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51 votes
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Why do smaller mammals move intermittently?

Short answer Intermittent locomotion can increase the detection of prey by predators (e.g. rats), while it may lead to reduced attack rates in prey animals (e.g., rats and chipmunks). It may also ...
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37 votes
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Why does an electrical shock freeze up muscles?

Interesting question! An important factor here is the let-go phenomenon, which is defined as the current level in the arm that will cause the hand to involuntarily grip the current source. When the ...
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23 votes
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How did the largest/longest dinosaurs hold their head and necks up?

There are lots of papers on this. A good summary article is Why sauropods had long necks; and why giraffes have short necks, by Taylor​ and Wedel. They list a number of anatomical features that ...
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17 votes

Why do smaller mammals move intermittently?

In addition to @AliceD's excellent answer, I would like to add that a simple mechanistic relationship between body size and "snappiness" may explain the observed pattern. Basics of biophysics ...
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14 votes
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Do eye's muscle share the same nerve?

Each eye is controlled separately. Three cranial nerves emerge at the brain for each eye to control the so called extraocular muscles. That we usually move both eyes in one direction is due to that ...
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13 votes

Why does an electrical shock freeze up muscles?

When the body comes in contact with an electrical power supply, two things can happen. If the current flow is high enough, the body heats up just like a heating resistor, and opposed to the resistor, ...
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12 votes
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Bending your little finger without bending ring finger

This does not have to be the case always, For example if you are a pianist you need all your finger to work independently. OK, So coming to the main question. In simple words, They are all ...
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11 votes
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Where does extra blood come from to fill your muscles during exercise?

The blood comes from the body's reservoirs: spleen (mostly erythrocytes) [1] liver [2] veins (probably the most important blood resevoir as they contain 50-60 % of the volume) [3] In pathological ...
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10 votes
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Does muscle get bigger by increase in size of individual cells or increase in number?

The "back of your mind" is correct: "if the muscle gets bigger, it's simply because individual cells get bigger." Growth of muscle can occur in three ways: by an increase in muscle cell numbers by ...
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9 votes
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How can octopus walk if muscles can only contract?

Kier and Smith wrote a paper on how tongues tentacles and trunks worked. It explains in detail exactly how their legs (and our tongues) elongate, shorten and move about without any bones for support. ...
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9 votes
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Can acetylcholine leak away from the synapse and cause spasms?

The enzyme responsible for the breakdown of acetylcholine (Ach), i.e., acetylcholinesterase, rapidly degrades, and inactivates Ach in the synaptic cleft after release. This process is particularly ...
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8 votes
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Do both ends of a muscle contract?

The muscular fibers (or more exactly the actin and myosin filaments) are contracted towards each other. This makes them "move to the middle" and you build up a force on both sides of the muscle. See ...
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8 votes

Why does it hurt the next day after doing significant exercise?

It should be noted that in some people (somewhere between 1% and 3% of the population, depending on who's counting) there is another mechanism for delayed muscle pain. Myoadenylate Deaminase ...
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8 votes
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Biological Neural Network Training for Babies

Biological neurons function in a very different way, as compared to the simplistic artificial neural networks of machine learning. For example, see how real neurons work and how they connect with each ...
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7 votes
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What causes muscles to generate heat on contraction?

First, it might be helpful to talk briefly about what heat is. It is a form of energy - molecular energy. Basically, heat is the amount of jiggliness of the molecules of a substance or object. When we ...
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7 votes

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

How does extra blood come from to fill your muscles during exercise? Blood pumps (blood) and sucks (lymph). There are many pumps in our body thoracic pump smooth musculature respiratory pump which ...
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7 votes

Does muscle get bigger by increase in size of individual cells or increase in number?

A tissue can undergo two types of quantitative growth: hypertrophy - cells increase in size hyperplasia - cells increase in number There are tissues that grow as a result of one of the above ...
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  • 7,067
7 votes

What causes spontaneous muscle twitches?

Short answer Spontaneous muscle twitches are thought to be caused by spontaneous activation of motoneurons controlling the muscles. Background Spontaneous muscle activity (twitching) is referred to ...
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7 votes
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Are there genetic causes underlying the difference in circumference of the upper arm and foream?

The first answer explains that proximal limb segments do more "work" * using quotes to be careful w.r.t. technical definitions of work. Genetically, this is correct--it's the ancestral condition for ...
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  • 587
7 votes

Do eye's muscle share the same nerve?

There are basically four different types of eye movements: smooth pursuit (think about following a moving target with both your eyes, note how smooth the movement is) saccades (think about moving ...
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7 votes

Biological Neural Network Training for Babies

Some babies start walking by 12-15 months, so it's not exactly years before they can do it. They can also grasp things with their hands from birth. When first born they still don't have full ocular ...
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6 votes
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Can you build muscles from watching point of view videos of people weightlifting?

That is highly unlikely. The article to which you linked specifically states: While watching other people exercise may increase your heart rate and have other physiological effects, nothing can ...
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6 votes
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Hand-eye coordination in 3D space

Short answer Proprioceptic receptors provide a feedback mechanism from the body to the brain, telling the brain what our limbs are doing and where they are with respect to the body without visual ...
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6 votes

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

Hot shower will definitely affect your muscles health. Hot water shower results in Vasodilation,which will decrease the vascular resistance and allows blood to flow easily through the blood vessels. ...
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6 votes
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Why is there smooth muscle in our bronchioles?

There are at least two things to consider. First, ability to limit airflow is a defense mechanism for animal. Imagine getting into area of some sort of toxic evaporation, e.g. CO2 cloud near volcano ,...
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6 votes
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Are glands in human made up of muscles?

No they are not made of muscles. Glands are modified epithelial tissues. Glands are basically of two types Endocrine and Exocrine glands. Endocrine gland It is a gland that lacks a duct system. ...
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6 votes

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

Yes, there are genetic reasons for this. But your observation is either incorrect or abnormal. The shoulder (and hip) muscles do the heavier work, thus have larger (and bulkier) muscles. The more ...
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