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Questions tagged [muscles]

The contractile tissue of animals derived from the mesodermal layer of embryonic germ cells.

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How correlated are the lengths of tendons in different part of a human body?

How correlated are the lengths of tendons in different part of a human body? E.g., if the we consider two humans, A, and B. Human A has a patellar tendon of length 2 cm, and human B has a patellar ...
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Does loss of dopaminergic neurons totally eliminate voluntary muscular control?

Breathing is a function that is not only autonomic, but can also be temporarily overridden and placed under voluntary control. In fact, you are now breathing manually. Now, suppose that someone has ...
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Why proximal muscle weakness is seen earlier than distal muscle weakness in Dermatomyositis?

It is said that in dermatomyositis(DM) , proximal muscle weakness is seen earlier than distal muscle weakness. It is also said that , DM is due to damage to small blood vessels contributing to muscle ...
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For each movement performed by both the gluteus minimus and medius, what percentage of the movement do the gluteus minimus and medius account for?

From what I read on Wikipedia, all functions of the gluteus minimus are mirrored by the gluteus medius. Additionally, the gluteus medius is larger than the gluteus minimus (see comparative images here)...
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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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Why some muscles have more tendons than others?

Very interesting examples to me are Trapezius or Latissimus - they both have places with more tendons than muscles. Taking into account that now they contract weaker and slower with all these tendons, ...
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Apart from nerve cells and muscle cells, what types of cells do not undergo mitosis in adult man?

Neurons and muscle cells in adult humans do not have the ability to divide by mitosis, so they can not repair themselves and their cell cycle remains in the interphase. I’m looking for more cells with ...
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What muscle models describe “strengthening”?

As I understand it, muscles grow in strength when they are subjected to loads larger than they are used to handling. This causes local damage to the muscles cells and, through an immune system ...
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How does isometric contraction work?

What exactly happens to myosin during isometric contraction? I suspect that either myosin heads just "freeze" in the middle of crossbridge cycle, or go through full crossbridge cycles repeatedly at ...
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Do cells in healing ligaments or tendons have deformation processes? If so, what are they?

I am trying to better understand how non-muscle tissue in the muscuoloskeletal system heals. Specifically, I am interested in how ligaments or tendons heal once torn. I read the following text: ...
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Can one assess muscle strength through imaging (e.g., MRI)? If so, though which type of imaging and how accurate is it?

Can one assess muscle strength through imaging (e.g., MRI)? If so, though which type of imaging and how accurate is it? On How does muscle size relate to strength?, I read this answer from Moses (...
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Is there any stem cell or biogel method that exist for muscle and tendon lengthening?

Is there any stem cell or biogel method that exist for muscle and tendon lengthening? It is known that height surgery is limit to six inches with two surgeries and three inches each, it is also true ...
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How does shoulder rotation work when the arm is overhead?

Anatomy references state that the humerus is externally rotated by infraspinatus, and teres minor, and internally rotated by subscapularis. All the illustrations I can find of these muscles have the ...
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Where does the gluteus medius attach to the greater trochanter compared to the gluteus minimus attachment?

Where does the gluteus medius attach to the greater trochanter of the femur compared to the gluteus minimus attachment? Is it above, below, next to it, etc.? Ideally I'd like to know the distance as ...
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Does estrogen increase muscular growth in females?

Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of ...
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Are there certain symmetric-pair muscles that are slightly bigger and NOT due to handedness?

Ok, hear me out, I was just thinking about an article in Nature I read in the past titled "Scrotal asymmetry in man and in ancient sculpture"$^{\dagger}$ and more recently an entire medical textbook ...
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Is “muscular attachment” synonymous to tendon? (when talking about the insertion of glutei medius and minimus to greater trochanter of the femur)

I have read the following two terms in an MRI report (both points refer to the insertion of gluteus medius/minimus to greater trochanter of the femur): mild degeneration of the muscular attachment ...
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What is a myotube?

If I understand correctly, the following images show the main components in a human skeletal muscle: From Life: The Science of Biology: From Human Physiology/The Muscular System in wikibooks: ...
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Can disorders involving involuntary muscle twitches and spasms have a hypertrophic and increased residual muscle tension effect?

Meaning disorders specifically like myokymia, myoclonus (positive and negative) and fasciculations. From the section of the literature I've seen, sometimes passing mentions are made when the disorder ...
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What is the connection between exercise and muscle growth

From a physiological perspective, all that is done during exercise is the expending of energy in the form of ATP to fuel muscle contraction and extension. When I looked up why muscle grow due to ...
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Mechanism of redirected blood

I've read several fitness articles mentioning redirected blood flow to muscles that are in use. However, they never mention how it works. Is it local and specific to the muscles in use? Or, for ...
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Does constant pressure cause muscle atrophy, and if so, why?

I read on https://en.wikipedia.org/w/index.php?title=Gluteal_muscles&oldid=876760828#Clinical_significance: Sitting for long periods can lead to the gluteal muscles atrophying through constant ...
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Difference in timescale of tissue movement vs cellular differentiation

I would like to better understand the difference in the timescales that cells seem to function. For example, how is it that muscle cells can move within seconds or less under stimuli such as hormones ...
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Strongest muscle of Human Body

Which is the strongest muscle of human body ? Confusion b/w Masseter muscle (Muscle of Jaw) and Tongue and Muscle of Heart and Muscle of Uterus.
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What is the tensile strength of muscle?

