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Questions tagged [anatomy]

The study of the structure of organisms and their parts.

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4 votes
2 answers
358 views

True anatomical/physiological explanation for "metaphysis" etymology

The anatomy textbook1 I use for my students states that the prefix meta- means "between:" The metaphyses (me-TAF-i-sez; meta = between; singular is metaphysis) are the regions between the diaphysis ...
0 votes
0 answers
58 views

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 ...
0 votes
0 answers
73 views

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, ...
1 vote
2 answers
120 views

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 ...
22 votes
5 answers
10k views

How did the cardiovascular system evolve?

How has evolution created our blood, lungs and the heart? We can't exist without blood, which transports the oxygen to all areas of our body. However, the blood needs a lung, which gives it the ...
1 vote
1 answer
55 views

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 ...
0 votes
0 answers
26 views

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 ...
0 votes
0 answers
14 views

Can the instantaneous center of rotation of a vertebrae be mathematically determined for flexion of lumbar?

I am starting to learn spinal anatomy and I want to determine the Instantaneous axes of rotation (IAR) of individual vertebrae. I have referred many research papers but haven't come across any useful ...
0 votes
0 answers
23 views

What are all the possible abnormalities in our body that will result in ataxia?

So I know that ataxia is caused by loss of proprioception.I only know that dorsal column medial leminiscal pathway carries proprioceptive fibre to the cerebellum.So in theory damage to either this ...
0 votes
1 answer
96 views

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 ?
3 votes
0 answers
85 views

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 ...
2 votes
0 answers
28 views

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 ...
3 votes
0 answers
84 views

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....
1 vote
0 answers
18 views

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 ...
7 votes
1 answer
13k views

How many abdominal sclerites would be there in a cockroach?

Every tegmina of a cockroach has sclerites which are analogous to the bones of humans. Every abdominal segment of cockroach consists of two lateral sclerite plates called pleura along with a dorsal ...
4 votes
0 answers
116 views

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 ...
-2 votes
1 answer
309 views

How can a joint extend or flex?

The idea of a joint flexing or extending doesn't make sense to me, I can see how a leg or an arm might extend or flex but how does a joint extend or flex ? "The hip joint is most stable when it is ...
3 votes
0 answers
63 views

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 ...
3 votes
0 answers
36 views

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 ...
4 votes
2 answers
7k 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
0 answers
149 views

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. ...
-1 votes
2 answers
79 views

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 ...
3 votes
0 answers
109 views

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 ...
6 votes
2 answers
5k views

Why does sympathetic activity constrict pulmonary vessels?

I don't know understand why sympathetic stimulation constricts pulmonary vessels? I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need ...
2 votes
1 answer
83 views

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 ...
5 votes
1 answer
9k views

How are arms different from legs?

How are arms and legs defined physiologically? For example, we say humans have two arms and two legs, while cats have four legs, and some monkeys (appear) to have four arms (although I guess they ...
5 votes
1 answer
2k views

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 ...
2 votes
0 answers
69 views

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 ...
3 votes
0 answers
31 views

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 ...
1 vote
0 answers
129 views

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 ...
13 votes
5 answers
22k views

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 ...
0 votes
1 answer
414 views

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 ...
4 votes
1 answer
89 views

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?
4 votes
1 answer
11k views

Explanation for hyenas asymmetric legs length

Hyenas seem to have disproportionately short hind legs. It may be the opposite, maybe the front ones lengthened to raise their heads even higher than their already long necks do. In any case, this ...
5 votes
2 answers
587 views

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 ...
0 votes
0 answers
625 views

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)
3 votes
1 answer
96 views

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 ...
-4 votes
1 answer
155 views

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 ...
2 votes
0 answers
85 views

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 ...
-1 votes
1 answer
837 views

Why rectus abdominis is not proximal muscle?

I am thinking this picture which shows proximal muscles. Why for instance pectoralis major, subclavius and rectus abdominalis are not included in proximal muscles?
3 votes
0 answers
69 views

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, ...
5 votes
1 answer
238 views

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 ...
4 votes
0 answers
108 views

Medical terminology for asymmetrically-shaped paired body parts?

Some people have different sized feet [source], a limb that is slightly longer than the contralateral (on other side of the body) limb [source], or other instances of paired body parts being different ...
34 votes
8 answers
10k views

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 ...
2 votes
0 answers
59 views

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, ...
0 votes
1 answer
625 views

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, ...
0 votes
2 answers
419 views

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?
1 vote
1 answer
39 views

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 ...
6 votes
1 answer
160 views

When is an anatomic entity named "laterale" vs. "lateralis"?

I'm trying to learn the latin names of anatomical entities and I have a hard time remembering whether it's "Os cuneiforme laterale" or "Os cuneiforme lateralis". In that case it's "laterale". But in ...
-1 votes
2 answers
656 views

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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