Movement (145-166) Flashcards
Final common pathway
Skeletal muscles can only be reach through the spinal or brainstem motoneuron.
Somatotopy
Topography in the somatosensory and motor system
Intrafusal fiber
A modified muscle fiber in the muscle spindle
Extrafusal fiber
Muscle fibers outside the muscle spindle
Annulospiral ending
The terminal of the Ia fiber on the intrafusal fiber
Miotatic reflex (stretch reflex)
A monosynaptic reflex starting from the muscle spindle and causing contraction of the muscle on stretching
Inverse miotatic reflex (tendon reflex)
A bisynaptic reflect starting from the tendon organ; it protects the muscle and tendon by relaxing the muscle when extreme tension develops.
Motor unit
A collection of muscle fibers innervated by the same motoneuron.
Motoneuron pool
A collection of motoneurons innervating muscle units in the same muscle.
Red muscle fiber
Muscle fiber characterized by good blood supply, many mitochondria, high myoglobin content and slow fatigue.
White muscle fiber
Muscle fiber characterized by few mitochondria, low myoglobin content, quick fatigue, but very fast contraction.
Renshaw neuron
Inhibitory neuron in the spinal cord, excited by a collateral of the alpha motoneuron and providing negative feedback to the motoneuron.
Decerebrate rigidity
Increase of the muscle tone caused by the transection of the brain stem above the Deiter´s nucleus.
Muscle tone
Continuous, slight contraction of the skeletal muscles important in the maintenance of the posture.
Purkinje neuron
GABAergic inhibitory neuron providing the main output of the cerebellum
Deep cerebellar nucleus
Most of the cerebellar Purkinje cells project through these nuclei to other parts of the brain.
Vestibulocerebellum (archicerebellum)
The most ancient part of the cerebellum. Its input comes from the vestibular organ, and its main function is to keep posture and balance.
Spinocerebellum (Paleocerebellum)
Consists of the vermis and the intermediate part of the hemispheres. It monitors the execution of motor commands issues by the cortex.
Cerebrocerebellum (neocerebellum)
The newest part of the cerebellum, consisting of the lateral part of the hemispheres. It plays a role in the learning, starting and stoping movements.
Basal ganglia
The collective name for subcortical nuclei involved in motor control.
Parkinson´s disorder
A movement disorder caused by the insufficient production and release of dopamine in the neostriatum. It causes tremor and decreased initiation of movements.
Huntington´s chorea
A genetic neurological disorder leading to loss of GABAergic and cholinergic cells in the neostratium, leading to jerky, random, uncontrollable movements.
