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62 Cards in this Set
- Front
- Back
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The upper motor neurons can receive information from what sources?
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Cerebellum
Basal Ganglion Premotor cortex |
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What pathway will most upper motor neurons use to reach the lower motor neuron?
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The local circuit
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Where can you find upper motor neurons?
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In the brainstem and cortex
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What region will control the skeletal muscles of the body?
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Ventral horn of the spinal cord
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What are the somatic motor nuclei in the brainstem?
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Oculomotor
Trochlear Abducens Hypoglossal (III, IV, VI, XII) |
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What are the branchial motor nuclei in the brainstem?
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Trigeminal (V)
Facial (VII) Ambiguus (IX and X) Spinal accessory nucleus (XI) |
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What is a key function of the cingulate gyrus?
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Expression of emotion (via facial expressions)
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What is the function of the premotor and motor cortex?
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Planning, initiating and directing series of movements in the limbs and eyes
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Where are the upper motor nuclei in the brainstem?
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Vestibular
Reticular Superior colliculus |
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What is the function of the upper motor neurons of the brainstem?
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regulate muscle tone
Orient eyes, head and body with respect to vestibular, somatic, auditory, and visual sensory |
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What are (3) muscle feedback loops?
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Muscle spindle
Golgi tendon reflex Flexion reflex |
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What does the muscle spindle do?
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controls the length of the muscle
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What does the golgi tendon reflex do?
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controls the muscle tension
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What does the flexion reflex do?
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moves you in the event of unpleasant stimulus
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What muscle feedback mechanism is the gamma motor neuron associated?
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Muscle spindle. Connects to 8-10 intrafusal muscle fibers.
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Increasing the activity of the Ia muscle spindle afferent will...
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Increase the activity of the alpha motor neuron, decrease the antagonist muscle response, and restore the muscle length
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Why is the gamma motor neuron important for the muscle spindle reflex?
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Allow information to be gathered about the state of the muscle during contraction.
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What controls the activity of the gamma motor neuron?
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Upper motor neurons
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Where are the golgi tendons located?
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Between the muscle fibers and the tendon
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What stimulus activates the golgi tendon?
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tension
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what is a faster reflex, spindle or golgi tendon?
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Spindle (Ia is fast, Ib is slow)
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What afferents are activated by passive muscle stretch?
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Spindle
Golgi tendon |
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Muscle contraction cause what changes in reflex efferents?
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Decrease in spindle efferents
Increase in golgi tendons efferents |
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If tension becomes too great, which feedback mechanism protects the muscle? How?
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Golgi tendon
Releases tension |
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What reflex pathway is active when you step on a tack? Describe it.
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Flexion reflex
Flexion muscle on ipsilateral side is activated and extensor is inhibited. Opposite on the contralateral side. Reflex allows you to maintain posture. |
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Why can the extensors and flexors of a cat walk correctly on a treadmill when the spinal cord is transected?
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The spinal cord is about to organize and generate sequential movements without cortical input
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Describe possible symptomology of a lower motor neuron syndrome.
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Paralysis
Paresis (weakness) Arefexia Loss of tone Atrophy Fibrillation (twitching) Fasiculation (twitching due to damaged alpha motor neuron) |
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The vestibular nucleus will project into which regions of the spinal cord?
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Lateral and medial
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The vestibular nucleus will receive inputs from what source?
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CN VIII
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What is the principle function of the vestibular nucleus?
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control of axial and proximal limb muscles in posture and balance
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What nucleus controls vestibulo-ocular eye movements while the head in moving?
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Vestibular nucleus
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Describe the origin and region of the spinal cord that is occupied by the reticulospinal tract.
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From the pontine/meduallary reticular formation to the medial spinal cord
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Describe the origin and region of the spinal cord that is occupied by the colliculospinal tract.
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From the superior colliculus to the medial cervical spinal cord and gaze centers.
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What is the function of the colliculospinal tract?
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To orient the head, coordinate saccades, aid in somatosomatic reflex
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The vestibular, reticular, and superior colliculus will primarily project to...
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the medial spinal cord to control axial and proximal limb movements
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The vestibular nucleus receives input from...
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CN VIII
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The reticular formation will receive input from...
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Primary motor cortex via the VCST
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The superior colliculus will receive input from...
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upper body proprioceptors, retina, auditory, olfactory, and frontal eye field.
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What is the output tract for the superior colliculus?
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Colliculus spinal tract
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What is the output tract for the reticular formation?
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Reticulospinal tract
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What is the output tract for the vestibular nucleus?
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Vestibulospinal tract
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What tract is responsible for eye movement while the head is moving?
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Vestibulospinal tract
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What tract is responsible for orientation of the head and saccades?
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Colliculospinal tract
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What tract connects the cortex to the brainstem?
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Corticobulbar
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What tract connects the cortex to the spinal cord?
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Corticospinal
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Indirect pathways to the spinal cord will synapse in which areas of the brainstem?
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Superior colliculus
Reticular formation |
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What are the two division of the corticospinal tract?
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Ventral
Lateral |
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Which component of the corticospinal tract will cross over at the pyramidal decussation?
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Lateral corticospinal tract
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The lateral corticospinal tract carries information from ... to...
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Motor cortex
Limbs and hands |
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The lateral corticospinal tract will give branches to the ...
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gracilis and cuneatus dorsal column nuclei
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The ventral corticospinal tract will give branches to the...
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reticular formation
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The ventral corticospinal tract carries information from ... to...
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Motor cortex to the hip, trunk, shoulder, elbow and neck
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Where can the ventral corticospinal tract cross over?
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in the cord
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The lateral and ventral corticospinal tract will innervate which areas of the cord?
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Lateral does lateral
Ventral does medial |
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What does corticobulbar mean?
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From the cortex to the cranial nerve nuclei
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Facial upper motor neurons travel on which tract?
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Corticobulbar
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What tract will carry upper motor neurons for the innervation of the trunk and limbs?
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Corticospinal
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What portion of the premotor cortex is responsible for responses to external cues?
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Lateral
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What is the medial premotor cortex responsible for?
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internally generated movements
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Overactive stretch reflexes is a sign of what type of lesion?
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Upper motor neuron lesion
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A positive Babinsky sign is a sign of what type of lesion?
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Upper motor neuron lesion
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What is the difference between lower and upper motor syndrome in respect to muscle tone?
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Upper: spastic, increased tone
Lower: atrophy, decreased tone |
