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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8
votes
2answers
256 views

Why do we have two of some organs, but not all?

We have two eyes, but we don't have two hearts. Why do humans have two of some organs, but not all?
2
votes
1answer
244 views

Where does female ejaculate actually originate from?

It's common knowledge that it's released via the urethra, but where does it originate? If it doesn't come from a part of the clitoris, then why is the clitoral glans called the clitoral glans? How ...
10
votes
1answer
126 views

Unilateral damage to vagus nerve

Context: The vagus nerves supply the neck viscera, heart, lungs and gastrointestinal tract. They join around the oesophagus to form the oesophageal plexus. Question: Would damage to one vagus nerve ...
4
votes
1answer
951 views

How are arms different than legs?

Ok, this is a bit of a tangent question, but it came up yesterday and I didn't know the answer: How are arms and legs defined physiologically? For example, we say humans have two arms and two legs, ...
6
votes
1answer
3k 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
0
votes
0answers
51 views

Why is my right hand's thumb on the left side and my left hand's thumb on the right side?

My daughter just asked this question, and I could not provide a thorough answer. My first speculation is that it allows one to manipulate an object using one' both hands simultaneously (if the thumbs ...
0
votes
0answers
30 views

If I were to flush enzymes down with a cellulose rich food, what would happen?

Lets say I were to consume an adequate concentration of cellulase and cellubiose with a cellulose rich food. Would nothing happen, would I successfully extract calories from the cellulose, or would it ...
1
vote
0answers
19 views

Hair turning back to original color [closed]

I am 86 years old and my hair has been solid gray for over 15 years. Now it is turning back to its original color. (red) I took a three week dosage of 10,000 Biotin in December. Could that cause it ...
4
votes
0answers
315 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 ...
3
votes
1answer
27 views

Is curling the fingers considered digit flexion?

Is curling the fingers considered finger flexion and straightening the fingers considered finger extension? I feel like this is correct in everyday language, but I am not sure if it is correct in ...
1
vote
2answers
68 views

The alignment of fingers in our hand

I noticed that in my hand the index and middle finger are aligned in one direction and the next two fingers somewhat in the opposite direction. My question is, why are our fingers aligned in that way? ...
4
votes
2answers
125 views

Headshot = instant kill? [closed]

While whatching a film, I've been thinking about how does a headshot kill someone, and how long does it take? For example let's say you've beeing shot by a normal (police) handfired weapon - no ...
4
votes
0answers
25 views

Is the knee locking mechanism present in animals?

We study in human anatomy that when the knee is in full extension, the femur slightly medially rotates on the tibia to lock the knee joint in place. This reduces the work required to be done by the ...
5
votes
1answer
168 views

Do humans have skin cells that trigger oxytocin release in the brain?

I was reading an article by Montgomery on the therapeutic effect of pets (Boston Globe, January 12, 2015), and I found this quote: All animals appear to have cells directly under the skin that ...
0
votes
0answers
104 views

Are Young Girls Stronger than Young Boys?

According to "common wisdom" the average man has, as a proportion of his body weight, 50% more muscle mass than the average woman. This is in addition to how the average man is several inches taller ...
1
vote
0answers
16 views

Is the amount of blood same in the pulmonary and systemic foetal circulation?

We learn that the stroke volume is the same for the right and left side of the heart. So the amount of blood in either circulations should also be the same. (is it? I myself doubt this statement. As ...
4
votes
1answer
70 views

Cross section through the right arm question

Is the largest drawn vein on first attached pictue v. brachialis or did they make a mistake and it's actually v. basilica? Picture 1: Cross section through the right arm (source: Thieme, General ...
1
vote
1answer
27 views

Anatomy of the ear canal

When you insert your finger into your ear, you hit a dead end. You can't insert your finger into the auditory canal. What's this dead end called, the medical term for it?
6
votes
3answers
3k views

3D models of adult male brain in the Blender software? Any open-sourced version for research?

I am trying to find 3D model of brains. I am particularly interested in adult-male -brains in Blender-model. I could find such 3D models of brains for sale here but because I am researching I would ...
4
votes
0answers
27 views

Does variation in human gut length vary predictably with diet of ancestors?

Background: Numerous online searches, textbooks and other sources seem to pin the average length of the human gut from mouth to anus (oroanal) between about 5-10m in length. To pick a reputable ...
0
votes
1answer
61 views

What is the correlation between hand and neck flexibility? [closed]

I am trying to understand this statement in the book, Mudras, Yoga in your Hands by Gertrud Hirschi: There is a direct relationship between the hands and the neck since the nerve paths run through ...
5
votes
1answer
6k 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 ...
0
votes
0answers
23 views

What is the function of the Moderator band?

The moderator band in the right ventricle is a band sorts of muscle which consists of a significant branch of the AV bundle. Does it mean it delivers impulses to the anterior papillary muscle faster? ...
17
votes
3answers
468 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 ...
0
votes
1answer
36 views

Difference between the spinal cord and vertebrae column [closed]

What is the difference between the spinal cord and the vertebrae column, they both run through from the head to the abdomen. Does any one have any idea.
1
vote
1answer
25 views

What would be “Sternum-Intermediate” distance?