So I am looking at determining the pressure needed to impale a person with an object of a given size and shape. To figure this out, I believe I need to know the tensile strength of skin, bone, and ...
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Can the heart and other muscles function without creatine/phosphocreatine?

Skeletal muscles in the body have a small reserve of ATP. During the first few seconds after contraction, phosphocreatine is used by the enzyme creatine kinase in order to phosphorylate ADP to ATP ...
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Why do smaller mammals move intermittently?

I was watching a nice little video on youtube but couldn't help but notice how snappy smaller animals such as rats and chipmunks move. By snappy I mean how the animal moves in almost discrete states ...
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Why is the ingestion of salt and water beneficial to muscle cramp

According to Wikipedia, muscle cramps are caused by the inability of myosin fibers to break free from the actin filaments during contraction, resulting in a prolonged contraction. A lack of ATP would ...
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Are there specific theories as to what causes cold[-water] muscle cramps?

The field of what might cause cramps is quite contested with a lot of controversy around the heat/dehydration cramps, but I find it surprising that no specific theories appear to have been proposed (...
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Can muscles work as brakes?

When I walk downhill I lose potential energy. If I descend 100m in, say, 10 minutes I lose potential energy at a rate of about 114J/s (114W). Where does the energy go? Not into kinetic energy ...
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How much energy can one muscle contraction deliver?

How much energy is available in a single muscle contraction? I'm guessing the correct units are J/kg, but I'm open to more correct units. I'm looking for work done, not total energy dissipated (not ...
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How fast can muscle fibers relax

I can find a great deal of information about how muscles contract, and how we divide them up into fast twitch and slow twitch and so forth. However, I can't seem to find anything on how fast a muscle ...
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Are there known counterexamples to Hennman's size principle for muscle unit recruitment?

It is known that generally muscle units are recruited from small to large, and that typically also means slow to fast twitch. This principle is called Hennman's size principle. I've seen many ...
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How is breathing involuntary if the muscles that control it are skeletal?

How is breathing involuntary if the muscles that control it are skeletal? Breathing is involuntary. However, the muscles that control it are skeletal: intercostal muscles and the diaphragm. Are there ...
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Contracting mouth muscles as reaction to taking in specific food items

When eating very specific food items, especially confectionery like (salty) liquorice, (it feels as if) the muscles of my mouth contract, right when it hits my tongue. Does anyone know why this ...
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Skeletal muscle has got many many peripheral nuclei. What does “peripheral” mean here?

Cardiac muscle has got a central nucleus similar to smooth muscle, but skeletal muscle you may recall has got many many peripheral nuclei. What does "peripheral" mean here?
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Etymology of eccentric/concentric contractions

I was wondering if anyone knew why the terms eccentric and concentric were chosen to refer to lengthening and shortening muscle contractions? The basic etymology of the words are to do with ...
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What is official term for contraction induced muscle “vibration”?

I can activate my tensor tympani muscles at will, it makes me hear rumbling bass sound becose the muscles "shiver / "vibrate" when contracted. Also when I put cleched fist to my ear I can hear it too. ...
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When muscles contract is the process similar to how non-newtonian fluids react?

I'm trying to understand how muscles contraction/tension works but getting loss in on the cellular level. From my understanding, when muscle tissue need to contract, the cells are flooded with calcium?...
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Can acetylcholine leak away from the synapse and cause spasms?

I am currently studying Pharmacology and a question came to mind. We know that Acetylcholine is used as a neurotransmitter in the neuromuscular junction, both Sympathetic as Parasympathetic, but as I ...
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How efficiently does the human body convert the energy stored in fat into kinetic energy?

I read that one gram fat contains 9 kcal energy. There are many tables around claiming that x type of exercise for t duration ...
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How many muscles work for a smile and how many when you are sad? [closed]

Muscles works in both cases but it’s seems difficult to understand that how they work
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Are there biological ratchet cycles that are small in number?

I recently came across the strange factoid that all animals that can jump do so to roughly the same height (within an order of magnitude). The argument was that the work done by muscles in a single ...
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does being battered build muscle?

My crude understanding of how people normally go about building muscle is something like this following 2 step process: 1) a person can lift weights (for example), which tears muscle and stimulates ...
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What are potential side effects of myostatin inhibitors?

Myostatin inhibitors, which are being developed to treat muscle wasting diseases like muscular dystrophy, are likely to be abused by athletes. What are the potential long-term side-effects of taking a ...
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Myoglobin in meat

When looking at the reason why some meat is white and the rest is red, I found out it is down to the levels of myoglobin as higher levels of myoglobin are found in "slow twitch" muscles. I have also ...
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why do we tighten out muscles against cold?

When I'm in shower and I want to open the cold water on myself suddenly I make my muscles so tight before I open the water and that helps so much in being able to handle the shock. Why does tightening ...
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Do muscles and connective tissue have different types of pain receptors?

I assume that muscles have pain receptors ("nociceptors"?) that fire when the muscle is under excessive strain or even tears or becomes injured. I also assume that similar pain receptors exist for ...