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51

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 ...


35

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 ...


23

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 ...


23

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 allowed sauropods to support such long necks: Several anatomical features enabled this extreme elongation, including: absolutely large body size and quadrupedal ...


16

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 a difference in the ability to accelerate your movement. An increase in body size over one dimension (=body length) $x$ ...


14

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 our brain is trained that way. Nonetheless, we sometimes move each eye individually, for example when looking at an object that is very close to our face (...


13

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 interconnected. See the image [Source: Google Images] They share flexor tendons (The flexor tendons allow you to bend your fingers) , If you try to move one, other is ...


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 ...


11

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 ...


11

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 called ...


10

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 ...


10

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 ...


10

To shed some light on why this is happening in the first place, it may be helpful to understand the innervation of the muscles on these fingers. There are two nerves that innervate the little finger, both branches of the superficial ulnar nerve. One of them is exclusive to the little finger, but the other (the common palmar digital nerve) actually branches ...


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

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 ...


8

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 ...


8

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 ...


8

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 Deficiency (MADD) is a genetic condition whose primary symptom is pain and cramping with an onset about 36 hours after moderately intense exercise. The pain often ...


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

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 diagrams the "...


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

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.


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 terms ...


7

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 ...


7

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 ...


7

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 work together to provide the blood to the peripheral circulation. These pumps provide us Pulse, Vasomotor tone and Respiratory waves which when act together ...


7

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 ...


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