muscle contraction
Quick Summary
Muscle contraction is a complex physiological process initiated by a nerve impulse. This impulse, an action potential, travels along the muscle fiber's membrane to the myofilaments. Calcium ions are released, binding to troponin and removing the inhibition of actin-myosin interaction. Myosin then uses energy from ATP to slide along actin filaments, causing the muscle fiber to shorten and contract. This sliding filament mechanism is the fundamental basis of muscle contraction. The process is regulated by proteins like tropomyosin and troponin. For contraction to occur, the nerve signal is transmitted chemically at the neuromuscular junction via acetylcholine. Calcium ions play a crucial role, entering the cell and triggering further release from the sarcoplasmic reticulum, which ultimately allows actin and myosin to interact.12345
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muscleWhole muscleStriated 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…
Read MoreStriated 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…
Read More- muscleStructure and organization
…to that seen in skeletal muscle.
Read More…to that seen in skeletal muscle.
Read More - muscleInitiation of contraction
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…
Read MoreSmooth 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…
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- fatigue
…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.
Read More…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.
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human cardiovascular systemRegulation of heartbeat…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…
Read More…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…
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mechanoreceptionMuscle spindlesThe 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…
Read MoreThe 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…
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skeletonGeneral characteristics…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…
Read More…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…
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physiologyMetabolism…the energy for fermentation or muscle contraction depends on a series of reactions now known as glycolysis. In order to show that the conversion of glycogen to lactic acid could provide the necessary energy for muscular contraction, extremely delicate measurements of the heat produced by contracting muscles were required. As…
Read More…the energy for fermentation or muscle contraction depends on a series of reactions now known as glycolysis. In order to show that the conversion of glycogen to lactic acid could provide the necessary energy for muscular contraction, extremely delicate measurements of the heat produced by contracting muscles were required. As…
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muscle diseaseIndications of muscle disease…of intermittent spasms, or involuntary contractions, of muscles, particularly in the arms and legs and in the larynx, or voice box; it results from low levels of calcium in the blood and from alkalosis, an increased alkalinity of the blood and tissues. Tetanus, also called lockjaw, is a state of…
Read More…of intermittent spasms, or involuntary contractions, of muscles, particularly in the arms and legs and in the larynx, or voice box; it results from low levels of calcium in the blood and from alkalosis, an increased alkalinity of the blood and tissues. Tetanus, also called lockjaw, is a state of…
Read More- muscle diseaseClassification of muscle weakness
Muscle contraction results from a chain of events that begins with a nerve impulse traveling in the upper motor neuron from the cerebral cortex in the brain to the spinal cord. The nerve impulse then travels in the lower motor neuron from the spinal cord…
Read MoreMuscle contraction results from a chain of events that begins with a nerve impulse traveling in the upper motor neuron from the cerebral cortex in the brain to the spinal cord. The nerve impulse then travels in the lower motor neuron from the spinal cord…
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actinWhen a signal for muscle contraction is sent along a nerve to a muscle cell, actin and myosin are activated. Myosin works as a motor, hydrolyzing adenosine triphosphate (ATP) to release energy in such a way that a myosin filament moves along an actin filament, causing the two filaments…
Read MoreWhen a signal for muscle contraction is sent along a nerve to a muscle cell, actin and myosin are activated. Myosin works as a motor, hydrolyzing adenosine triphosphate (ATP) to release energy in such a way that a myosin filament moves along an actin filament, causing the two filaments…
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cellActin filaments…create the force responsible for muscle contraction. When the signal to contract is sent along a nerve to the muscle, the actin and myosin are activated. Myosin works as a motor, hydrolyzing adenosine triphosphate (ATP) to release energy in such a way that a myosin filament moves along an actin…
Read More…create the force responsible for muscle contraction. When the signal to contract is sent along a nerve to the muscle, the actin and myosin are activated. Myosin works as a motor, hydrolyzing adenosine triphosphate (ATP) to release energy in such a way that a myosin filament moves along an actin…
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human nervous systemMovement…brought about by the harmonious contraction and relaxation of selected muscles. Contraction occurs when nerve impulses are transmitted across neuromuscular junctions to the membrane covering each muscle fiber. Most muscles are not continuously contracting but are kept in a state ready to contract. The slightest movement or even the intention…
Read More…brought about by the harmonious contraction and relaxation of selected muscles. Contraction occurs when nerve impulses are transmitted across neuromuscular junctions to the membrane covering each muscle fiber. Most muscles are not continuously contracting but are kept in a state ready to contract. The slightest movement or even the intention…
Read More- sarcoplasmic reticulum
…role in determining whether muscle contraction occurs.
Read More…role in determining whether muscle contraction occurs.
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