I've asked this question on the English Language & Usage board, not being entirely sure whether this question is strictly medical, or just English knowledge suffices to answer. Do note I am no ...
1
vote
0answers
13 views

Does this habit present any harm? [closed]

Sometimes I am able to put one knee down on the floor, rest my weight on that knee, and then relax it in order to make the knee cap go up and "crack" the knee. I can do this with both knees, I think ...
1
vote
0answers
28 views

Atlas from human brain structures to 3D coordinates?

I would like to visualize specific human brain structures in the three dimensional space and compute specific geometric properties of these brain structures (size, centroid, etc). Therefore, I am ...
2
votes
2answers
66 views

Skull size of Homo naledi

I want to 3D print the skull of the newly discovered Homo naledi. The printing data can be found here: http://morphosource.org/index.php/Detail/MediaDetail/Show/media_id/7300 Where can I find the ...
1
vote
0answers
50 views

What factors limit a shape and size of an organ

We all know that anatomy deals with structure of human system. I am interested in knowing the factors that determine the shape and size of each organs in the body. For example, we know that kidneys ...
2
votes
1answer
73 views

Is blood pressure in the aorta and brachial artery the same or different?

Does the blood pressure at the root of aorta equal the blood pressure in the brachial artery? I've heard it does, but it doesn't quite seem to make sense as I'd think the blood pressure would be ...
5
votes
3answers
273 views

Symmetry of species [duplicate]

I've got a silly question, sorry for that. I know, that we probably have no the right answer and the current answer could be "that's evolution, external conditions". I'd like to speculate, why most of ...
4
votes
1answer
54 views

Are there testosterone receptors in female mammary tissue?

Does female mammary tissue have receptors for testosterone hormones? Do male hormones influence female mammary glands, as female hormones influenced the male mammary tissue, such as in gynecomastia? ...
2
votes
1answer
147 views

How large is the variability in human bone thickness, and is “big boned” a real thing or not?

My girlfriend is arguing that there are "big boned" people, I read some articles that there is no such thing but she still didn't believe in me because she saw some articles too that big boned people ...
0
votes
0answers
44 views

Indentation between trapezius and scapula

I've been studying the muscles of the back, and while browsing through reference pictures on google I've come across this image (coloured lines edited in by me): What I'm confused about are the ...
0
votes
1answer
116 views

Why do we have two eyes? [duplicate]

Humans, animals and birds all have two eyes. Why? In addition to why two instead of one, why aren't there more than two?
1
vote
0answers
22 views

is there a difference in meaning between the terms “bone architecture” and “bone structure”?

I'm wondering whether "bone architecture" and "bone structure" mean the same thing, or whether they refer to two different concepts. In this article - ...
1
vote
0answers
52 views

Why can't men produce milk, just like women? [duplicate]

This might seem a bit weird, but why can only women produce milk? Wouldn't it be more beneficial to our species if all humans could produce it? I can't think of any reason only one gender would need ...
3
votes
1answer
100 views

Are the intestinal microbiota substantially different within a diverticulum of the colon?

From the Wikipedia page for the vermiform appendix: This proposal is based on a new understanding of how the immune system supports the growth of beneficial intestinal bacteria, in combination ...
2
votes
1answer
205 views

Why does the kidney of a cow have lobules, why the kidney of a human hasn't any?

The kidney of a cow has lobules, while the kidney of a human hasn't any. I can't think of any reason why it would be good for a kidney to have lobules. It would be good if the kidney needed to have a ...
-2
votes
1answer
190 views

How may the age of a child be estimated when required to do so, in video-graphic evidence?

How may it be possible to roughly conclude that a subject in a select piece of video-graphic evidence presented, is in fact a child, i.e. without the subject being, physically examined? Is it ...
13
votes
2answers
2k views

The Uniqueness of DNA Paradox

How can everyone have unique iris and fingerprints? After a certain amount of human beings have lived on earth, wouldn't it be possible to exhaust all possible combinations? The same principle ...
11
votes
3answers
4k 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 ...
1
vote
1answer
51 views

Which organs need to have fluid compartments in order to develop properly?

I am a student, slightly struggling with the new concept of fluid compartments. I know that there are two main types of fluid compartment, extra and intracellular fluid. I also read that most organs ...
4
votes
1answer
55 views

Unable to identify a muscle of the anterior thorax

I was watching an YouTube Anatomy Video which goes over the major muscles of the anterior superficial thorax. There is a structure present throughout the video which goes unmentioned, and I can't seem ...
3
votes
1answer
122 views

Effects of HRT on transgender(M to F) physiology and athleticism.

I often heard of athletes in the Olympics who would be accussed of having an advantage because they were intersexed. Now I know transgenderism and being intersexed are not the same thing, but they ...
2
votes
1answer
320 views

What is the distance between the sciatic nerve and the colon at the closest point?

Is it possible that a full colon impinges on the sciatic nerve? Is there anything that physically separates the sciatic nerve from the colon?
0
votes
0answers
9 views

Are sensory receptors neurons and if not whats the difference in structure with sensory neurones? [duplicate]

I am confused with the structure of sensory receptors because it seems to be like that of a sensory neuron.
6
votes
1answer
125 views

What is the function of the human eye white?

If you have a look at the eyes of most animals, you never see the white part unless the eyes are averted. In contrast, humans always have the whites visible because the iris is quite small. The only ...
2
votes
0answers
52 views

Front versus back in animal anatomy [closed]

Throughout various species, there seems to be a clear distinction between the front and the back. The musculature of the front, when engaged, closes or curls up the body, protecting it, while the ...