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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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14 votes
3 answers
5k 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 ...
CaptainCodeman's user avatar
3 votes
1 answer
27k 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 ...
Fraïssé's user avatar
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7 votes
3 answers
6k views

Do both ends of a muscle contract?

I was under the impression that both ends of a muscle contract. For instance, the fibers of the biceps run parallel to the humerus so I thought they pulled toward the middle. But now I'm confused ...
Stan Shunpike's user avatar
1 vote
0 answers
31 views

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. ...
wav scientist's user avatar
1 vote
1 answer
2k views

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 ...
Franck Dernoncourt's user avatar
64 votes
2 answers
8k views

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 ...
user1995's user avatar
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62 votes
3 answers
11k views

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 ...
Fraïssé's user avatar
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30 votes
2 answers
23k views

Why does an electrical shock freeze up muscles?

Why is it when someone comes into contact with an electrical supply that their body freezes up and is unable to move away from the electrical source? Can someone explain this through a physiological ...
Fraïssé's user avatar
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25 votes
1 answer
7k views

Do insects' muscles become stronger with exercise?

I am curious to know if insect muscles become stronger with exercise, because I have seen many insects get tired out, but I have never seen one get stronger. They always seem to become permanently ...
J. Musser's user avatar
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12 votes
6 answers
51k views

What is the cause of muscle cramps?

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 ...
Kenshin's user avatar
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9 votes
1 answer
860 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 ...
rafraf's user avatar
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9 votes
4 answers
27k views

Why is it that cats can jump so high for their size, compared with humans?

My cat is about 1' high at the shoulder, and I am a little over 6', but my cat can easily jump onto something as high as I am. That is 6x it's height. If a cat can do this, then Why can't I jump up ...
J. Musser's user avatar
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5 votes
1 answer
459 views

Mechanism of Muscle Growth

According to this video (sorry for the poor reference but it represents my level of understanding in physiology), muscle grow as a consequence of repairing micro-lesions. How are these micro-lesions ...
Sulawesi's user avatar
  • 273
5 votes
1 answer
134 views

What is the actual molecular mechanism for muscle relaxation?

A number of my students asked what happens to the sliding filaments when muscles relax. For example, in an individual sarcomere, do all myosin heads release all at once or one/few at a time? More ...
theforestecologist's user avatar
4 votes
1 answer
9k 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 ...
Tyto alba's user avatar
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3 votes
0 answers
197 views

What controls the feeling of discomfort/comfort before and after sleep?

I'm interested in which biological systems or hormones are involved in the following phenomenon: Before sleep it may be difficult to find a comfortable position, and muscular aches and pains are more ...
Alex Stone's user avatar
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3 votes
2 answers
3k views

Correlation between muscle size and absolute strength

Is there a linear connection between muscle size and the power it can produce? If not, why? And what is the true correlation if any, can it be described with an appropriate function? What other ...
zeller's user avatar
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3 votes
2 answers
786 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 ...
Omar Nagib's user avatar
3 votes
1 answer
253 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 ...
Nandor Poka's user avatar
  • 3,118
2 votes
2 answers
755 views

Why is muscle force more dependent on cross-sectional area than on fiber length?

I was looking up why smaller animals are proportionally stronger than larger animals. The answer that comes back everytime is that muscle force depends on the number of muscle fibers, which is ...
Gabel Luc's user avatar
2 votes
1 answer
156 views

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, ...
Stanislav Bashkyrtsev's user avatar
1 vote
1 answer
99 views

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 ...
Franck Dernoncourt's user avatar
0 votes
0 answers
448 views

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 ...
Franck Dernoncourt's user avatar