Lateral corticospinal tract
True or false? The lateral corticospinal tract is the major ascending motor pathway that controls voluntary movement of body.
False. It is the major descending motor pathways that controls voluntary movements of the body
T/F. The function of the anterior corticospinal tract is to control the trunk
True.
Upper motor neurons from which cortical region form the lateral corticospinal tract?
Primary motor cortex (medial)
What is a motor unit?
A lower motor neuron and all the muscle fibres it innervates.
What are reflexes regulated by?
Upper motor neuron input
The major motor pathways of this tract involves two neruons which are termed ________________ and ________________?
Upper motor neurons and lower motor neurons
What is the origin of the reticulospinal tract?
Brainstem
Fill in the blank: The ________ and _________ motor cortex are involved in higher order motor processing and have reciprocal connections to the ______ motor cortex
1) premotor
2) supplementary
3) primary
Where are the cell bodies of lower motor neurons located?
Anterior grey horn of the spinal cord
In UMN lesions, reflexes are ___________.
Increased
In an axial brain slice, the internal capsule appears as 3 parts. Named them.
1) Anterior limb
2) Posterior limb
3) Genu
Name 1 medial pathway responsible for keeping the head balanced on shoulder as the body navigates through space and head turns to stimuli
Can give one of two answers: vestibulospinal pathway or tectospinal pathway
-externally initiated with guided movements = premotor cortex
-internally generated sequences of movements = supplementary cortex
1) UMNs from descending motor pathways
2) Spinal interneurons (inhibitory)
3) Sensory neurons (DRG)
Fill in the blank: Regarding the Golgi tendon reflex, the _______________ in tendon detects stretch
1b sensory afferent
The cell bodies of __________ [3 words]_____________ are found the grey matter of the _______________[2 words]_______ and their very long axons project caudally through the large fibre bundles of the _________[2 words]__________, which narrows into the internal capsule.
1) upper motor neurons
2) precentral gyrus
3) corona radiata
What descending motor pathway has an origin in the brainstem and is a lateral (or dorsolateral) division?
Rubrospinal
Name 3 descending motor pathways that have an origin in the motor cortex.
1) corticospinal (lateral)
2) corticospinal (anterior)
3) corticobulbar
Muscle contraction force can be increased by? Name 2 ways (regarding LMNs)
1) Increasing LMN firing rate
2) recruiting more LMNs
What is the function of the golgi tendon reflex?
To protect against overly large damaging forces
The fibres of the corticospinal tract continue their descent through what 3 structures?
1) cerebral peduncles (basis pedunculi)
2) ventral pons
3) medullary pyramids
Name the pathways with the following functions respectively: 1) backup for corticospinal tract, movement velocity, learned movements 2) modulate anti-gravity reflexes of the spinal cord; automatic posture and gait
1) rubrospinal tract
2) reticulospinal tract
The premotor and supplementary motor cortices are both within what Brodmann area?
Brodmann area 6
Describe the following regarding LMN lesions (must be precise):
1) muscle wasting?
2) fasciculations?
3) tone?
4) clonus (spasms)?
5) reflexes?
6) plantar response?
1) Muscle wasting? Severe
2) Fasciculations? Maybe
3) Tone? Reduced
4) Clonus (spasms)? Absent/unsustained (<3 beats)
5) Reflexes? Depressed/absent
6) Plantar response? Downgoing (normal)
Fill in the blanks: Regarding the myotatic or stretch reflex, _____________________ fibre from muscle spindle detects muscle stretching when _______________________
1) 1a sensory DRG fibre
2) more weight is added.