Questions tagged [anatomy]
The study of the structure of organisms and their parts.
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What is the smallest number of eyes that no animal has?
Lots of animals have no eyes at all. Among animals with eyes, the number is quite variable. Defining eyes broadly to include simple and complex eyes, I can think of examples of animals with any number ...
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Bivalve Respiration
Minor question: Is it "Mollusk" or "Mollusc"? I've encountered both spellings, and am unsure which is correct. For now, I'll use the "-k" spelling, but if anyone can ...
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how can a ganglion be defined as cluster of neuron bodies when it has interneurons?
Let alone the presynaptic button existing there as well, how is a whole interneuron existing there not contradict the definition ?
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Are there any sources of the approximate width of azhdarchid wing limbs?
Are there any sources with approximate calculations on how wide the front limbs of azhdarchid pterosaurs, especially hatzegopteryx should/would be? I've been searching but most of what I've found were ...
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Patterns of craniofacial topology
There are animals which are not directly related but have similar craniofacial topology.
For example: koala, donkey, mouse, turtle, parrot all have features seemingly belonging to same topology, ...
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What is the part between the eyebrow tail and above the eyelid called?
I need to know that anatomical name of the portion of the face between the eyebrow tail and the eyelid, as highlighted in red in the image below, as I need to refer to that particular area in writing ...
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Why are the ducts of pancreas lined with compound epithelium?
Most other places with compound epithelium are in contact with the outside world, and that of course makes sense. So why would a duct snugly placed inside our body need stratified epithelium? Is it to ...
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I learnt that anterior axillary folds are formed by pec maj but I can palpate and feel a hard tendon like structure
What is that hard tube like structure that I can feel in anterior axillary folds? I think it can’t be pec major because it’s tendon is bilaminar not like a tube? Is it suspension ligament formed by ...
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Is urethra a part of male accessory duct system?
In my textbook it is written that male accessory duct system constitutes the rete testis , vasa efferentia , epididymis and the vas deferens . Can urethra be also included here ?
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Sexual dimorphism of the Amphimachairodus genus of saber-toothed cats
Amphimachairodus is an extinct genus of particularly large saber-toothed cats.
Per Alan Turner and Mauricio Antón's The Big Cats and Their Fossil Relatives: An Illustrated Guide to Their Evolution and ...
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How did birds reduce their tail and fuse the last caudual vertebrae into a pygostyle?
I was just looking at the phylogeny of Avialae and saw that birds go from having long tails made up of many caudal vertebrae (ex: Archaeopteryx, Jixiangornis, Jeholornis) to ones with very few ...
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What determines the color of the air sac of a Portuguese man o' war?
I know that the Portuguese man o' war is a colonial organism composed of many "zooids", one of which is the pneumatophore, which essentially serves as a flotation device for the whole colony....
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Are the spikes or prongs in the frill of Ceratopsids considered horns?
Many Ceratopsids, mostly of the subfamily Centrosaurinae, have long spikes or prongs sticking out from the edge of the frill, most famously Styracosaurus, but also Diabloceratops and Rubeosaurus and ...
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Why are lymph nodes located where they are? [closed]
According to the National Cancer Institute, a subdivision of the National Institutes of Health, clusters of lymph nodes are found in the neck, underarm, chest, abdomen, and groin. Why are lymph nodes ...
user73773
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What is the earliest known animal that could run? [closed]
By "running" I mean a land gait that at one point has all propulsion limbs off the ground. Jumping, like a flea or a frog, is not running.
The earliest land vertebrates could not run, I ...
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Can arthropods rotate their joints?
I've been recently researching arthropod exoskeletons, and one thing I've seen more than once is that exoskeletons, due to how they work, only really allow for hinge joints. However, from seeing flies ...
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What is the difference between antennae and pedipalps?
I know insects, myriapods, and crustaceans, have "feelers" that get called antennae, while spiders and many other types of arachnids have pedipalps which seem to serve the same functions. ...
user59119
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How does Anabantoideis' labyrinth function? What does it look like?
Anabantoideis are fish with an organ that allows them to take oxygen directly from the air outside of water. However, I cannot find much on how this functions, nor can I find any clear image of what ...
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Scientific terms for front-brain, mid-brain and back-brain
I am looking for a (semi-) scientific way of phrasing "front part of brain" (part 1), "middle part of brain" (part 2) and "back part of brain" (part 3) as denoted in the ...
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Need help identifying vascular structures in brain matter
I am working on PET images of the brain. The neuro-oncologist I'm working with identified 2 large high-intensity regions as vascular structures. I've been meaning to ask what structures these are ...
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Which animal has the smallest percentage of their body mass made up of water?
It's a "well known" and interesting "fact" that the human body is made up of "mostly water". With percentages from 65% to 90% often being repeated as if they were exact ...
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What is the thickness of the mucous, submucosal, muscular and serous membranes of the stomach wall of a piglet aged 60-75 days? (Large White pig)
There is publicly available data on the thickness of the layers of the stomach wall of piglets aged no more than 20 days. But at an early age, the thickness of the layers of the stomach wall increases ...
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Are ganglion cells in the foveal avascular zone served by choroidal blood supply or diffusion from retinal layer capillary beds?
I am trying to determine which blood supply (choroidal or retinal) serves the retinal ganglion cells that respond to foveal cone stimulation. I know that the fovea is supplied by the choroid, but it ...
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How do we determine what we call "flexion" and what we call "extension"?
