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Tonic Vibration Reflex
Tonic vibration reflex is a sustained contraction of a muscle subjected to vibration. This reflex is caused by vibratory activation of muscle spindles — muscle receptors sensitive to stretch. Tonic vibration reflex is evoked by placing a vibrator — which in this case is typically an electrical motor with an eccentric load on its shaft — on a muscle's tendon. 30–100 Hz vibration activates receptors of the skin, tendons and, most importantly, muscle spindles. Muscle spindle discharges are sent to the spinal cord through afferent nerve fibers, where they activate polysynaptic reflex arcs, causing the muscle to contract. The effects of sustained vibratory stimulation on muscle contraction, posture and kinesthetic perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle
Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contraction, contract. Muscle tissue contains special Muscle contraction, contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins, present are two regulatory proteins, troponin and tropomyosin. Muscle is formed during embryonic development, in a process known as myogenesis. Skeletal muscle tissue is striated consisting of elongated, multinucleate muscle cells called muscle fibers, and is responsible for movements of the body. Other tissues in skeletal muscle include tendons and perimysium. Smooth and cardiac muscle contract involuntarily, without conscious intervention. These muscle types may be activated both through the interaction of the central nervous system as well as by innervation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Spindles
Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be processed by the brain as proprioception. The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. The muscle spindle has both sensory and motor components. * Sensory information conveyed by primary type Ia sensory fibers which spiral around muscle fibres within the spindle, and secondary type II sensory fibers * Activation of muscle fibres within the spindle by up to a dozen gamma motor neurons and to a lesser extent by one or two beta motor neurons ''.'' Structure Muscle spindles are found within the belly of a skeletal muscle. Muscle spindles are fusiform (spindle-shaped), a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrator (mechanical)
A vibrator is a mechanical device to generate vibrations. The vibration is often generated by an electric motor with an unbalanced mass on its driveshaft. There are many different types of vibrator. Typically, they are components of larger products such as smartphones, pagers, or video game controllers with a "rumble" feature. Vibrators as components When smartphones and pagers vibrate, the vibrating alert is produced by a small component that is built into the phone or pager. Many older, non-electronic buzzers and doorbells contain a component that vibrates for the purpose of producing a sound. Tattoo machines and some types of electric engraving tools contain a mechanism that vibrates a needle or cutting tool. Aircraft stick shakers use a vibrating mechanism attached to the pilots' control yokes to provide a tactile warning of an impending aerodynamic stall. Eccentric rotating mass (ERM) vibrators work by rotating a deliberately unbalanced weight, so the weight is eccentr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afferent Nerve Fiber
Afferent nerve fibers are axons (nerve fibers) of sensory neurons that carry sensory information from sensory receptors to the central nervous system. Many afferent projections ''arrive'' at a particular brain region. In the peripheral nervous system, afferent nerve fibers are part of the sensory nervous system and arise from outside of the central nervous system. Sensory and mixed nerves contain afferent fibers. Structure Afferent neurons are pseudounipolar neurons that have a single process leaving the cell body dividing into two branches: the long one towards the sensory organ, and the short one toward the central nervous system (e.g. spinal cord). These cells do have sensory afferent dendrites, similar to those typically inherent in neurons. They have a smooth and rounded cell body located in the ganglia of the peripheral nervous system. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal root known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflex
In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron, which evokes a target response. These neural signals do not always travel to the brain, so many reflexes are an automatic response to a stimulus that does not receive or need conscious thought. Many reflexes are fine-tuned to increase organism survival and self-defense. This is observed in reflexes such as the startle reflex, which provides an automatic response to an unexpected stimulus, and the feline righting reflex, which reorients a cat's body when falling to ensure safe landing. The simplest type of reflex, a short-latency reflex, has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Position
Human positions refer to the different physical configurations that the human body can take. There are several synonyms that refer to human positioning, often used interchangeably, but having specific nuances of meaning. *''Position'' is a general term for a configuration of the human body. *''Posture'' means an intentionally or habitually assumed position. *''Pose'' implies an artistic, aesthetic, athletic, or spiritual intention of the position. *''Attitude'' refers to postures assumed for purpose of imitation, intentional or not, as well as in some standard collocations in reference to some distinguished types of posture: " Freud never assumed a fencer's attitude, yet almost all took him for a swordsman." *''Bearing'' refers to the manner of the posture, as well as of gestures and other aspects of the conduct taking place. Basic positions While not moving, a human is usually in one of the following basic positions: All-fours This is the static form of crawling which is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system.Goldstein (2009) pp. 5–7 Vision involves light striking the retina of the eye; smell is mediated by odor molecules; and hearing involves pressure waves. Perception is not only the passive receipt of these signals, but it is also shaped by the recipient's learning, memory, expectation, and attention. Gregory, Richard. "Perception" in Gregory, Zangwill (1987) pp. 598–601. Sensory input is a process that transforms this low-level information to higher-level information (e.g., extracts shapes for object recognition). The following process connects a person's concepts and expectations (or knowledge) with restorative and selective mechanisms, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tendon Reflex
A tendon or sinew is a tough band of dense fibrous connective tissue that connects muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension. Tendons, like ligaments, are made of collagen. The difference is that ligaments connect bone to bone, while tendons connect muscle to bone. There are about 4,000 tendons in the adult human body. Structure A tendon is made of dense regular connective tissue, whose main cellular components are special fibroblasts called tendon cells (tenocytes). Tendon cells synthesize the tendon's extracellular matrix, which abounds with densely-packed collagen fibers. The collagen fibers run parallel to each other and are grouped into fascicles. Each fascicle is bound by an endotendineum, which is a delicate loose connective tissue containing thin collagen fibrils and elastic fibers. A set of fascicles is bound by an epitenon, which is a sheath of dense irregular connective tissu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H-reflex
The H-reflex (or Hoffmann's reflex) is a reflectory reaction of muscles after electrical stimulation of sensory fibers ( Ia afferents stemming from muscle spindles) in their innervating nerves (for example, those located behind the knee). The H-reflex test is performed using an electric stimulator, which gives usually a square-wave current of short duration and small amplitude (higher stimulations might involve alpha fibers, causing an F-wave, compromising the results), and an EMG set, to record the muscle response. That response is usually a clear wave, called H-wave, 28-35 ms after the stimulus, not to be confused with an F-wave. An M-wave, an early response, occurs 3-6 ms after the onset of stimulation. The H and F-waves are later responses. As the stimulus increases, the amplitude of the F-wave increases only slightly, and the H-wave decreases, and at supramaximal stimulus, the H-wave will disappear. The M-wave does the opposite of the H-wave. As the stimulus increases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nauka (publisher)
Nauka () is a Russian publisher of academic books and journals. Established in the USSR in 1923, it was called the USSR Academy of Sciences Publishing House until 1963. Until 1934 the publisher was based in Saint Petersburg, Leningrad, then moved to Moscow. Its logo depicts an open book with Sputnik 1 above it. Nauka was the largest scientific publishing house in the USSR, as well as in the world at one time (in 1982). It was also notable for being the publisher of the USSR Academy of Sciences and its branches. In 1972 Nauka published 135 scientific journals, including 31 physical and mathematical, 24 chemical, 29 biological and five popular science journals: ''Priroda'' (Nature), ''Zemlya i Vselennaya'' (Earth and the Universe), ''Khimia i zhizn'' (Chemistry and Life), ''Kvant (magazine), Kvant'' (Quantum), and ''Russkaya rech'' (Russian speech). The greater part of Nauka's production were monographs. It also published thematic collected works, reference books, textbooks and fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
