Pyramidal System Flashcards
Whta do projection fibres (UMNs) connect
Cortices to other brain structures and spinal cord
What are Pyramidal tracts
Sub-population of UMNs that produce movement
Where do pyramidal tracts originate and where do they go
Originate in primary motor cortex and converge to first form the internal capsule before continuing on through the midbrain (cerebral peduncles which are Mickey’s ears), brain stem and spinal cord
What does the Internal capsule separate
Caudate nucleus
Putamen
What does the Internal capsule contain
Association fibres
Pyramidal tracts
Regulates movement
What makes up the pyramidal tracts
Corticobulbar and Corticospinal tracts
Where do the pyramidal tracts originate
Layer V of the primary motor cortex
Where does the COrticobulbar tract pass through an then terminate
Passes through cerebral peduncles
Terminates in brain stem
What movement does the corticobulbar tract produce
Head, neck and face
What is the course of the corticospinal tract
pass through cerebral peduncles
Then medulla
Lateral- crosses over
Ventral-remains on sane side
Go to spinal cord and synapse with lower motor neurons
What is Dorsal horn of spinal cord usually associated with
ascending sensory systems
What is the Ventral horn of the spinal cord usually associated with
descending motor systems
Where are the areas of the spinal cord which control muscles of the limbs and digits
More laterally
where are areas of the spinal cord which control muscles near the trunk
More medially
Symptoms of UMN damage
Muscle weakness and/or stiffness
Increased muscle tone (hypertonia)
Exaggerated stretch reflexes and clonus (involuntary contractions), or spasticity
symptoms of LMN damage
Muscle weakness
decreased muscle tone
Inhibited stretch reflexes and spontaneous firing that cause individual muscle fibre contractions and potentially switching
What is Amyotrophic lateral sclerosis
Degeneration of UMNs and LMNs
What is Primary lateral sclerosis
slow degeneration of corticospinal tract
begins as weakness and stiffness of the legs that causes balance and walking problems
What is Pseudobulbar palsy
Degeneration of the corticobulbar tract.
Facial paralysis, including the tongue, persistent dribbling or difficulty with speaking, chewing and swallowing
What is Progressive muscular atrophy
Degeneration of the LMNs
Begins as weakness and stiffness of the hands that spreads to the lower body and muscles lose tone
What is Multiple sclerosis
Autoimmune disease that attacks the myelin and can produce symptoms of UMN and LMN syndromes
Symptoms of MS
tingling in legs Fatigue Balance Coordination problems Blurred vision Difficutiess speaking or swallowing
What do the fibres of the corticobulbar tract synapse with
some cranial nerves in the brainstem
What do the fibres in the cortiospinal tract synapse with
They cross over to the other side of the body and synapse with the LMNs that innervate muscles
