The study of the structure of organisms and their parts.
Questions tagged [anatomy]
258 questions
84
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Why is the heart not in the middle of the body?
All mammals that I can think of have a high degree of bilateral symmetry (In fact, almost every animal I can think of is like this).
So why is the human heart not exactly in the middle of the body? An effect of this is that one lung is slightly…
DrZ214
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How come large herbivores have such thin legs?
Edit:
This question is very similar to this and related to this one (though the latter focuses on homology instead of scaling laws). However, the answer to this question is far more comprehensive, in particular it offers a plausible explanation why…
Kevin Kostlan
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Why Is Most Life Symmetrical Externally But Not Internally?
Mammals, reptiles, arachnids, insects, etc are all as far as I am aware symmetrical in appearance.
Take a human for instance, make a line from the top of our head right down the middle. However, internally it is not the same. Our organs excluding…
cryptic ツ
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Is C. elegans always observed with precisely 302 neurons? Are there ever individual viable exceptions?
This answer mentions that the C. elegans hermaphrodite has exactly 302 distinct neurons. This has made it a very effective model for a variety of types of biological research, including neurology and cell differentiation. It is also currently the…
uhoh
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Do "shooting" animals exist?
The well-known cartoon imagery of porcupines shooting their quills at opponents in a fight is just that: a silly cartoon concept that isn't real. But it makes me wonder, does that mechanism exist elsewhere in nature?
Are there any animals whose…
Mason Wheeler
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Does the octopus have an anus? What does it look like?
Octopuses are cephalopods, which have separate anal and oral openings. Indeed, descriptions of the cephalopod GI tract clearly depict an anal opening.
However, I am very confused about how this applies to the octopus. I don't think I've ever seen…
Superbest
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Why are there no known animals with an odd number of legs?
In my 6th grade science book it is said that there are no three legged animals, and that no animal with an odd number of limbs exists. I checked Wikipedia and could confirm this:
There are no known naturally occurring three-legged animals
On…
user31782
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Evolutionarily, why do male rats and horses lack nipples?
Developmentally male rats don't have nipples because (reddit)
Testosterone release in the fetal male rat happens before the stage of mammogenesis where the teat is formed whereas other species halt that same process after the teat is…
mic
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Do the majority of fish lack scales on their heads?
Based on pictures, it seems to me that a vast majority of fish species that have scales do NOT have scales on their heads.
Is that fact true?
To make this properly answerable:
lets' define a "majority" as >70% of fish species. But frankly, I'm…
DVK
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Evolution of long necks in giraffes
In this question, the OP uses giraffe necks as a supportive example of evolution. Is the mechanism described in this post accurate? At some point, I thought I remember hearing that giraffes did not evolve long necks to reach higher food resources,…
Daniel Standage
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Skull mystery on beach
The skull was found on a beach on the Sechelt inlet on Canada's pacific coast. A marine environment.
What species is this skull from?
Rusty biologist
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How many cells does the smallest animal have?
Note: question rewritten to prevent misunderstanding and make it more answerable
I know that some small animals like C. elegans display surprising sophistication with a very small number of cells. But I wonder, among the animals with known/estimated…
rumtscho
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What is the morphological difference between Leydig cell in human and pig?
The pig is only an example, just an animal. Leydig cells have protein inclusions (Reinke crystals) that are mostly made of crystallised lipofuscin. They are secretory inclusions i.e. cells formed in secreting cells.
An example of Leydig cell in…
Léo Léopold Hertz 준영
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Using anatomical terms for human organs and parts of plants
I know how to apply anatomical directional terms (e.g., dorsal/ventral, anterior/posterior, etc.) for animals as a whole (bipeds and quadrupeds).
Recently, I've been studying plant physiology, and I came to know that the upper surface of a leaf is…
MrAP
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Why is the opposite of plantar flexion called "dorsiflexion"?
Why is the action of flexing the foot so that the toes move anteriorly/superiorly (i.e. in the direction opposite that which they move during plantar flexion) described as "dorsiflexion?" In the same vein, why is the top surface of the foot called…
senshin
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