8 Control Of Movement Flashcards
Flexion
A movement of the limbs that tends to bend its joints; the oppocite of extension.
Skeletal muscle
One of the striated muscles attached to the bones.
Extension
Movement of a limb that tends to straighten its joints; opposite of flexion.
Extrafusal muscle fiber
One of the muscle fibers that are responsible for the force exerted by contracting of a skeletal muscle.
Alpha motor neuron
Neuron whose axons forms synapses with extrafusal muscles fibers of a skeletal muscle; activation contract the muscle fibers.
Intrafusal muscle fiber
A muscle fiber that functions as a stretch receptor, arrange parallel to the extrafusal muscle fibers, just detecting changes in muscle length.
Gamma motor neuron
Neuron whose axons form synapses with intrafusal muscle fibers.
Motor unit
Motor neuron and its associated muscle fibers.
Myofibril
Element of muscle fibers that consist of overlapping strands of actin and myosin; responsible for muscular contractions.
Actin
One of the proteins (with myosin) that provide the physical basis for muscular contraction.
Myosin
One of the proteins (with actin) that provides the physical basis for muscular contraction.
Striated muscle
Skeletal muscle; muscle that contains striations.
Neuromuscular junction
Synapse between the terminal buttons of an axon and a muscle fiber.
Motor endplate
Postsynaptic membrane of the neuromuscular junction.
Endplate potential
Postsynaptic potential that occurs in the motor endplate in response to release of acetylcholine by the terminal button.
Golgi tendon organ
Receptor organ at the junction of the tendon and muscle that is sensitive to stretch.
Monosynaptic stretch reflex
Reflects 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.
Decerebrate
Describes an animal whose brainstem has been transected.
Decerebrate rigidity
Simultaneous contraction of agonistic and antagonistic muscles; caused by the cerebration or damage to the particular formation.
Clasp-knife reflex
Reflects that occurs when force is applied to flex or extend the limb of an animal showing decerebrate rigidity; resistance is replaced by sudden relaxation.
Somatotopic organization
Topographically organized mapping of parts of the body that are represented in a particular region of the brain.
Supplementary motor area (SMA)
Region of motor association cortex of the dorsal and dorsomedial frontal lobe, rostral to the primary motor cortex.
Premotor cortex
Region of motor association cortex of the lateral frontal lobe, rostral to the primary motor cortex.
Lateral group
Corticospinal tract
Corticobulbar tract
Rubrospinal tract
Ventromedial group
Vestibulospinal tract
Tectospinal tract
Reticulospinal tract
Ventral corticospinal tract
Corticospinal tract
System of axons that originates in the motor cortex and terminates in the ventral gray matter of the spinal cord.
Pyramidal tract
Portion of the corticospinal tract on the ventral border of the medulla.
Lateral corticospinal tract
System of axons that originates in the motor cortex and terminates in the contralateral ventral gray matter of the spinal cord; controls movements of the distal limbs.
Ventral corticospinal tract
System of axons that originates in the motor cortex and terminates in the ipsilateral eventual gray matter of the spinal cord; controls movements of the upper legs and trunk.
Corticobulbar tract
Bundle of axons from the motor cortex to the fifth, seventh, ninth, 10th, 11th, and 12 cranial nerves; controls movements of the face, neck, tongue, and parts of the extraocular eye muscles.
Rubrospinal tract
System of axons that travels from the red nucleus to the spinal cord; controls independent limb movements.
Corticorubral tract
System of axons that travels from the motor cortex to the red nucleus.
Vestibulospinal tract
Bundle of axons that travels from the vestibular nuclei to the gray matter of the spinal cord; controls postural movements in response to information from the vestibular system.
Tectospinal tract
Bundle of axons that travels from the tectum to the spinal cord, coordinates head and trunk movements with eye movements.
Reticulospinal tract
Bundle of axons a travel from the reticular formation to the gray matter of the spinal cord; controls the muscles responsible for postural movements.
Mirror neurons
Neurons 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.
Parietal reach region
Region in the medial posterior parietal cortex that plays a critical role in control of pointing or reaching with the hands.
Apraxia
Difficulty in carrying out purposeful movements, in the absence of paralysis or muscular weakness.
Constructional apraxia
Difficulty in drawing pictures or diagrams or in making geometrical constructions of elements such as building blocks or stick; caused by damage to the right parietal lobe.
Caudate nucleus
Telencephalic nucleus, one of the input nuclei of the basal ganglia; involved with control of voluntary movement.
Putamen
Telencephalic nucleus; one of the input nuclei of the basal ganglia; involved with control of voluntary movement.
Globus pallidus
Telencephalic nucleus; primary output nucleus of the basal ganglia; involved with control of voluntary movement.
Ventral anterior nucleus (of thalamus)
Thalamic nucleus that receives projections from the basal ganglia and sends projections to the motor cortex.
Ventrolateral nucleus (of thalamus)
Thalamic nucleus that receives projections from the basal ganglia and send projections to the motor cortex.
Subthalamic nucleus
Nucleus located ventral to the thalamus, an important part of the subcortical motor system that includes the basal ganglia, a target of deep-brain stimulation for treatment of Parkinson’s disease.
Direct pathway (in basal ganglia)
Pathway that includes the caudate nucleus and putamen, the internal division of the globus pallidus, and ventral anterior/ventrolateral thalamic nuclei; has an excitatory effect on movement.
Indirect pathway (in basal ganglia)
Pathway that includes the caudate nucleus and putamen, the external division of the globus pallidus, the subthalamic nucleus, the internal division of the globus pallidus, and the ventral interior/ventrolateral thalamic nuclei; has an inhibitory effect on movement.
Hyperdirect pathway
Excitatory pathway from that pre-SMA to the subthalamic nucleus that increases the activity of the GPi and appears to play a role in preventing or quickly stopping movements that are being initiated by the direct pathway.
Huntington’s disease
Fatal inherited disorder that causes degeneration of the caudate nucleus and putamen; characterized by uncontrollable jerking movements, riveting movements, and dementia.
Flocculonodular lobe
Region of the cerebellum; involved in control of postural reflexes.
Vermis
Portion of the cerebellum located at the midline; receive somatosensory information and helps to control the vestibulospinal and reticulospinal tracks through its connections with the fastigial nucleus.
Interposed nuclei
Set of deep cerebellar nuclei; involved in the control of the rubrospinal system.
Pontine nucleus
Large nucleus in the pons that serves as an important source of input to the cerebellum.
Dentate nucleus
Deep cerebellar nucleus; involved in the control of rapid, skilled movements by the cortical spinal 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.
