Questions tagged [muscles]

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

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Could the protein dystrophin be artificially synthesised?

Could the protein dystrophin be artificially synthesised and if so could patients with DMD (Duchenne Muscular Dystrophy) benefit from it? //Now I don't have much scientific background other than a ...
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43 views

How strong of an electric field is dangerous to adult humans?

Given that "a potential difference is introduced over the membrane, the associated electric field induces a conformational strong in the potassium channel" is required for our muscles to move, how ...
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100 views

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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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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examples of transitional fossils showing development of internal skeleton

What fossils exist that show the development of skeletons, and muscles attached to bones?
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How does use an action potential from innervation selectively modify tropomyosin over time?

Within a myofibril, the myofilaments move past one another to product muscle contraction if and only if the actin binding sites are exposed to the myosin by locally removing the tropomyosin by binding ...
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How can myoglobin be responsible for the red color of meat if it is located in the cytoplasm?

How can myoglobin be responsible for the red color of meat if it is located in the cytoplasm, as the visible part of muscle cells is the membrane (at least as I believe)? Sources: https://en....
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brain and fingers movement theorie

I heard somewhere that when we want to do a repetitive movement of one finger (ex the index) . Our brain (in a very crude way) sends a first message to move all the fingers, and then a second message ...
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Typical firing patterns of (some) motor neurons

Since it is not so easy to imagine and visualize the behaviour of the muscles in the fingers, hand, and arm of a violinist performing a fast and accentuated trill vs. a slow and soft vibrato, I try to ...
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Muscle involved in carrying load on head

I have seen people carrying heavy load on their head especially in 3rd world countries, does carrying on head any benefit or harm, which muscle get strengthen in doing it?
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What is the point in the Neuromuscular Junction?

Surely a direct connection (i.e. an electrical synapse) between motor neurone and the sarcolemma would allow for much faster neuromuscular transmission? It is my understanding that chemical synapses ...
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458 views

Function of Smooth Muscles in the skin

I understand that the overall function is voluntary movement, but is it the same in the skin? Is the main function in the skin movement or is there a greater function? Could anyone could provide this ...
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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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Under which circumstances does muscle hyperplasia happen in humans?

What circumstances allow humans to have muscle hyperplasia in the prenatal and immediately postnatal period that doesn't exist later? Is it about specific hormones that follow through our veins?
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Do eye's muscle share the same nerve?

When I try to rotate my eye, both of my eyes will rotate the same amount and in the same direction (obviously). I'm wondering if it is possible to control each eye separately. I've never seen anyone ...
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Is an adaptation against impact of fall a factor in babies' bones' structure?

Obviously, babies' bones need to be flexible to get through the pelvic bone. But is that the only reason? Could it be that as babies aren't able to maintain stability, they need bones less prone to ...
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How did the largest/longest dinosaurs hold their head and necks up?

After seeing the images in the articles shown below, I am having a tough time understanding the mechanics of how these incredibly long and heavy necks can be supported outstretched like this. A rigid ...
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Why fingers in human fists get folded in absence of neural stimuli?

Background: I noticed that the fingers in our fist tend to get folded in absence of neural stimuli. The same thing happens in case of our hands and legs. Question: What is the mechanism behind this ...
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When a muscle contracts, does it store potential energy like a spring that is released upon relaxation?

A colleague of mine who mainly focuses on clinical chiropractic work claimed recently in a book he wrote that muscles in the pelvic floor have "elastic recoil." What he means by this is that a ...
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134 views

In myosin II are regulatory and essential light chains calcium binding proteins or sites of phosphorylation?

According to my medical physiology by Rhodes and Bell their description is as follows: the essential light chain is necessary for myosin stability, and the other chain called the regulatory light ...
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What chemical conversions are involved , and what's the name for the process, when the muscles use lactate as an energy source?

I understand that muscles do anaerobic metabolism, specifically, "lactic acid fermentation", which I understand produces lactate. I'm not asking about that process. What chemical conversions are ...
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What do we mean when we say that a muscle fiber contracts strongly?

Sounds dumb but anyway, i heard that superfast fibers contract more strongly than fast twitch fibers. And i never thought of muscle contraction as something that has a magnitude (i thought of it as "1 ...
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Why do hand/fore-arm muscles “lock up” after very high-powered effort?

Inspired from Why does it hurt the next day after doing significant exercise? with its excellent answer: In climbing, you can put tremendous load on the hand/fore-arm muscles (specifically, flexor ...
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Why does it hurt the next day after doing significant exercise?

