Postural control and locomotion Flashcards
Motor neurons innervating axial and proximal muscles are in the medial or lateral part of the anterior horn of the spine?
Medial
Motor neurons innervating distal muscles are in the lateral or medial part of the anterior horn of the spine?
Lateral
What is the function of the lateral corticospinal tract?
Voluntary control of the flexors of the hands and digits
What is the function of the rubrospinal tract?
Recall this is the ape one–flexion of the hands and the digits
What is the function of the ventromedial pathway?
Posture and locomotion via axial extensor muscle excitation
What is the origin, route, and termination of the lateral vestibulospinal tract?
Origin = vestibular nuclei
Route = all spinal cord
Terminates on extensor and flexor muscles of the limbs and girdle
What is the function of the lateral vestibulospinal tract?
provides way for vestibular input to affect posture
What is the origin, route, and termination of the medial vestibulospinal tract?
•origin – vestibular nuclei
•only descends as far as upper thoracic cord
Terminates in the muscles of the head and neck
What is the function of the medial vestibulospinal tract?
•main function is mediation of reflex head movements in response to vestibular stimuli. It helps adjust the position of the head in response to postural changes
What is the origin and route of the medial (pontine) reticulospinal tract?
- origin - pontine reticular formation
* descends to all levels of the spinal cord
What is the function of the medial (pontine) reticulospinal tract?
Facilitate muscle tone of lateral extensors via the gamma motor neuron loop
Summarize the gamma motor neuron loop. (this is in case you have forgotten)
Stimulation of gamma motor neurons produces stretch on muscle spindles. These activate type Ia fibers, which synapse on alpha motor neurons to produce muscle tone
What is the origin and route of the lateral (medullary) reticulospinal tract?
• origin - medullary reticular formation
Terminates at all spinal cord levels
What is the function of the lateral (medullary) reticulospinal tract?
Excites flexors, inhibits extensors
The lateral and medial reticulospinal tracts have opposing functions. Which excites extensors and inhibits flexors?
medial excites extensors, inhibits flexors.
Lateral is opposite
What is the function of the reticulospinal system?
can modulate reflex action during movement
What is the overall function of the reticulospinal tract?
Muscle tone
What is the overall function of the vestibulospinal tract?
Posture and balance
True or false: the reticulospinal tract is heavily influenced by projections from the cortex via cortico reticulo tract
True–integrates vestibular and other sensory input with motor commands from cerebral cortex
What is the origin and route of the the tectospinal tract?
Origin = superior colliculus Route = projects to cervical spinal cord
What is the function of the tectospinal tract?
Reticulospinal tracts important in coordinating head and eye movements
(the “look that way” reflex)
What is the function of the superior and inferior colliculi?
Superior = visual integration and reflexes
Inferior = auditory integration and reflexes