Questions tagged [anatomy]

The study of the structure of organisms and their parts.

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3
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1answer
2k 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 ...
3
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0answers
66 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 ...
83
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2answers
28k views

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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0answers
955 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?
0
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1answer
162 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 ...
2
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1answer
510 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 ...
9
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1answer
1k views

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 ...
6
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1answer
123 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 ...
4
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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 ...
36
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2answers
3k views

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
28k 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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0answers
63 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.
3
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1answer
8k 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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0answers
385 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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0answers
47 views

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 ...
8
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2answers
17k 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.
8
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1answer
4k views

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 ...
1
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1answer
108 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 ...
4
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1answer
58 views

What happens if the Nematode epidermis becomes damaged?

This animal has a hydrostatic skeleton which lets it move. If we damage the epidermis and fluids come out, can the nematode still move ?
2
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1answer
20k views

What is the cell matrix?

What is the matrix in the cell, and how does it connect cells together? I read about this in my textbook. I know that a matrix is the material (or tissue) that connects other cells together. My ...
3
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2answers
76 views

Isolating the vasculature of an organ?

Is there a chemical or process that would dissolve or remove all other tissues in an organ and leave all the vasculature intact? I am planning to make a shelf display of the blood vessels in the heart ...
2
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0answers
43 views

Does human skeletal muscle fascia grow new additional collagen in response to increases in skeletal muscle size?

For example, if a human skeletal muscle is growing repeatedly due to periodic weightlifting, does the fascia eventually respond to the increasing volume by growing more quantities of collagen or other ...
2
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0answers
1k views

Does the humeroradial joint move medially/laterally?

The humeroradial joint is a ball-and-socket joint that, if unrestricted, would allow for movement around all possible axes. However (as succinctly stated from Wikipedia): the annular ligament, by ...
13
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2answers
6k views

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 ...
1
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1answer
117 views

Do mucous membranes surround visceral organs?

Wikipedia claims that: A mucous membrane or mucosa is a membrane that lines various cavities in the body and surrounds internal organs. The first part of that sentence is clearly accurate, but I ...
11
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1answer
92k views

Dorsal vs Posterior and Ventral vs Anterior

From prior reading, I thought that Dorsal is the same as Posterior and Ventral is the same as Anterior. However, when I checked in google images for these anatomical terms for a horse (just to ...
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2answers
260 views

Cells in tissues

Tissue (biology): In biology, tissue is a cellular organizational level intermediate between cells and a complete organ. A tissue is an ensemble of similar cells from the same origin that together ...
3
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1answer
95 views

How does horse extract the energy to needs from a relatively small digestive system?

Recently I saw Inside nature's gaints episode on horse, and was fascinated about its internal organisation. And my question is that they have a very large lungs to accommodate, but a relatively ...
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1answer
1k views

Are tergo-sternal muscles of cockroach involved in blood circulation?

Tergosternal muscles help in the blood circulation in a cockroach as well as in movement of the wings for flying. I came across a question that claims that these muscles are used in blood circulation ...
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0answers
42 views

Is the enteric nervous system found only in vertebrates?

The enteric nervous system is distinguished by being autonomous from the central nervous system and capable of independent action, such as the peristaltic reflex. For this reason the the intestines ...
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0answers
837 views

What makes the hepatic portal vein unique?

What makes the hepatic portal vein unique?, is it because it begins and ends with capillaries or because it carries digested food.
7
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1answer
5k views

What is the rest state for eyelids - Open or Closed?

If one were to not apply any efforts on the eyelid muscles, will they remain open or closed? In movies when we see a person die, either case could happen - their eyelids could be open or closed when ...
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0answers
167 views

Has any animal ever had a rotating part?

Outside of microscopic structures (I'm thinking of a flagellum, which I think is a true motor) has any animal evolved a part that continually rotates compared to the rest of its body?
3
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1answer
553 views

Why is there debate about thymus being an endocrine gland?

I read on my textbook that there is debate about whether thymus is an endocrine gland. But they do have glandular cells no? Is producing T Cells the only point for thinking it not as a part of ...
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0answers
227 views

Can human eys/the brain be trained to see with bidirectional monocular vision?

Most people have a dominant eye, and while it uses its non-dominant eye in tandem with the dominant eye most of the time, the brain, being an expert in eliminating redunant information, ignores the ...
3
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1answer
1k views

Is the male bee's penis homologous to the female bee's stinger?

Considering that when a bee stings it loses its stinger and dies, this is similar to the male drone losing its penis and dying after copulation. It also seems similar that each event basically rips ...
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0answers
113 views

The first species having circle of Willis (circulus arteriosus cerebri)?

I know mammals are not the only species that have this anatomical unit (i.e. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982101/). But I was wondering what was the first species that had a similar ...
9
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2answers
20k views

What is the anatomical term for a two jointed leg?

Allow me to apologize in advance for the layman's terminology. I'm wondering what the anatomical term for a cat- or a goat-style hind leg is. Cats, goats, t-rexes, and many many other animals don't ...
11
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0answers
399 views

Anatomical Angle Made by the Fingers of an Extended Palm

Does the angle made by the fingers (excluding the thumb) of an extended palm (as shown in the figure below) have a name (such as the Lovibond or Cobb angle, for instance) ? I have already checked ...
27
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1answer
25k views

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 ...
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0answers
218 views

What reason that land vertebrate evolve keratin while other animal use chitin

I don't know why there are evolutionary split in material. Why we evolve keratin and lose chitin? What the advantage and disadvantage for each material? Is it because the size or there are other ...
1
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1answer
169 views

Accommodation mechanism. [closed]

Can anyone explain how contraction of the ciliary muscles causes relaxation of the zonules? Please explain it anatomically i.e. the attachments of ciliary muscles and its relation with the ...
7
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1answer
21k views

Do male humans have a mons pubis?

Wikipedia writes: In human anatomy, and in mammals in general, the mons pubis (also known simply as the mons, and known specifically in females as the mons Venus or mons veneris), is a rounded mass ...
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0answers
3k views

Do any non-human species have packed abs?

The classic "six-pack abs" in humans is due to tendons stretched across the abdominal muscles and low body fat. Do any other animals have a similar arrangement of tendons that could result in visible "...
2
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0answers
86 views

What is the circulation that allows for nutrient absorption and excrete of metabolic wastes in humans? [closed]

Pulmonary veins carry oxygenated blood from lungs to heart, while pulmonary arteries carry deoxygenated/CO2 rich blood from heart to lungs. On the other hand, systemic arteries carry oxygen-rich blood ...
1
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1answer
323 views

Why do some drugs require you to take them in an "upright position"?

A friend of mine was taking the supplement Metamucil and on the container it says to take in an "upright position." Why would this be necessary? Doesn't your digestive system push food/liquid ...
8
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1answer
13k views

Can defibrillation be done with a car battery?

Can successful defibrillation be done with a car battery? Is it POSSIBLE for this to work? Let's say you are stuck on a very remote place and something happens to someone... Moreover, can you jump ...
2
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1answer
2k views

What does it mean for muscles origins and insertions to be the other way around in the right than left limb?

Herbert Srebnik writes in Concepts in Anatomy: In the right limb, the muscle's origin is proximal to the joint and the insertion is distal to it. In the left limb, the muscle's origin is distal ...
2
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1answer
167 views

Does size matter?

As I compare the morphologic differences between mouse models and the human disease for which they are analogous, I have become interested in what difference interspecies size has on molecular ...