ears? I understand why the ears may have a funnel-like shape but if the various "hills and valleys" do not amplify incoming sound, what ...
1
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1answer
46 views

Why are new vessels more permeable in microvasculature?

I know for microvasculature New microvasculature (arterioles, venules) are always more permeable as they lack pericytes. and then I have this sentence about new blood vessels (not specific) ...
6
votes
1answer
44 views

Healing rate of cut while suffering from a cold

I recently cut my finger fairly deeply with a box cutter and had to have it stitched. During the healing process I contracted a strong cold/mild flu (a sore throat and runny nose with a high fever, ...
3
votes
1answer
27 views

Is there a way to measure ATP usage in the brain similarly to fMRI?

Is there a way to measure ATP usage in the brain (or anywhere else) similarly to how fMRI works (measuring changes in iron resonance in oxygenated/deoxygenated blood)? Is there some sort of similar ...
2
votes
0answers
32 views

How do duplicate brain regions (ex: left/right amygdaloid body) operate together?

I frequently hear talk about parts of the brain like "Amygdala" or "Hypothalamus", so I looked them up in an app called "essential anatomy". What I see is that there's mirror symmetry, and most of ...
0
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0answers
22 views

How to predict the position of the femoral head center given surface anthropometric data?

Given surface measurements such as hip breadth and hip depth, how would you predict the location of the femoral head center?
0
votes
1answer
67 views

Breathing in and out

I was reading my textbook and it says that breathing involves inhaling and exhaling but it doesn't say whether they happen simultaneously or sequentially. Also is my overall understanding of ...
0
votes
0answers
40 views

Stomach sagittal section

Can anyone please tell me where is exactly the stomach in this image? This is a sagittal section from the University of Michigan Visible Human Browsers. Thank you.
4
votes
2answers
75 views

How would constantly growing nails have aided early human?

Nails grow rapidly and constantly, such that without constant artificial trimming they would reach lengths difficult to manage. How did this benefit early humans, say 200kya? Were they used like ...
5
votes
1answer
84 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
1
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3answers
82 views

What does orbital mean in orbital frontal cortex?

Orbital frontal cortex is where decisions are made. What does the word orbital there mean? I looked around in wikipedia and never find it.
2
votes
1answer
82 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
-1
votes
1answer
47 views

Hypothetically, what is the smallest functional form of human?

Since the my first encounter with doraemon manga, I've been wondering many things, one of them is the small light. Assuming we had an instrument, such as small light, which enabled people to grow and ...
2
votes
1answer
77 views

Scrotal temperature and vascularization

The testes (at least in human males) are vascular organs, the vascularization extending even o the interstitial spaces of the seminiferous tubules. The function of the scrotal sac, is to isolate the ...
0
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0answers
34 views

Natural angle of human eyes in most relaxed state

If a human is standing or sitting, is there a preferred angle in which the eyes are most comfortable when staring ahead? Maybe there's a clinical trial out there with research? The reason I ask is ...
0
votes
2answers
447 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 ?
1
vote
2answers
67 views

What does ophthalmologist see in your eye?

I always wondered what ophthalmologists see inside someone's eye and what they're looking for. The whole thing is a mystery to me. Are there any photos of what the eye of a patient looks like from the ...
1
vote
0answers
71 views

Learning first-year biology + anatomy via documentary?

Probably going to take first-year biology in ~4 months; so was thinking to go through MIT's 7.00x on EdX… However seeing at how popular this topic is, I was thinking there might be a fun documentary ...
3
votes
2answers
94 views

How far into a pregnancy is it before visible signs of it is apparent and risk of physical trauma increases

I'm doing research for a series I'm writing. in it the main character is pregnant however goes off to fight a criminal organization who have been killing her friends and i want her appearance to show ...
2
votes
1answer
80 views

Do people of the same height walk at the same speed?

