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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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4
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2answers
2k views

How does the muscle return to its resting state after muscle contraction?

I know that when ADP binds to the myosin head, it moves along and as it does so, it releases the ADP. The ATP attaches to the myosin head and releases the myosin head from the actin filament. Then the ...
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1answer
1k views

What causes humans to be physically weak compared to animals like gorillas?

Animals like gorillas seem to have a physical fitness and muscle mass that don't depend as strongly on how much exercise they get, compared to humans. E.g. gorillas living in the wild sleep and rest a ...
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1answer
11k views

What is the difference between muscle fascicle and muscle bundle?

In the photo above (given by Bio teacher), the muscle bundle is shown to be as a bundle of fascicles, but in most web definitions I've seen, the two terms are used interchangeably. What is the correct ...
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6k views

Abdominal muscles during inspiration/inhalation

During inspiration I am aware that the diaphragm and the external intercostal muscles contract, thus increasing the volume of the thoracic cavity. However, I read on my textbook that during ...
3
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0answers
155 views

How is recruitment of multiunit smooth muscle cells fine tuned if they are innervated by varicosities?

In my physiology textbook (Silverthorn) and on wikipedia it says that: Multiunit smooth muscle tissues innervate individual cells; as such, they allow for fine control and gradual responses, much ...
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1answer
2k views

What causes spontaneous muscle twitches?

Sometimes a small region of my body starts shaking, without any reason and then stops abruptly. Apparently this is a common phenomenon (source: NIH). I researched its cause for a bit and came to know ...
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1answer
2k views

What happens when our muscle tense? [closed]

Is the tensing of muscles equivalent to stretching them? I am trying to understand what tensing of the muscles means.
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1answer
7k views

Doesn't the sarcomere contract during isometric contraction?

During muscle contraction, the lenght of the sarcomere changes, length of myocyte changes and so does the length of muscle. However, if the length of muscle is not changing length as in isometric ...
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0answers
94 views

How is the side-polarity of the myosin filament in myofibril maintained?

If myosin molecules are the properly oriented relative to their position in the the myosin filaments, the sarcomere is not functional. But how is the orientation of the myosin molecules determined? ...
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2answers
10k views

Why we shiver/tremble/shake while performing some work which requires high accuracy?

Shivering when nervous or anxious is a common thing. But, shivering or trembling sometimes also occurs when we are performing a work which requires high accuracy. In such case, our whole body doesn't ...
8
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1answer
5k views

Why do my muscles move slowly when cold?

When my hands are cold, e.g. outside in the winter with no gloves for a while, their muscles begin to move slowly (assume I'm otherwise comfortably warm, e.g. dressed well but gloveless). I don't ...
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0answers
38 views

Does physical exercise of a specific part affect muscles in the other parts of the body?

There is a theory among bodybuilders, that is, if you train big muscle groups (e.g. legs, chest), it will increase the overall growth of muscles all over the body; the trained muscle will release ...
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0answers
41 views

How are muscle fibre size and oxygen consumption related?

Does anyone know of a paper which correlates the muscle fibre size to oxygen consumption in mammals? I am trying to find a correlation between muscle fibre type, size and (absolute and specific) ...
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0answers
52 views

What are the metabolic consequences of negative mechanical work in muscle contractions?

When a muscle contracts while it shortens (concentric), it consumes ATP I believe primarily due to cross-bridge shortening to remove the myosin head from it's attached state. However, when a muscle ...
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0answers
70 views

Why do workouts cause your muscles to feel heavy?

I know that muscle activity causes your muscles to build up lactic acid. Is this the specific reason that your muscles begin to feel heavy? How does this relate to the healing or inflammation process ...
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0answers
728 views

Acetylcholine and muscles- excitatory or inhibitory? (muscle atonia and myasthenia gravis)

I have heard that acetylcholine can be excitatory or inhibitory, but I am confused as to which it is when it comes to muscles. On the one hand, I believe that muscle atonia during REM sleep is ...
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1answer
573 views

How do crocodiles stay fit?

