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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 increase physical endurance. Background Rather than moving continuously through the environment, many animals interrupt their locomotion with frequent brief ...


31

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 fingers are wrapped around a large cable, most adults will be able to let go with a current of less than 6 mA. At 22 mA, however, more than 99% of adults will ...


20

There are instances of insect muscle growth in response to increased use. The flight muscles of the tsetse fly (Glossina morsitans) have been observed to grow at a faster rate when subjected to enforced exercise (Anderson and Finlayson, 1976). Also larger mandibular adductor muscles (which power the feeding apparatus), and associated head capsule have been ...


12

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, the body can't handle the heat, thus severe burns occur after electric shock. But if the current is low enough not to burn "the conductor" other effects are ...


10

A recent paper called 'Genetic Influences in Sport and Physical Performance'[1] states: "Muscle fibre type determination is complex. Whilst initial composition is likely to be strongly influenced by genetic factors, training has significant effects on fibre shifts." They also go onto say that: "However, the role of genetic variation in determining ...


8

If you dissect striated muscle out of most-any organism, the actual contractile apparatus works over a wide range of temperatures. So that's at the single-muscle-fiber scale. The muscle itself continues to work at all (thawed) temperatures below body temperature -- the problem comes with its regulation. The shivering response -- a centrally controlled ...


8

The pressure that you apply when you push during a bowel movement derives from an increase in the pressure of the abdomino-pelvic cavity. You generate this pressure by closing the glottis (the opening to the lungs) and contracting the anteriolateral abdominal muscles (i.e., the external oblique, internal oblique, and transversus abdominus). This reduces ...


8

Good question that got me waist-deep in PubMed. It appears that the directionality of myosin motors is due to the angle at which the actin-binding catalytic domain is attached to the neck region. This review by Vale and Milligan, 2000, sums up the "unzippering" of the neck region that contributes the force for the movement (a video from the review adapted ...


8

The quick and simple answer: Cramps of a hypokalemic origin are much more common than those of a hyponatremic origin because the Na-K pump is more effective at moving potassium in comparison to sodium. At the onset of a muscle contraction, the presence of calcium triggers the opening of the Na-K channels in the membrane. Potassium is a calcium inhibitor, so ...


8

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 Difference in snappiness may result from difference in the ability to accelerate your movement. An increase in body size over one dimension (=body length) $x$ scales ...


7

It seems that you are asking about activity significantly above basal metabolic rate. If aerobic conditions are maintained (and with appropriate training), muscles can operate more or less continuously for very long durations, days to weeks. In non-humans: Godwits have been recorded flying over 7000 miles (>11000 km) without stopping for 9 days Arctic ...


7

I speak only for the U.S. regulations: the calorie labels on wrappers refer to the energy released when burned. Sometimes these are inaccurate. Many dieticians recommend calculating the calories based on weights of protein, carbohydrates and fats in the serving: 4 kcal in each gram of protein and carbohydrate and 9 kcal in each gram of fat in your food. ...


7

There is not a linear relationship between the size of a muscle and its power. The cat weighs significantly less, but the decline in muscle power is not identical. If he weighs 20x less than you, but his muscle generate 1/5 as much force, he will still be able to jump way higher than you.


7

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 an increase in muscle fiber diameter by an increase in fiber length. However, growth in cell numbers is limited to the prenatal and immediately postnatal ...


7

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. It's called muscular-hydrostat. Movement of the limb actually depends on which muscle is being contracted. If it's contracting the muscles longitudinally it ...


6

Well, if we look in very basic detail at how muscle contraction works within a myofibril of the sarcomere: N.b. this isn't on a loop and only plays through seven times The red lines represent actin filaments whilst the blue lines represent myosin filaments. During muscle contraction the filaments move over each other: As shown in the above ...


6

I would argue that the orbiculares do have antagonists. To some extent, levator palpebrae superiorus antagonizes orbicularis oculi, and zygomaticus major/minor as well as risorius antagonize orbicularis oris. I can think of three muscle that don't have obvious antagonists: Stapedius Tensor tympani Articularis genu 1 and 2 essentially perform the same ...


6

The dynamic-dominance hypothesis of handedness states that the essential factor that distinguishes dominant from nondominant arm performance is the facility governing the control of limb dynamics. Sainburg (1) writes that It should be noted that dominant arm advantages do not apply to all tasks, or all aspects of tasks. Healey et al. (1986) examined an ...


6

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 situations, if hypovolemia occurs, blood can also come from: splachnic vascular bed [5] But what attracts the blood into the muscle? The phenomenon is ...


6

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 this image (from the Wikipedia), which illustrates this process: There is also an animated picture available, which illustrates this process even better (from ...


6

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 feedback being needed. Background Muscles, skin and joints contain proprioceptic receptors. They sense position and movement of our limbs and trunk, they register ...


5

Older papers initially presumed that it was part of a mechanism called "catch" in invertebrates like molluscs which is a "sustained contraction." However, paramyosin was also found in insects. There is a very detailed review on invertebrate muscle from 2008 that you should read through (or, you know, search through) points out that recent evidence has ...


5

It is related to Eustachian tube. It links the back of throat and the middle ear and allows air pressure to equalize in the middle ear. When you yawn air pressure goes up in this and it bends the ear drum and causes impair hearing (notice, just impair and not stop). Yawning also helps to open Eustachian tube.


5

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 replace the health benefits of getting off the couch. With proper nutrition, muscle is built through exercise by adding sarcomeres [to muscle cells which ...


5

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 processes and there are tissues that grow because both processes happen. A Google search for muscular growth yields as first result Muscle hypertrophy. And this is ...


5

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 look at a hot object, it doesn't apear to be moving any more than a cold object, but on a scale much smaller than we can see, it's molecules are moving faster ...


5

Without answering the problem for you, because you have not shown work yet to try to figure out which is which, let me tell you that you have three options. Skeletal Muscle- striated, peripherally located nuclei, same thickness along length, non-branching Cardiac Muscle- striated, few centrally located nuclei, branches and anastamosis Smooth Muscle- ...


5

I was able to do some reading and research and I found some interesting information that was a). news to me. And b). the answer is yes... And no. A spasm can be the cause of a heart attack by causing the coronary artery to contract. When that artery contracts, it causes a dramatic decrease in blood flow to the heart. When the heart looses access to ...


5

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. As the vasodilation (increase in diameter of blood vessels) allows blood to move without resistance and which in turn nourish the tissues with sufficient oxygen ...



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