muscle contraction

Striated muscle contracts to move limbs and maintain posture. Both ends of most striated muscles articulate the skeleton and thus are often called skeletal muscles. They are attached to the bones by tendons, which have some elasticity provided by the proteins collagen and elastin, the major…

…to that seen in skeletal muscle.

Smooth muscle cells contract in response to neuronal or hormonal stimulation, either of which results in an increase in intracellular calcium as calcium enters through membrane channels or is released from intracellular storage sites. The elevated level of calcium in the cell cytoplasm results…

…propose the sliding-filament theory of muscle contraction. An explanation for the conversion of chemical energy to mechanical energy on the molecular level, the theory states that two muscle proteins, actin and myosin, arranged in partially overlapping filaments, slide past each other through the activity of the energy-rich compound adenosine triphosphate…

The contraction of skeletal muscles is an energy-requiring process. In order to perform the mechanical work of contraction, actin and myosin utilize the chemical energy of the molecule adenosine triphosphate (ATP). ATP is synthesized in muscle cells from the storage polysaccharide glycogen, a…

…level), it is simply called muscle contraction. Muscle contraction occurring as an integrated part of more complex personalistic behaviour may be called reaching; this action is an integral part of grasping a pencil, which is part of the more personalistic act of writing to one’s friends.

…to stimulate the muscle to contract rhythmically. That these rhythmic contractions originate in the cardiac muscle can be substantiated by observing cardiac development in the embryo (see above); cardiac pulsations begin before adequate development of nerve fibres. In addition, it can be demonstrated in the laboratory that even fragments of…

The length of the muscle spindle as a whole varies with the contraction phase and the length of the muscle to which it belongs. The length of the sensory midsection, however, may change more or less independently because its motor nerve endings function apart from the innervation of the…

…chain lie the great axial muscles of the body; the fibres of this complex group of muscles are more or less parallel to the long axes of the vertebrae. One pair of vertebrae and its associated musculature form the fundamental unit of propulsion. The muscles on the two sides of…