Question:
How did we determine which motion to call "flexion" and which to call "extension" with regard to the wrist and the neck?
Background:
Just to set the stage, I'm not asking ...
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Why porifera is classified to have an incomplete digestive system although it has no organs?
Why are we using the term "incomplete" for digestive system only? We could have also said that for circulatory system that it is either incomplete or present as a simple system. What I mean ...
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Is the fin of ray-finned fish live tissue or more similar to scales?
In ray-finned fishes, are what exactly are the fins made of? Is it modified skin, dead tissue like scale or nail on humans, or something completely different? Can the fin heal?
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Why is Heart Rate Recovery after exercise reasonably well described by a mono-exponential decay?
I have been measuring my heart rate recovery after exercise and I see that it can be fit reasonably well using a single exponential:
$HeartRate(t) = HR_{max} \times e^{-t/\tau} + HR_{resting}$
This ...
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Vertebrae looking bone found on beach in New Zealand
I found this bone on a beach in New Zealand. Does anybody have any idea which part of the body or which animal it’s from?
(click to enlarge)
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How fast does eyelid close when eyelash is triggered?
What is the reaction of blinking like when an unexpected piece of wood or something hits an eyelash and then an eyeball?
A piece of stone flew into my eyeball when we knocked a wall down, and it hit ...
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Aren't tortoise bones fused with the shell? How did this tortoise (in the post) survive without it?
I've just read this story about a tortoise that lost a good portion of its shell in a forest fire here in Brazil and got a 3D-printed prostheses.
Here's the picture of it:
The way it looks like, it ...
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Why is it possible to render fat if it's in cells?
To the casual onlooker, fat seems like a mass of yellow-white material, composed of lipids. Biologically speaking however, rather than being a large mass, it's actually divided among countless cells, ...
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Is the central sulcus the boundary between basal and alar derivatives?
The dorsal part of the nervous system typically gives rise to sensory structures, and the ventral part gives rise to motor structures. Because the central sulcus marks such a functional boundary, I ...
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Are there regularly spaced connections between caudate nucleus and putamen?
There are a number of images on the Web, most beautifully Visible Body's artwork, which show the caudate nucleus and putamen linked by regularly spaced connections across the barrier of the internal ...
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What is this insect wing, based on its vein pattern?
I've heard that it's possible to identify insect species uniquely based only on the vein patterns of their wings. Is this true? If so, what is this?
The image is taken from an unsolved Internet ...
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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 ...
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Is it true that oxygen levels in water limits fish size?
This answer says that breathing water is inefficient, and that may act as a limiter to the size of fish. I've heard this in a couple of other places as well, but cannot recall the sources. However, ...
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why dead mouse doesn't bleed when we cut their skin?
When we are pricked by a needle, we bleed nevertheless it's so small wound.
But when we do mouse anatomy, it doesn't bleed even if we cut their whole abdominal skin.
Other student asked about that, ...
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Do the nasal cilia move the particles trapped in the mucus out of the nose or down the throat? [closed]
Do the nasal cilia move the particles trapped in the mucus out of the nose or down the throat?
What is the direction of the pulse of the cilia? Is this changeable?
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Infant tissues, organs, body parts or reflexes in an adult organism
What is the phenomenon, when a normal useful tissue, organ, body part or an inborn reflex or instinct existed in the infant organism and normally should disappear or at least completely lose its ...
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The position of the macula in comparison to the blind spot
Which is located in a higher postion? Macula or blind spot?
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Animal species anatomy [closed]
https://en.wikipedia.org/wiki/Animal
Do all animal species have two lungs and two kidneys similar to human beings?
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Can a hinge joint technically allow rotatory motion?
Let's use a hinge joint and pivot joint as examples.
When talking about the difference between them in terms of movements permitted, I see that on any websites and textbooks, the term 'rotation' is ...
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Is there any ethnicity difference in average pupil size?
I have seen some articles claim African Americans have smaller average pupils than whites while Asians have larger pupils. Is it true?
link:
Y. Li, D. Huang; Pupil Size and Iris Thickness Difference ...
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Why exactly are the reflections of sunlight in this dragonfly's eye hexagonal?
I photographed a rather cooperative, large dragonfly today and after getting back to my desk and looking closer at the images I realized that the reflection of the Sun in its eyes produced large ...
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View and plane/section of neural tube
I have a question regarding the following image:
In my book, it states that this is a dorsal view which shows the formation of the neural tube. However, isn't this a caudal view of a transverse ...
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Why do dragonflies have these special little spots on their wings?
The wings of several kinds of dragonflies I've seen here in Taiwan all have an apparently special little pigmented spot near the ends of each wing.
Does this spot have a name and a function?
below x2: ...
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What exactly is "lateral septum"?
I came across the phrase lateral septum and I can't seem to find the precise definition online. Is it "the areas roughly to the right and the left of the septum pellucidum"? Or is it the ...
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What's the difference between the terms "muscle" and "muscle organ"?
Foundational Model of Anatomy distinguishes between Muscle organ and Muscle. What's the difference between the two?
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Can the shoulder bones grow after the growth plates have fused?
Body builders have broad shoulders. If one start lifting weights after one's growth plates have fused, can one still increase the width of one's shoulders? If yes, does that mean shoulder bones can ...
user60412
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In what ways does the number of legs affect an animal's functioning?
After much research, I've only been able to find specific examples of leg-number's impact on locomotion and dexterity (and/or object manipulation). I feel as though there must be other ways it has a ...
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