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| Striated muscles attached to bones; implicated in behavior and control of movement |
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| Movement of a limb that tends to bend its joints (i.e., drawn in) |
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| Movement of a limb that tends to straighten its joints (i.e., movement away from the body) |
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| Responsible for force exerted by contraction of a skeletal muscle; served by alpha motor neurons |
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| (aka "muscle spindles") Functions as a stretch receptor, arranged parallel to extrafusal fibers, thus detecting changes in muscle length; served by gamma motor neurons |
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| Neuron whose axon forms synapses with extrafusal fibers; activation contracts the muscle fibers |
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| Neuron whose axons form synapses with intrafusal fibers |
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| Lower ratio of extrafusal fibers to neurons result in greater contractile power (i.e., hands) |
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Definition
| Consists of an alpha motor neuron, its axon, and associated extrafusal muscle fibers |
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| Element of muscle fibers that consists of overlapping strands of actin and myosin; responsible for muscular contractions |
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| The proteins that provide the physical basis for muscular contraction; myosin cross bridges "row" across actin, causing the filaments to move relative to each other |
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Definition
| Synapse between the terminal button of a motor neuron and a muscle fiber |
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| Postsynaptic membrane of a neuromuscular junction (i.e., the portion of the muscle fiber on which the motor neuron forms its synapse) |
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Definition
| Depolarization on endplate produced by release of ACh by the terminal button; potential is about 70mV, compared to 1mV for regular synapses (always causes AP in the muscle fiber) |
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| Action potential of muscle fiber |
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Definition
| ACh binds to receptor, causing receptor to open its channel; allows passage of Na+ ions into the fiber; causes depolarization, opening Na+ channels that cause AP to occur |
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Definition
| AP opens Ca+ channels, allowing Ca+ ions to enter cytoplasm, triggering the contraction; Ca+ causes myofibrils to extract energy from cytoplasmic ATP, causing myosin to "row" along actin filaments |
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| Strength of muscle contraction |
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Definition
| Depends on average rate of firing |
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Term
| Stretch receptors (of intrafusal fibers) |
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Definition
| Detects length of muscle (i.e., "where); stretch as muscle gets longer and shrink as muscle gets shorter |
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| Stretch receptors (of Golgi tendon organs) |
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Definition
| Located at junction of tendon and muscle; detects how hard a muscle is pulling on a tendon (i.e., "how heavy") and encodes this info in rate of firing |
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Term
| Muscle and tendon afferent axons |
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Definition
| MS1 - detects position; MS2 - detects rapid movement; GTO - detects stress on the muscle |
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Term
| Monosynaptic stretch reflex |
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Definition
| Reflex in which a muscle contracts in response to being quickly stretched; involves a sensory and motor neuron, with one synapse between them |
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| Monosynaptic reflex (Ranaldi def.) |
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Definition
| Afferent neuron connects fibers from muscle spindle to spinal cord; neuron enters spinal cord thru dorsal root, synapses on alpha motor neuron |
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Definition
| Involves more than just one synapse between two neurons; modulates activity from brain |
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| A topographically organized mapping of parts of the body that are represented in a particular region of the brain |
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| Supplementary motor area (SMA) |
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Definition
| A region of motor association cortex of the dorsal and dorsomedial frontal lob, rostral to the primary motor cortex |
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Definition
| A region of motor association cortex of the lateral frontal lobe, rostral to the primary motor cortex |
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Definition
| Involved in independent limb movement or muscle movements occurring independently of other muscle movements (e.g., fingers); consists of lateral corticospinal, corticobulbar, and rubrospinal tracts |
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Definition
| Involved in automatic and coordinated movements (e.g., posture and locomotion); consists of vestibulospinal, tectospinal, reticulospinal, and ventral corticospinal tracts |
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| Lateral corticospinal tract |
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Definition
| Controls distal parts of limbs (arms, hands, fingers, lower legs, feet, toes); synapse on motor neurons of spinal cord (at contralateral ventral gray matter) |
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| Ventral corticospinal tract |
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Definition
| Controls trunk and upper legs; synapse on motor neurons of spinal cord (at ipsilateral ventral gray matter) |
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Definition
| Controls face, tongue, and jaw; travels from motor cortex to cranial nerve nuclei |
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| Rubrospinal (or corticorubral) tract |
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Definition
| Controls lower legs, feet, and arms; travels from red nucleus to spinal cord |
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| Controls posture thru info from vestibular systems; travels from vestibular nuclei to spinal cord |
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| Coordinates eye movements w/ head/trunk; travels from superior colliculi to spinal cord |
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| Controls posture and locomotion; travels from reticular formation to spinal cord |
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| Located in the ventral premotor cortex and inferior parietal lobule that respond when the individual makes a particular movement or sees another individual making that movement |
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