Skip to main content

Questions tagged [muscles]

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

Filter by
Sorted by
Tagged with
1 vote
2 answers
109 views

What is the linear force in a bicep compared to the force at the hand?

So I know that like most joints, the bicep applies a force near to the pivot (the elbow) and creates a rotational torque in the elbow, this moving the lever, your forearm and hand. Due to the biceps ...
0 votes
0 answers
23 views

Is there a mathematical expression linking effort required to lift a weight and the weight value?

I have no idea if this is the right forum but here we go I'm basically wondering if there is a math expression linking the amount of effort required to lift a weight at the gym, and the value of the ...
1 vote
1 answer
46 views

What goes on in the muscle during static exercise?

Starfish opens mollusc's shell by applying static force for several hours. Mollusc gets tired and cannot hold shell closed. Muscles spend some energy even when static exercise is done. But it is not ...
0 votes
1 answer
25 views

What is the difference between myoblasts, myotubes and myocytes

I am struggling to grasp the difference between myoblasts, myotubes and myocytes. If I am right, myoblasts are mononucleated and differentiate into myotubes which are muscle fibers. Are myocytes the ...
2 votes
0 answers
103 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 myosin filaments, the sarcomere is not functional. But how is the orientation of the myosin molecules determined? Why is ...
0 votes
0 answers
19 views

How do Action Potentials travel in Cardiac Muscle Cells?

From my reading, the action potential is generated by pacemaker cells within the SA node and the conduction system of the heart carries the action potential to the cardiac muscle cells. I was just ...
0 votes
0 answers
12 views

T-tubules in Muscle Cells

I understand that T-tubules are common to striated muscles such as skeletal and cardiac muscles (with smooth muscle cells having caveolae) but what precisely (if any) is the difference in the T-...
0 votes
0 answers
34 views

Muscle contraction and closing in of z line/disc

I have studied that during a contraction of myofibril, the globular heads of myosin attach to actin filaments and pull them towards the centre of the sarcomere pulling the z line/disc as well. What I ...
0 votes
0 answers
29 views

The amount of heat produced in muscles. A wrong answer

I'm trying to find how energy is released during muscle contraction. Seeing how no work is being produced, the issue is, after working out how much heat was theoretically produced by the heaviest ...
1 vote
0 answers
57 views

What happens to the gamma motor neuron during too much contraction of a muscle?

Suppose a muscle is contracting too much, so we need a reflex to stop it from contracting too much. Contraction of a muscle causes the muscle spindle to go slack, hence the Ia axons and II-axons do ...
3 votes
2 answers
82 views

Why is the ordinary cardiac muscle’s target value of the action potential 0mV?

Why do some excitable cells have a target of 0mV for the action potential, even with a slight overshoot? Excitable cells such as muscles and nerves have the ability to rapidly change their membrane ...
0 votes
0 answers
24 views

To where exactly does the sarcoplasmic reticulum release its calcium when stimulated?

I`m reading through medical physiology (2nd ed) by Boron & Boulpaep. On page 240 when describing the mechanism behind muscle activation, they write the following: After depolarization of the L-...
0 votes
2 answers
719 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 ...
0 votes
1 answer
39 views

Micro-intradermal spasms in the legs after exercise [closed]

Heyo ! When i'm doing physical effort that involves and then rest, I feel small and suddle of what feels like contraction all over my legs (but not feet); It stops by itself after a few minutes and ...
0 votes
0 answers
86 views

How are the muscles of some dead animals still able to function for an extended period of time without oxygen?

I found this video on youtube that features several butchered and sometimes cooked animals that are still able to move despite of this. Some of these animals have been dead for several hours already ...
0 votes
1 answer
884 views

Fibrosis vs stenosis vs sclerosis

I can't figure out the key distinguishing factors between these three and I keep seeing them being used almost interchangeably. For example aortic valve fibrosis and aortic valve stenosis. As much as ...
2 votes
0 answers
52 views

What keeps a muscle fiber in tension?

Someone in massage therapy told me that muscles require some chemical reaction to relax, and that magnesium helps with that. Looking into it, every source online I've found states that muscles relax ...
6 votes
2 answers
715 views

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 ...
0 votes
0 answers
61 views

Estimating Weight of Human Skeletal Muscle?

Is there a way to measure the weight of skeletal muscle? I understand body fat and lean body mass can be measured by: skin fold calipers, electrical impedance, table lookup based on formula of weight,...
5 votes
1 answer
130 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 ...
1 vote
1 answer
39 views

Would muscles still twitch if the applied potential is reversed?

In Galvani's experiment with frog legs, he applies an electric potential across the muscles of a frog which causes the leg muscles to contract. What would happen if the polarity was reversed (I do not ...
-1 votes
1 answer
339 views

What are the mechanical properties of human skeletal muscle?

TL;DR: I need more information on the mechanical properties of human skeletal muscle; if you have such information, please give it to me. I'm writing something on how much more effective (or otherwise)...
3 votes
1 answer
56 views

Simultaneous activation of myosin kinase (MLCK) and myosin phosphatase (MLCP)

Reading about smooth muscle cells, I stumbled upon this sentence in Guyton & Hall, Textbook of Medical Physiology (14th ed): When the myosin kinase and myosin phosphatase enzymes are both ...
0 votes
1 answer
256 views

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 ...
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 ...
5 votes
0 answers
122 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 ...
0 votes
0 answers
47 views

Are the muscles of all animals mechanically similar?