My 8 year old son asked me a question I could not answer (and Google, at least in so far as we tried, was no help either). We were watching a documentary about Salt Water Crocodiles in Northern ...
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1answer
106 views

What differences in effect does fast repetitive exercise have compared to slower muscle-building exercise?

As a drummer who likes to play high-energy music (fast, aggressive metal) it's safe to say I burn a fair amount of calories when doing so. But I've been drumming for over a decade and despite the ...
3
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2answers
141 views

Why we have to damage our muscles to build them?

I know that new muscle cells are made when actin fibers are disrupted. My hypothesis is that muscle mass is limited, from birth, and that nutrients (protein) are only directed to grow muscle when ...
3
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2answers
492 views

How do muscles help erect the spine?

Muscles of the spine help to support it against gravity. For example, the multifidi interweave throughout the vertebrae and, as I understand, sort of reinforce the spine. So let's suppose muscles help ...
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1answer
3k views

What will happen if the biceps stop contracting and instead triceps contract? [closed]

For example if i bend my arm the biceps contract and triceps relax but if I bend my arm and the triceps contract instead of biceps what effect would it have?
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0answers
47 views

What Effect Does Skin Redness Have On Underlying Tissue?

When someone applies a rubefacient ( something that increases blood flow to the skin, turning it red), what effect does this have on the underlying tissue? Is blood supply increased radially from ...
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3answers
4k views

Where does extra blood come from to fill your muscles during exercise?

Let's say I go to the gym and lift some weights an hour. During this time my arms will grow due to the "pump" -- the extra blood rushing in to feed the muscles. For example, I've measured about 2-3 ...
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0answers
28 views

Model for calculating muscular activity from external measures

A physiologist wants to measure the intensity of the activity of a muscle or muscle group over a certain period of time. But the physiologist cannot measure what happens inside the the muscle itself (...
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2answers
141 views

Are gizzard muscles voluntary or involuntary?

I started raising chickens this year. They have amazing appetites, and I often wonder what eating is like for them. They have no teeth, so they don't chew their food as they eat it. They do seem to ...
3
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1answer
80 views

Does tremor frequency generally increase as Parkinson's disease progresses?

I've been trying to research this question, but most if not all the on-line journals require costly subscription, and the studies that are posted look at tremor frequency with regards to other factors....
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0answers
52 views

Book recommendation on the human muscle system

I would like to learn more about the exact mechanism behind our movements, especially about what happens during intense training when anaerobic state arises.
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2answers
27k views

What causes muscles to generate heat on contraction?

I'm curious what the exact cause is of dramatic heat generation that comes along with muscle activity. Can anybody explain this in understandable language?
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2answers
629 views

Why a continuous supply of energy is needed to support a weight?

What motivates this question is the apparent discrepancy between the concept of Work in physics and in physiology. Work in physics is defined as the dot product of the force applied to move a certain ...
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1answer
213 views

Is there a way to examine amount of red/white muscle fibers without biopsy?

I want to conduct some research on red and white muscle fibers, why do some people tire during certain movements while others do not. Obviously I can't get a biopsy on the subjects so I wanted to hear ...
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1answer
216 views

How can octopus walk if muscles can only contract?

From this video it is evident, that octopus can make tentacles push: https://youtu.be/zaE-LwDowcU How is it possible, if it is said, that muscles can only contract? What types of muscles can ...
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1answer
313 views

How much mechanical stress can a skeletal muscle bear?

In the movie- Saw, for the last trap Bobby was told to insert metallic hooks into his pectoralis major muscle. In his fake story Bobby has raised himself successfully, but when he was "really" trapped,...
3
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1answer
349 views

Do muscles still hold glycogen reserves if there is no carbohydrate input

Afaik skeletal muscles take glucose from the blood to store it localy as glycogen, to be used in the case of intensive exercise. Does this still happen if the calorie input is exclusively made up ...
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2answers
478 views

Why is living muscle tissue seemingly able to restore its shape under force, while dead tissue is not?

