Control of Movement Flashcards
flexion vs. extension
flexion:
A movement of a limb that tends to bend its joints; opposite of extension.
extension:
A movement of a limb that tends to straighten its joints; the opposite of flexion
isometric vs. isotonic
Isometric movement: Maintaining limb position while changing muscle tension
Isotonic movement: Changing limbe position without changing muscle tension
Extrafusal muscle fiber, intrafusal motor fiber
-extrafusal muscle fiber
Muscle fibers that are responsible for the force exerted by contraction of a skeletal muscle.
-intrafusal motor fiber
A muscle fiber that functions as a stretch receptor, arranged parallel to the extrafusal muscle fibers, thus detecting changes in muscle length.
alpha motor neuron
alpha motor neuron
A neuron whose axon forms synapses with extrafusal muscle fibers of a skeletal muscle; activation contracts the muscle fibers.
gamma motor neuron
gamma motor neuron
A neuron whose axons form synapses with intrafusal muscle fibers.
motor unit
A motor neuron and its associated muscle fibers.
myofibril
An element of muscle fibers that consists of overlapping strands of actin and myosin; responsible for muscular contraction
actin/myosin
One of the proteins (with actin) that provide the physical basis for muscular contraction.
stated muscle
Skeletal muscle; muscle that contains striations.
neuromuscular junction
The synapse between the terminal buttons of an axon and a muscle fiber.
motor endplate
The postsynaptic membrane of a neuromuscular junction
endplate potential
The postsynaptic potential that occurs in the motor endplate in response to release of acetylcholine by the terminal button. [therefore contraction]
smooth muscle
Nonstriated muscle innervated by the autonomic nervous system; found in the walls of blood vessels, in the reproductive tracts, in sphincters, within the eye, in the digestive system, and around hair follicles.
cardiac muscle
muscle for heart contractions, non skeletal
monosynaptic stretch reflex
A reflex in which a muscle contracts in response to its being quickly stretched; involves a sensory neuron and a motor neuron, with one synapse between them. (dropping weight muscle lengthens, increase firing MS affront, alpha motor, strength of contraction increased))
clasp knife reflex
A reflex that occurs when force is applied to flex or extend the limb of an animal showing decerebrate rigidity; resistance is replaced by sudden relaxation. This is due to inhibition from golgi tendon organs that inhibits muscle contraction
Posture adjustment
when we lean forward, muscle lengthens (MS fire, alpha motor stimulated) which leads to contraction which pushes toes down and therefore we lean back
somatotopic orginization
A topographically organized mapping of parts of the body that are represented in a particular region of the brain.
supplemental motor area
A region of association motor cortex of the dorsal and dorsomedial frontal lobe, rostral to primary motor cortex.
premotor area
gion of motor cortex of the lateral frontal lobe,
The “transcortical reflex”
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A long-latency EMG response to muscle stretch or cutaneous stimulation that depends on rapid transmission of the sensory volley and evoked motor volley and involves the cerebral cortex. Also known as a long loop reflex.
Sensorimotor reciprocity (a realistic model)
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attention is organized by intention (intention drives attention which controls action)
long fibres interconnect front/back of association cortex, short give immediate feedback
fastigial nucleus
A deep cerebellar nucleus; involved in the control of movement by the reticulospinal and vestibulospinal tracts.
interposed nucleus
A set of deep cerebellar nuclei; involved in the control of the rubrospinal system.
pontine nucleus
serves as an important source of input to the cerebellum.
dentate nucleus
A deep cerebellar nucleus; involved in the control of rapid, skilled movements by the corticospinal and rubrospinal systems.
mesencephalic locomotor region
A region of the reticular formation of the midbrain whose stimulation causes alternating movements of the limbs normally seen during locomotion.