For instance, is the skeletal muscle of an elephant made of the same balance of fibers and cells as the skeletal muscle of a hippopotamus? I recognize that slow- and fast-twitch muscles are a thing, ...
1 vote
0 answers
218 views

Biological reason for "deadlift face"?

Always when I deadlift at the maximum load, my face looks more or less like this: or this: The same applies for when I do other heavy-weight exercises. But what biological mechanism causes that? ...
4 votes
1 answer
134 views

How long does it take for a new muscle fiber to be connected to motor neuron?

When new muscle fibers are formed through hypertrophy, how long does it take for motor neurons to connect to the new muscle cells in order to be able to control them? After taking a break from ...
2 votes
0 answers
21 views

What benefit do cardiomyocytes accrue by requiring calcium induced calcium release (relative to skeletal myocytes)?

According to 2 sources I've read, in contrast to skeletal myocytes, cardiac myocytes need calcium to diffuse in to result in contraction. One source says that they need large amounts of calcium to ...
1 vote
0 answers
21 views

Impact of increased sodium conductance at a neuromuscular junction

If trans-epithelial Na+ transport were to increase at the synapse(please consider both pre and post-synaptic membrane situations) in a neuromuscular junction, how would that manifest itself? My guess ...
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 ...
1 vote
0 answers
25 views

Is the nervous message sent by an eyelash being flexed sent all the way to the brain?

Since the reflex to close the eyelid once an eyelash is touched seems very fast, does the signal from the neuron detecting the touching travel all the way to the brain, get processed then back to the ...
0 votes
0 answers
25 views

Looking for literature on hand-head movement coordination (not hand-eye)

sports scientists and kinesiologists, I'm a linguist working on sign languages and I'm looking for papers that discuss motor coordination of hand and head movements and potential constraints on such ...
4 votes
1 answer
183 views

What happens to eyeball when you push your eye muscles harder? [closed]

I have myopia and I read that the rays of light intersect before the retina. When I can not see clearly I can push somehow my eye muscles and can see a bit clearly. The object gets clear but moves ...
2 votes
1 answer
103 views

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 ...
0 votes
0 answers
139 views

Humans best at long distance running: purely physiological or is it a function also of ability to pace?

I have read that although certainly other land animals are much faster over short distances, a human can run down any other animal over time, so that if a human is hunting like a gazelle, etc. ...
2 votes
2 answers
437 views

Are (muscle) satellite cells the same as muscle stem cells?

In terms of muscle: are the terms 'satellite cell' and 'muscle stem cell' interchangeable? That is, are there muscle stem cells that are not satellite cells, or vice versa?
2 votes
0 answers
52 views

What is the relationship between muscle energy consumption, the period over which the contraction occurs and the mechanical work performed?

I'm asking this question with some basic knowledge of physics and general fitness. Suppose you are lifting a still object with mass $m$ from height $h_1$ to height $h_2$ with an arbitrary (straight or ...
1 vote
1 answer
410 views

What are the roles of ATP and ADP in muscle contraction?

I've always known that the hydrolysis of ATP generates ADP, P, and energy, so I'd assume that if energy is necessary in a given process, ATP hydrolysis should occur (or another exothermic process). ...
-1 votes
1 answer
839 views

Why rectus abdominis is not proximal muscle?

I am thinking this picture which shows proximal muscles. Why for instance pectoralis major, subclavius and rectus abdominalis are not included in proximal muscles?
0 votes
2 answers
140 views

Why doesn't muscle strength depend on its length?

In case of tug of war the more people participate the more strength they represent. And in case of muscles - the longer it is, the greater the number of myosin heads bind to actin when muscles ...
8 votes
2 answers
6k views

Why is there smooth muscle in our bronchioles?

Having muscle tissue in our bronchioles that can constrict seems like a poor choice for tissue. Why would our airway want to ever close up? Wouldn't it be more beneficial for our bronchioles to just ...
0 votes
0 answers
173 views

Why does bicep activate during dead hang?

Hanging from a bar causes my bicep to feel much harder than when simply holding my arm straight above my head relaxed, without a bar. This was slightly surprising to me: I used to assume that since ...
1 vote
1 answer
1k views

Do animal muscles atrophy slower than humans?

Suppose I consider the silver back gorilla as an example. I cannot imagine ever seeing one in the wild intentionally doing something akin to weightlifting like humans solely for the purpose of ...
2 votes
0 answers
16 views

Most optically transparent muscle phantom?

I am trying to use Schlieren imaging techniques to visualize how a sound wave propagates through muscle tissue. In the past, when needing to experiment with muscle we would use an agar based muscle ...
-1 votes
1 answer
65 views

Does alcohol really helps to get substances get faster into the bloodstream? [closed]

I saw the video where Arnold Schwarzenegger cooks some protein cocktail and adds Austrian Schnapps to the mix, saying that it's to make everything get faster to the blood. Is it true or some kind of a ...
2 votes
2 answers
739 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 ...
4 votes
1 answer
171 views

Do multiple axons innervate a single skeletal muscle fiber?

The typical text-book illustration of innervation of muscle fibers shows branches at a single position along the fiber. Does any given muscle fiber have more axons that innervate it though, given that ...
1 vote
0 answers
221 views

What mammals can rotate and move their ears the most?

I found out that rabbits can rotate their ears 270 degrees, and also move them up, down and independently. Are there any other mammals that can control their ears' position that well, or even better?

1
2 3 4 5 6