Questions tagged [anatomy]

The study of the structure of organisms and their parts.

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Ventricular Filling : Systole or Diastole?

As the Blood goes down from the Atrium to the Ventricles: The Tricuspid Valve ( Right Atrioventricular Valve) Bicuspid Valve (Mitral Valve ) The atrial pressure is INCREASES WHEN ATRIA ( THE ATRIA ...
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335 views

Is this claim about equine anatomy true?

While bumping through obscure corners of the Internet, I encountered the following image posted somewhere. The horse anus is a marvel of evolutionary biology. Like most mammals, rhythmic ...
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87 views

What does it mean for sodium and water reabsorption to be “coupled” in the nephron?

If sodium is transported across the tubule membrane down the concentration gradient established via the $Na^+$/$K^+$ exchanger via symport with glucose and antiport with hydrogen, and water is ...
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2k views

What are the max angles of human eyeball rotation?

How much can our eyeballs rotate towards the nose, away from it, towards the top and bottom?
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7k views

Why do eyes change colour after death?

Why exactly do eyes turn black when we die? (Or even change colour at all). The source of inspiration to this question is due to this video https://www.youtube.com/watch?v=6mNs_TcUyHc&t=627s (it's ...
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178 views

Are the transverse septum in sharks and the diaphragm in mammals homologous structures?

Are the transverse septum in sharks and the diaphragm in mammals homologous structures? I have searched on Google Scholar and Web of Science, but haven't found substantial evidence to prove or ...
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1answer
165 views

What are the small lumps in the mouth of the fish, and what is its function?

Today I was performing a fish head dissection to investigate the gas exchange process in biology. Then when I opened the mouth I noticed these small hard structures at the base, I assume they may be a ...
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1answer
292 views

How can paleontologists identify morphologically different fossils as members of the same species?

I recently saw a documentary about Tyrannosaurus rex, which detailed the growth stages of the dinosaur. Apparently, it underwent a huge growth spurt at around 14 years of age, growing into the massive ...
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66 views

Who were “Dawson and Wilson” (mentioned as authors of an embryonic postmortem examination method)?

A sentence from a Russian text I'm translating: Following the drug administration period, the pregnant animals were euthanized in order to examine the embryos using the method developed by Dawson ...
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1answer
74 views

Why did some animals evolve inward-slanted legs?

Something I noticed looking at reference images is some animals have legs that are slanted inward relative to the length of their body, like in the two images below. Why have animals evolved this ...
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57 views

How do emus/ostriches/rheas have their upper leg connected to the rest of their body?

I'm working on a model for educational graphics of an emu in conjunction with other information, but there aren't a lot of great reference images. The thing that's most unclear is how the upper leg ...
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124 views

Which word is used to indicate that a vessel is “blood-filled” during a necropsy?

I'm translating a necropsy report, and one sentence says: Синусоиды полнокровные. Портальные тракты сохранены, сосуды умеренно полнокровные. The sinusoids are plethoric. The portal tracts are ...
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94 views

Why do some insects constantly move their abdomens?

Why do some insects, such as wasps, constantly move their abdomens?
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505 views

Can you tell if a corpse was male or female by only examining its skull?

There are articles that says women have more rounded corner faces than men, than women noses are usually shorter, etc. But are those (and other features) tendencies or deterministic features that ...
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3answers
118 views

How do our sensory organs work automatically without our conscious effort? [closed]

I wonder how our different sensory organs (e.g., eyes, nose, ears, etc.) work automatically without our conscious efforts or without our command. We don't have to tell our eyes how to see, our ears ...
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3k views

Ipsilateral vs contralateral side of body

I know that the dorsal columns carry ipsilateral information. Is this fact relative to the dorsal column in question? If I want to talk about the right dorsal column, then the right side of the body ...
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1answer
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What is the function of the Hyoepiglottic ligament?

The hyoepiglottic ligament (ligamentum hyoepiglotticum) is an elastic band that connects the epiglottis to the hyoid bone. Although I can find information about the clinical significance of this ...
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2answers
1k views

What are the (correct) terms for these flagella-arrangements?

I came across the following diagrams depicting two kinds of arrangement of flagella over cells. Now according to my (very unreliable) school textbook, the arrangements are termed as: A - ...
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4answers
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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 ...
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2answers
4k views

Terminology for parts of the leg

Going out on a limb here (pun intended)...I'm writing a paper in which I need to refer to various sections of the human leg from upper thigh to knee to calf and ankle. However, "calf" covers a fairly ...
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29 views

Do the individual claws of a bear have names?

The question seems pretty self-explanatory (if perhaps a little odd). Anatomical names or colloquial names are both appreciated, especially the latter if they exist.
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28 views

I need a site for online courses

I need a site which has online courses for anatomy of limb and head and neck and also embryology, so far I have used www.coursera.org and it was really organized and helpful but unfortunately it does ...
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2answers
107 views

Is it possible for a man to survive around 20 bullets? [closed]

A man was shown being able to survive after around 20 bullets shot him in a movie. The bullet cover was fairly random, but anyway, is there any possible way for a person to survive 20 bullet shots? I'...
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748 views

How do you consider an organism to be a new species? [duplicate]

How do you consider an organism to be a new species? Can a new parthenogenetic organism be considered as a new species?
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237 views

Are there predefined implantation sites in mammalian uterus?

