motor pathway

pathway /path·way/ (path´wa)

1. a course usually followed.

2. the nerve structures through which an impulse passes between groups of nerve cells or between the central nervous system and an organ or muscle.

3. metabolic p..

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accessory conducting pathway  myocardial fibers that propagate the atrial contraction impulse to the ventricles but are not a part of the normal atrioventricular conducting system.

afferent pathway  the nerve structures through which an impulse, especially a sensory impression, is conducted to the cerebral cortex.

alternative complement pathway  a pathway of complement activation initiated by a variety of factors other than those initiating the classical pathway, including IgA immune complexes, bacterial endotoxins, microbial polysaccharides, and cell walls. It does not include factors C1, C2, and C4 of the classical complement pathway but does include factors B and D and properdin.

amphibolic pathway  a group of metabolic reactions providing small metabolites for further metabolism to end products or for use as precursors in synthetic, anabolic reactions.

circus pathway  a ring or circuit traversed by an abnormal excitatory wavefront, as in reentry.

classical complement pathway  a pathway of complement activation, comprising nine components (C1 to C9), initiated by antigen-antibody complexes containing immunoglobulins IgG or IgM.

common pathway of coagulation  the steps in the mechanism of coagulation from the activation of factor X through the conversion of fibrinogen to fibrin.

Coagulation pathway overview.

efferent pathway  the nerve structures through which an impulse passes away from the brain, especially for the innervation of muscles, effector organs, or glands.

Embden-Meyerhof pathway  the series of enzymatic reactions in the anaerobic conversion of glucose to lactic acid, resulting in energy in the form of adenosine triphosphate (ATP).

Embden-Meyerhof pathway of glucose metabolism.

extrinsic pathway of coagulation  the mechanism that produces fibrin following tissue injury, beginning with formation of an activated complex between tissue factor and factor VII and leading to activation of factor X, inducing the reactions of the common pathway of coagulation.

final common pathway  a motor pathway consisting of the motor neurons by which nerve impulses from many central sources pass to a muscle or gland in the periphery.

intrinsic pathway of coagulation  a sequence of reactions leading to fibrin formation, beginning with the contact activation of factor XII, and resulting in the activation of factor X to initiate the common pathway of coagulation.

lipoxygenase pathway  a pathway for the formation of leukotrienes and hydroxyeicosatetraenoic acid from arachidonic acid.

Lipoxygenase pathway of leukotriene and hydroxyeicosatetraenoic acid synthesis. HPETE, hydroperoxyeicosatetraenoic acid; HETE, hydroxyeicosatetraenoic acid; LT, leukotriene.

metabolic pathway  a series of enzymatic reactions that converts one biological material to another.

motor pathway  an efferent pathway conducting impulses from the central nervous system to a muscle.

pentose phosphate pathway  a major branching of the Embden-Meyerhof pathway of carbohydrate metabolism, successively oxidizing hexoses to form pentose phosphates.

reentrant pathway  that over which the impulse is conducted in reentry.

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motor pathway

Etymology: L, movere, to move; AS, paeth

the route of motor nerve impulses, from the central neuron to a muscle or gland.

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motor,

n pertaining to a muscle, nerve, or center that produces or affects movement.

motor neuron,

n one of the various efferent nerve cells that transmit nerve impulses from the brain or from the spinal cord to muscular or glandular tissue.

motor neuron disease,

n a progressive disease that tends to affect middle-age men with degeneration of anterior horn cells, motor cranial nerve nuclei, and pyramidal tracts (e.g., amyotrophic lateral sclerosis).

motor output,

n the activity that results from the integrative phenomena associated with brain activity. It is expressed in function as muscle contraction of the smooth and striated muscle and as secretion of the exocrine and endocrine glands and, in effect, represents the total behavioral activity. Whereas sensory phenomena have many avenues that feed into the brain, motor activity is expressed in terms of the simple, direct state of muscle contraction and glandular secretion. Thus muscle activity is expressed in terms of locomotion, hand-learned skills, speaking, mastication, and all forms of activity that involve motion.

motor pathway,

n all reflex actions of muscle are achieved by the passage of nerve impulses through the final common pathway–the muscle fibers. The lower motor neuron (the motor route of the cranial nerve) is the final pathway for the structures that are innervated by the cranial nerves. Impulses traverse these nerves to their respective muscles from every level of the spinal cord, hindbrain, midbrain, and cerebral cortex. The cranial motor neurons collate these multiple stimuli and transmit sequences of stimuli to the motor end-plate, which in the normal muscle effects a smooth, continuous, controlled contraction.

motor skill,

n the ability to make the purposeful movements that are necessary to complete or master a prescribed task.

motor unit,

n the entity consisting of the lower motor neuron, motor end-plate, and muscle fibers supplied by the end-plate. The final motor activity resulting from a sequence of stimulations to the lower motor neuron is considered a function of the motor unit. The proportion of nerve fibers to the muscle fibers in motor units is designated as the innervation ratio. They may have ratios ranging from 1:4 to 1:150. The closer the ratio approximates unity, the greater the finesse of specificity of the muscular action. The eye muscles have the highest ratio of striated muscles, and the tongue, facial, masticatory, and pharyngeal muscles succeed in that order.

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motor pathway

Pathway from the cortex to the muscles that control the movements of the eyes enabling them to act as a unit.