Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [muscles]

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

2
votes
1answer
851 views

How does motor nerve innervation determine type of muscle fibre?

Muscle fibres are of two types - type I and type II. They differ from each other in various properties. Even the underlying biochemical processes are different to suit their function (slow vs fast) ...
2
votes
1answer
6k views

Mechanism of Myosin Head Bending in Cross Bridge Cycle Power Stroke Phase

What is the mechanism of bending of myosin head during the power stroke of the cross-bridge cycle of the muscle contraction? Does this have anything to do with the protein's 3-D structure i.e. folding ...
1
vote
2answers
496 views

How do legs of tiny insects/spiders like mosquito/Opiliones work?

I think I understand how legs of humans work. We have bones to which muscles are attached. Muscles can only contract / relax. By the combination of many different muscles we can make complex movements:...
1
vote
1answer
61 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 ...
2
votes
0answers
57 views

Myoblasts Formation

Myoblasts arise from mesenchymal stem cells (MSCs), and are precursors to myocytes. In muscles, in the basement membrane, there are also present satellite cells which can divide to generate muscle ...
3
votes
0answers
52 views

How does gold chloride stain neuromuscular junctions?

Gold chloride is used in muscle biopsies to stain the NMJ. What is the substrate that it binds to?
1
vote
2answers
19k views

What is the difference between endomysium and sarcolemma [closed]

They both are lining of muscles so how can we differentiate these two? Please answer in simple terms.
1
vote
1answer
106 views

What is the state of actin-myosin in my biceps after I have flexed my arm?

When I'm starting to flex my arm, the myosin and actin slide over each other in a ratchet like mechanism. When I've totally flexed my arm, are the actinomyosin left in this contracted state? Since ...
3
votes
1answer
260 views

How do sarcomeres coordinate contraction?

As can be seen from the figure if myosins from both sides apply equal force then how does muscle contract? And also how do actins resist tearing? Is there any kind of coordination between different ...
4
votes
1answer
1k views

Are glands in human made up of muscles?

I came across this idea while reading an excerpt of my textbook $-$ Muscles move eye lid , tongue, beat the heart, popel food through gut, discharge wastes, squeeze out secretion from the glands ...
1
vote
1answer
52 views

Which of the response is faster? voice or hand action?

After taking certain stimuli and making the the decision to do certain action, which one response (output) (out of 2 possible output-ways, voice and hand-movement) would act faster? For example lets ...
1
vote
0answers
114 views

Are myosatellite cells myoblasts or do they differentiate into myoblasts?

Can satellite cells immediately fuse to a myotube/myofiber (meaning it is a myoblast already) or do they differentiate into a myoblast first and then fuse to myotubes/myofibers?
2
votes
1answer
604 views

When a muscle contracts, but not all the muscle fibers are activated, what happens to the remaining muscle fibers?

I understand how motor neurons work, but I would like clarification on what exactly is going on when a muscle contracts. For the sake of simplicity, let's just use the bicep as an example. If I do a ...
1
vote
0answers
23 views

Long-Term EMG studies

I am having trouble differentiating onset/offset of muscle activation. Is there anyone in the field has a specific way to set the threshold for both time and magnitude?
2
votes
0answers
100 views

In a sarcomere, during contraction, is chemical energy turned into elastic energy and then mechanical energy?

I'm familiar with the cross bridge cycle and how the sarcomere contracts, but I have two related questions. I’ve read that when the myosin head cocks, it’s similar to a spring-loaded mousetrap. But is ...
2
votes
3answers
4k views

What is the actual storage form of energy in muscles? ATP or Glycogen?

I was asked this question in my latest exam. I think the answer is Glycogen because ATP doesn't store energy for a long time so it isn't the ACTUAL storage of energy. Some classmates argue that in ...
0
votes
1answer
643 views

Storage of energy in muscles vs fat depos [closed]

How does the body control, where consumed energy (fat, glucose) is stored? And what is its strategy? More specific: 1) How does the body control storing glucose in muscles and not as (subcutan) fat? (...
0
votes
1answer
43 views

Physical activity in fasted state: Glucose for brain vs muscles [closed]

Let's consider this scenario: You do sports in the morning in a fasted state (i.e. without consuming any calories after waking). Your brain of course needs glucose and your liver probably still has ...
0
votes
1answer
61 views

What are the binding sites (or receptors) of cortisol?

I am in the process of a OCR GCSE Case Study, and my question is "Do the benefits of anabolic steroids outweigh the risks, which has an obvious conclusion. I need to know the scientific name, or a ...
4
votes
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 ...
0
votes
0answers
5k 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 ...
5
votes
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 ...
4
votes
1answer
6k 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 ...
2
votes
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.
2
votes
0answers
90 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? ...
1
vote
2answers
9k 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 ...
3
votes
0answers
143 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 ...
7
votes
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 ...
0
votes
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 ...
8
votes
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 ...
1
vote
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) ...
3
votes
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 ...
2
votes
0answers
68 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 ...
3
votes
0answers
648 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 ...
9
votes
1answer
541 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 ...
2
votes
1answer
10k 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 ...
1
vote
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
votes
2answers
138 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
votes
2answers
457 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 ...
-1
votes
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?
2
votes
2answers
138 views

By What Mechanism Does Heat Cause Muscle Relaxation?

Heat is commonly used "loosen" muscles, but what exactly is happening to relax the muscle? It wouldn't make sense that increased blood flow alone would relax muscle.
1
vote
0answers
43 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 ...
0
votes
0answers
27 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 (...
2
votes
2answers
125 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 ...
5
votes
1answer
2k views

What neuro-motor diseases cause the lower esophageal sphincter (LES) to malfunction?

Please note: This question is neither homework nor seeking medical advice. I'm simply asking for a factual, objective, biological explanation of the various neuro-motor diseases/illnesses that can act ...
5
votes
0answers
78 views

How is atrophied muscle different than normal muscle in a chemical or biological way?

I am a writer with a question for a story I'm working on. In it, the character suffers from muscle atrophy due to spinal damage. So that I can portray this accurately, what would cause this type of ...
4
votes
3answers
551 views

Why are our muscles limited to 7 Hertz?

I have heard from a (usually very knowledgeable) friend before, that a human can only tap his fingers 7 times per second. I generalized this to "our muscles are limited to 7 hertz" When my wife ...
3
votes
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....
3
votes
2answers
356 views

At what levels of muscle energy intake does catabolism start?

From my own reading, there are three ways used by the body to produce energy: Alactic anaerobic (direct degradation of ATP and creatine phosphate for regeneration of ATP) Lactic anaerobic (breakdown ...
0
votes
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.