I do surgical embryo transfer of genetically modified (microinjected) mouse embryos (at 1 or 2 cell stage). As most of the constructs are new, we expect that it may affect birth rate. In case there ...
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227 views

How are neural pathways discovered?

I have seen the spinal cord and it's a white, soft, slippery cylinder that has a small diameter (about 25-30 milimeters). It absolutely doesn't have a macroscopocally reticular texture that would ...
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50 views

What is the biggest structure in nature for structural coloration?

I'm interested in the actual sizes behind structural coloration: I find it fascinating and I think it may have a couple very nice applications. The problem is I couldn't find anything but vague ...
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1answer
870 views

What purpose do the opening(s) serve in diapsid and synapsid skulls?

Did synapsid skulls evolve from diapsid skulls or vice versa? Aditionally, do birds have diapsid skulls? The research I have done has yielded some mixed results.
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Kidney transplant and adrenal glands

When a kidney is transplanted from a donor to a recepient does the surgery occur keeping the donor's adrenal gland intact over the kidney or is the kidney minus the adrenal gland over it transplanted ...
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1answer
27 views

How much smaller is the diffusivity of a molecule in the retina as opposed to the vitreous of the eye?

I'm interested in the diffusivity of macromolecules inside the mammalian retina, relative to the vitreous. For example is the diffusion coefficient for a macromolecule (protein, 50-150 kDa for ...
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2answers
7k views

Are tendons and ligaments classified under the muscular or bone system?

Are tendons and ligaments classified under the muscular system or the bone system? Basically they are not bones or muscles and that's why I have doubt.
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1answer
824 views

Animals with substantial five-fold symmetry besides starfish? Any land animals?

Animals with four, six and eight legs are widespread while the concept of seven legs (fictitious Heptapods) are the makings of amazing scifi short stories and blockbuster movies. Are starfish the ...
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63 views

What structures (i.e. organs) are suspended by tensile forces?

In several areas of biomechanical literature I have read, the concept of "tensegrity" has arisen. Definitions are as follows: “The integrity of a stable structure balanced by continuous structural ...
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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? ...
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929 views

Three foramen lying in one vertical plane

In the human skull we can see that 3 foramina named as supraorbital notch(foramen) , infraorbital foramen and mental foramen share a common vertical plane. Is there any surgical significance of for ...
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1answer
2k views

What is the name for the opening in the mouth for the nasal passages?

Is there a proper anatomical name for the opening in the soft palette where the nasal passages enter the mouth?
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1answer
102 views

Part of a fish outside the intestinal sac on the back?

I saw an expert Japanese chef fillet a mackerel (Scomber scombrus). He cut off the head and the whole intestinal sac came out with it as a single unit. Then he took the knife and scraped something ...
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1answer
443 views

Why do herring have fine bones

Most fish have largish bones which support the core muscles. Around the abdomen, they act as a sort of framework protecting the organs. With herring, the bones are really fine: almost thread like ...
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Can frogs see clearly under and above water?

If humans attempt to see underwater, the image is blurred due to refractive differences in air and water that disrupt the normal refractive effect of the lens in the eye. A diving mask overcomes this ...
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111 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 ...
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1answer
7k views

Coracoid vs. Coronoid - Etymology/Naming Choice?

The word coracoid (e.g., coracoid process of scapula) literally means "resembling a crow/raven" or "of the form of a crow/raven." In this case, I assume, resembling the hooked characteristic of a ...
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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 ...
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1answer
26k views

What is the difference between transverse section and longitudinal section? [closed]

Can anyone explain the difference between transverse and longitudinal section? Or are they the same?
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60 views

Prehistoric fossils [closed]

I have found very old seashell fossils (clamps) on a hill. They may be as old as a million years. Who can tell me how old they may be looking the pictures shown.
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1answer
6k 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 ...
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380 views

How is the Force of Contraction Applied to the Tendons by the Muscle's Individual Fibers?

Image and question have been updated for clarity! The image above is a side view of a semi-transparent skeletal muscle. The dark red lines represent individual fibers, the blue lines represent ...
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Correctly depicting spider anatomy

First off, my specific query: When depicting a spider - be it in a picture or in textual/verbal description - should the chelicerae be always be placed so that they project outwards from the ventral ...
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14k views

Why do we have more sweat glands in our palms?

Why is it that we have more sweat glands in areas such as the palms of our hands and the soles of our feet? I just learned that there are more there but I am curious as to why that is.
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For fish, does a bony skeleton have any advantages over a cartilage skeleton?

I have learned that two important lineages of fish are the bony fishes (Osteichthyes) and the cartilaginous fishes (Chondrichthyes). Many websites mention an advantage of the cartilaginous skeletons ...
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102 views

Phronima sedentaria anatomy

I would like to know how many appendages the arthropod Phronima sedentaria has, and how they are arranged. It's not hard to find picture references, but Phronima's transparency makes it difficult to ...