Descending Tracts Flashcards
Pontine Reticulospinal Tract function? Descends?
Facilitates motor neurons to axial and limb Extensors; IPSILATERAL
Medullary Reticulospinal Tract function? Descends?
Inhibit/ excite motor neurons to cervical muscles and excites motor neurons to back muscles; BILATERALLY
Reticuloformation receies input from motor cortex, cerebellum, and brain stem nuclei. Functions?
Fixing a posture, Stabilization of proximal limb joints so voluntary movement of distal limbs can occur.
Lateral Vestibulospinal tracts terminates _____ in the ventral horn. Effects _____ muscles (maintains blance and upright posture)
Ipsilaterally; antigravity
Does Lateral Vestibulospinal tract cross?
NO
Medial Vestibulospinal tract descends _____ within MLF
Bilaterally
Is Lateral Vestibulospinal tract found in all cord segments?
Yes, ALL
Is Medial Vestibulospinal tract found in all cord segments?
NO; cervical and thoracic levels (maintains head position in response to VESTIBULAR RESPONSE when moving)
Tectospinal tract originates in the superior colliculus of _____
Midbrain
Tectospinal tract crosses in the ______.
Dorsal tegmental decussation
Tectospinal tract terminates in _____ segments.
Cervical cord
Tectospinal tract function?
Reflex head movements in response to visual, auditory, cutaneous stimuli. (TRACKING A VISUAL STIMULUS)
Rubrospinal tract originates in?
Red nucleus of the midbrain
Rubrospinal tract crosses at the ______.
Ventral tegmental decussation
Rubrospinal tract extends to _____ cord in humans. (Not found in all cord segments)
Cervical
Rubrospinal tract function?
Facilatates flexor and inhibits extensor motor neurons. (Flexion)
Descending autonomic fibers originate from _____ and brain stem nuclei.
Hypothalamus
Descending autonomic fibers terminates on _____ neurons
Preganglionic
Aminergic pathways (raphespinal) originate in_____ formation
Reticular
Aminergic pathways (raphespinal) terminates in?
Dorsal horn
Corticospinal tract is part of _____ system
pyramidal
Corticospinal tract originates in? (Many)
Motor, premotor, supplementary, postcentral gyrus, paracentral lobule
Corticospinal tract function?
Provides skill, precision, speed, and agility during voluntary movements.
Corticospinal tract 85-90% cross in the _____ decussation. 10-15% descend uncrossed as ventral corticospinal tract but cross before terminate in gray of cervical and upper thoracic segments.
Pyramidal
Corticospinal tract terminates on ___ and ___ motor neurons and on interneurons.
Alpha and gamma motor neurons
