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The somatic nervous system controls all voluntary muscular systems within the body, and the process of voluntary reflex arcs. [ 10 ] The basic route of nerve signals within the efferent somatic nervous system involves a sequence that begins in the upper cell bodies of motor neurons ( upper motor neurons ) within the precentral gyrus (which ...
The vocal cords are composed of twin infoldings of 3 distinct tissues: an outer layer of flat cells that do not produce keratin (squamous epithelium). Below this is the superficial layer of the lamina propria, a gel-like layer, which allows the vocal fold to vibrate and produce sound. The vocalis and thyroarytenoid muscles make up the deepest ...
The sound of each individual's voice is thought to be entirely unique [13] not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body, especially the vocal tract, and the manner in which the speech sounds are habitually formed and articulated. (It is this ...
This equivalency in motor action means that there is no one-to-one correspondence between the desired movements and the coordination of the motor system needed to execute those movements. Any desired movement or action does not have a particular coordination of neurons, muscles, and kinematics that make it possible.
According to the National Institute of Health, "voluntary control of the tensor tympani muscle is an extremely rare event", [5] where "rare" seems to refer more to the scarcity of test subjects and/or studies than the percentage of the general population who have voluntary control. The rumbling sound can also be heard when the neck or jaw ...
[3]: 4 There are five major parts of the vocal tract that move: the lips, the flexible front of the tongue, the body of the tongue, the root of the tongue together with the epiglottis, and the glottis. They are discrete in that they can act independently of each other, and two or more may work together in what is called coarticulation.
Skeletal muscle, is a type of striated muscle, composed of muscle cells, called muscle fibers, which are in turn composed of myofibrils. Myofibrils are composed of sarcomeres, the basic building blocks of striated muscle tissue. Upon stimulation by an action potential, skeletal muscles perform a coordinated contraction by shortening each sarcomere.
The pyramidal motor system, also called the pyramidal tract or the corticospinal tract, start in the motor center of the cerebral cortex. [4] There are upper and lower motor neurons in the corticospinal tract. The motor impulses originate in the giant pyramidal cells or Betz cells of the motor area; i.e., precentral gyrus of cerebral cortex ...