Flashcards in Descending tracts Deck (29)
Where in the brain do the pyramidal tracts originate?
Are the pyramidal or extra pyramidal tracts responsible for voluntary control of movement?
Where in the brain do the extrapyramidal tracts originate?
Are the pyramidal or extra pyramidal tracts responsible for involuntary control of musculature such as muscle tone, balance, posture and locomotion.
Are there synapses in the descending pathways?
No. At the termination of the descending tracts the neurones synapse with a lower motor neurone.
What two structures does the internal capsule run between? Is it made of white or grey matter?
White matter pathway.
Located between the thalamus and the basal ganglia
What happens to the fibres of the lateral corticospinal tract when they get to the medulla?
The decussate and then descend into the spinal cord.
What pathway controls fine precise movement of the distal lib muscles ( eg fingers)
Is it the fibres of the lateral or anterior corticospinal tracts which cross at the pyramids of the medulla?
Lateral. The anterior corticospinal tract remains ipsilateral until the ventral horn of the spinal cord.
What horn of the spinal cord do upper motor neurones synapse with the lower motor neurones?
If there is damage to the corticospinal tract will the paralysis be of the contralateral or ipsilateral side?
Is it the fibres of the lateral or anterior corticospinal tracts which cross at the ventral horn of the spinal cord?
Anterior. The lateral fibres have already crossed at the medulla.
What is a capsular stroke. Why is this relevant to the motor pathways?
When the internal capsule is damaged from compression by a haemorrhagic bleed. These could cause a lesion of the descending tracts as the upper motor neurones travel through the internal capsule.
What parts of the body does the corticobulbar tracts supply?
Musculature of the head and neck.
Describe the route taken in the corticobulbar tracts?
1. Arise from the primary motor cortex
2. The fibres converge and pass through the internal capsule to the brainstem.
3. The neurones then terminate of the motor nuclei of the cranial nerves.
4. Cranial nerves then carry motor signals to the face and neck.
What are the four extrapyramidal tracts?
Where do the extrapyramidal tracts arise from?
The brain stem
Where does the vestibulospinal tract start?
Vestibular nuclei in the medulla.
What is the function of the vestibulospinal tract?
To control balance and posture (Innervates anti gravity muscles - flexors of the arm, extensors of the leg)
Do the fibres of the vestibulospinal tract remain ipsilateral or cross to become contralateral?
Where does the medial reticulospinal tract originate and what does it do?
Facilitates voluntary movements and increases muscle tone
What does the lateral reticulospinal tract do and where does it originate?
Inhibits voluntary movements and reduces muscle tone.
Where does the rubrospinal tracr originate?
The red nucleus in the midbrain.
What does the tectospinal tract do?
Coordinates movements of the head in relation to visual stimuli.
List the 5 cardinal signs of an upper motor neurone lesion
4. Babinski sign
5. Muscle weakness
What are the symptoms of damage to the extra pyramidal tracts?
Do 1st generation anti psychotics result in pyramidal or extra pyramidal side effects?
What symptom would you get if there was a lesion of the upper motor neurones for the right hypoglossal nerve?
Deviation of the tongue to the left