I think this is a fairly common observation that if one does some significant amount of exercise, he/she may feel alright for the rest of the day, but it generally hurts bad the next day. Why is this ...
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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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Energy efficiency of muscles and animals as a whole

When human or animal do some work, they use energy from their food. What is known about overall efficiency of this process? Say a horse is turning a winch and does 10,000 kJ of work. How much more ...
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Limit of muscle atrophy [closed]

I read that lack of action leads to muscle atrophy , I experienced same when I had a cast for hand fracture. So how far this atrophy go, who decides minimum size of muscle due to lack of activity, for ...
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Lengthening muscles not good from evolutional perspective? Why do we do it with explicit stretching?

Stretching has many advantages, among other things it helps us to be flexible in our movement (which is an advantage?!). But why do we need to actively stretch, it seems that the body wants to ...
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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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Need / consumption of magnesium

Does doing sports makes a human require more magnesium and – if any – how strong is this effect? Do athletes take magnesium supplements (e.g. pills of magnesium carbonate) because they build muscles ...
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Bone fracture cause [closed]

I had bone fracture twice in the same arm. So I had first bone fracture in right forearm with 45 degree break on two bones, after 3 months of that fracture while I was climbing a slope I fell and I ...
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The link between muscle mass and muscle strength and how to train for each [closed]

I'm getting into my fitness and am beginning to see an increase in muscle mass. However, I look at people like Bruce Lee, Elliott Hulse, Mohammad Ali and Wim Hof who are capable of incredible strength ...
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Does the speed of muscle contraction within a single sarcomere differ between people?

Of course the number of muscle cells can be different person to person. But within a single sarcomere, are we all the same? Would the frequency of the protein motor binding and release cycle ...
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683 views

Are there genetic causes underlying the difference in circumference of the upper arm and foream?

Is there any genetic reason for the difference in size between the upper arm and lower arm (i.e., the forearm)? In most women, it seems that the upper arm is larger in circumference than the forearm. ...
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How to contract sternocleidomastoid muscle by thought?

If I do not turn my head, how can I contract ( or tighten) the sternocleidomastoid muscle ( like we can intensely tighten muscle in limbs)?
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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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Why does lactate build up prevent a further increase in the speed of an athlete?

This question was triggered by an exam question that I was doing on the following paper (Q2 part (b)(i)): http://qualifications.pearson.com/content/dam/pdf/A%20Level/Biology/2013/Exam%20materials/...
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Why are successful human rock climbers so dissimilar to Hominidae primates who spend extended time periods climbing? [closed]

In rock climbing, the sport considers the Ape Index when evaluating the factors critical for success. However, the majority of successful climbers are lithe and slim with less than 8% body fat. As ...
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What is coffee effect on muscles ? On sport performances?

Since coffee is a vaso-restrictor does it have any impact on sport performances ? I mean does it go against natural way the body works (sending more blood to muscles due to the increasing needs) or ...
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What makes delayed onset muscle soreness stop occurring?

If someone lifts weights or takes a long jog after not doing it for a while, they can experience delayed onset muscle soreness (DOMS). However, when they return to the same exercise days afterwards, ...
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What is difference between High quality and low quality proteins [closed]

I have seen in news that some bodybuilder died of taking steroids; when I went through details I learned that "low quality proteins" contributed to their death. I have studied about linkages in ...
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How can skeletal muscles in the human body be modeled as levers? [closed]

From what I understand, human arms can be thought of as third class levers, so that the distance from your elbow to the place where the muscle attaches is effectively the distance to the fulcrum, so ...
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6k views

Location of t tubule in muscle

Why do mammalian skeletal muscles have t-tubules at the junction of the anisotropic and isotropic band, whereas non-mammalian muscles and cardiac muscles have it at Z-line? What could have been the ...
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794 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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Bending your little finger without bending ring finger

It is possible to bend each finger without bending any other, except one for most people. It is more difficult for the ring finger, but when I try to bend my little finger independently my ring finger ...
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323 views

What is the difference between a “semi-contracted” muscle and a “contracted” muscle?

I read on http://www.spine-health.com/glossary/muscle-tension: Muscle tension refers to the condition in which muscles of the body remain semi-contracted for an extended period. What is the ...
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What is the difference between muscle tension and muscle tightness?

Is there any difference between muscle tension and muscle tightness? I want to study the relation between forearm muscles tightness/tension and tendinopathy (specifically, medial and lateral ...
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How do our muscles get tired?

I know one of the main reason why our muscles get tired is because there is too much lactic acid, but how does this lactic acid negatively affect the action of myosin on actin?
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Muscle contraction/extension percentage during normal ranges of motion

What is the typical percentage range/limits of extension/contraction during normal ranges of motions for muscles? Assuming a rest length in a typical relaxed state. I'm mostly interested in humans ...
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2k views

8 abdominal muscles but 10 pack

Simple question, how is it possible that there are people who appear to have 10 pack abdominal muscles while the human body has only eight?