I'm working on a project that concerns movement and the human body. Before I begin to experiment, I need an answer to a question I'm sure has an answer, but doesn't Google well. What I need to know ...
1
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0answers
58 views

Harmful effects of radiation from cell phone towers? [closed]

As per this article - http://www.thehindu.com/news/national/mumbai-citizens-link-cancer-to-cell-phone-towers/article5139166.ece , people living adjacent to cell phone towers claim to have developed ...
1
vote
1answer
216 views

Why does shaving dehydrate the skin? Is there an hormonal effect involved?

I want to understand why the face becomes dry after shaving and if shaving affects hormones? I've heard that after shaving, hair grows back faster, why? Shaving damages hair follicles and they become ...
2
votes
3answers
145 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 ...
3
votes
1answer
55 views

How do muscle relaxants work?

Do they act directly on the muscle and actually relax muscle tissue and ease spasms, or do they just prevent your brain from receiving signals that inform you of tight muscles? In the latter case, ...
0
votes
1answer
86 views

Is the resting state of the forearm in the pronated or supinated position?

It seems to me that my forearm is naturally in a more pronated position than the anatomic (supinated) position and that it actually takes work to make it hold the supinated position. Anyone an expert ...
3
votes
1answer
3k views

What is the standard deviation of adult human heights within sexes?

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations. What is the standard deviation of adult human heights within ...
1
vote
1answer
929 views

How are the paranasal sinuses linked with the capillaries in the ear canals?

Sinus congestion often seems to be accompanied by excess pressure on the outer ears (as anyone who has shared a transcontinental flight with an infant can attest to) or fluid buildup in the canals. ...
3
votes
2answers
3k views

Why do toenails grow much slower than fingernails?

As the title suggests, I've noticed that my fingernail grow much faster than my toenails. For instance, I usually trim my fingernails every two week or so, but for toenails the number would be about 6 ...
2
votes
1answer
51 views

How do cells figure out the big-picture shape?

I'm wondering what makes cells to divide (and stop) in such a way that they make our hands the shape that our hands are...
1
vote
0answers
83 views

Accurate Human Skull Model for Educational Purpose

I want to buy a model of Human skull for education purpose. However, I really want a very accurate model and at a decent price. I got the info that many of the available skulls in the market are not ...
1
vote
0answers
130 views

Would a spinal injury decrease human height?

A woman I know has been losing height at a rate of 10cm a year following a severe spinal injury. How is this possible? What kind of injury could cause such progressive loss of height? Could this be a ...
2
votes
2answers
937 views

Why does the sweat of children not smell like adults?

My kids sweat plenty in this hot heat, but they don't smell afterward. I on the other hand need all kinds of deodorant. Why doesn't kid sweat smell?
8
votes
2answers
635 views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
0
votes
1answer
89 views

Contracting muscles in humans

I study biology at school, and unfortunately for me, my program skips the muscles in humans chapter. I know (and mainly, feel) that the movement in one direction isn't created by the same muscle as ...
2
votes
2answers
2k views

What could cause hairs to gray at the tips but not the roots?

I have noticed that some of my sporadic gray hairs are gray at the tip side but oddly, not near the roots. Some are even only gray in the middle. I find all of this very counter intuitive, and I ...
0
votes
1answer
7k views

I'm 20. Can I still grow taller? [closed]

I'm 20, in about 6 months I turn 21. For some time I've been wondering whether there are natural, non-surgical and non-pharmaceutical ways that humans can continue to grow after reaching adulthood. ...
4
votes
1answer
83 views

Why do we yawn?

I've read a new study which suggests that yawning may help you keep a cool head. Also, the findings might hold some hope for sufferers of insomnia, migraines, and even epilepsy. Is there any ...
2
votes
1answer
86 views

Why do genitals feel frozen when freefalling?

I don't want to add much more about that. Since childhood I noticed a chilling effect, even when doing rollercoaster-type activities.
4
votes
2answers
247 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
1answer
978 views

Which blood vessel carries the most impure blood?

There is a question in my Biology textbook: "Which blood vessel in the human body carries most impure blood after few hours of meal." The answer is given as Renal artery. But I think the ...
6
votes
3answers
945 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 ...
3
votes
3answers
840 views

Why does the apex of the human heart usually point to the left?

In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...