When I press my finger, even with relatively little force, into beef or chicken (say, at a grocery store), the indentation remains. When I poke a cow with my finger, the indentation does not remain. ...
4
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1answer
344 views

Why do athletes see a dip in performance in their thirties?

I have noticed a lot of athletes hit their prime when they are in their 20s and that by the time they reach their 30s they are past it and start to decline. Great athletes tend to prolong their ...
3
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1answer
25k views

How is ATP involved in muscle contraction?

The sliding filament mechanism as explained by my text does not elaborate on how ATP is involved in the cross bridge binding and contraction process. How does muscle contraction utilize ATP? In my ...
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1answer
981 views

What causes muscle spasms?

What causes muscle spasms with muscles that are not in the heart ? Could it be some sort of stimulus overload that causes a massive contraction?
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2answers
1k views

Before I move my arm the brain sends signals - what causes the brain to send signals? [closed]

Please tell me what causes the brain to send signals, how does the brain send signals? can you tell me what happens between the point when you make an intention to pick up a glass of water, and before ...
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1answer
5k views

Our muscles give us the ability to move our arms but…? [closed]

I have a strange question, but let me tell you something first. If you think of this carefully, then you realize something, please try this right now: Contract your muscles only so that your arms ...
0
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1answer
426 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
3
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1answer
199 views

Involuntary twitches and apnoea during early phases of sleep

I assume most people either experienced or have seen people with the following phenomenon: in the early phases of sleep sometimes involuntary twitches occur that usually accompany the pause of ...
1
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1answer
904 views

Why use creatine phosphate?

We use creatine phosphate as an energy storage to resupply ADP with a phosphate group as our muscle cells only contain about 2-5 mM ATP. But why doesn't the muscle cells just keep 20-30 mM ATP instead ...
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3answers
14k views

Does taking a shower have the same effect on muscles as warming up?

When playing sports, coaches and trainers are always very clear that it is necessary to warm up and stretch. But sometimes athletes sometimes want to get an extra stretch in and don't want to go ...
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0answers
154 views

How do BCAA's promote faster muscle recovery?

I am aware that ingesting Branched chain amino acids (BCAA's) prior, during, and after workouts has an effect on muscle recovery due to their difficulty of metabolism. However, how much more ...
4
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1answer
139 views

Hand-eye coordination in 3D space

A simple daily event has amazed me and triggered this question. I have read and heard about hand-eye coordination. It quite straightforward when you e.g. want to open a door or play Xbox. In this case ...
7
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2answers
23k views

What physiological processes within a muscle cause the latent period in a muscle fiber?

This is a lab question I cant find the answer in the lab manual or in the text book. What physiological processes in a muscle cause the latent period in a muscle fiber? Please help. Edit: The latent ...
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2answers
10k views

Why does yawning impair hearing?

When I yawn I can't hear anything happening around me. I also feel some kind of muscles inside my head contract and hear a faint hum, but it is not loud enough to explain not hearing other sounds. I ...
2
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1answer
2k views

Is the Klein's bottle a good analogy to the relation between T-tubule and sarcolemma? [closed]

I am not quite seeing how the T-tubule and sarcolemma is connected. It says that the T-tubule is an "invagination" of the sarcolemma, which is sarcolemma folded from the inside to form a T-tubule Can ...
2
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1answer
4k views

When contracting a muscle will the muscle spindle stretch or contract?

When you contract your muscle, will your muscle spindle stretch or contract? And why? I was always under the impression that it was contracting your muscle spindle, but now I am not sure.
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1answer
584 views

if the load is removed from an eccentrically contracting muscle, will it start contracting concentrically?

Geometrically speaking, a muscle contraction should exert a force between the two attachment sites. However, the actual effect of the force on the overall geometry of the body near the point of ...