Lecture 1 Pt 2 Flashcards
The ___________ is a complex network of structures and pathways that organize, control and execute voluntary movements
sensorimotor system
List all the structures involved in the sensorimotor system
- cortex and UMNs
- subcortical structures: basal ganglia, cerebellum
- brainstem
- LMNs - cranial and spinal nerves
What structure/area of the brain generates neural impulses that control execution of movements
the primary motor cortex
If motor movements are internally driven (initiation, maintenance, inhibition and learning of complex motor behaviours) they are driven by what area of the brain
Supplementary motor area
If motor movements are sensory guided (externally driven) they are driven by what area of the brain?
Premotor cortex
Describe the key aspects of the primary motor cortex
- somatotopically organized
- control voluntary muscles on contralateral side
- # of motoneurons allocated to a muscle depends on the degree of control needed
- Organized in FUNCTIONAL groups
Damage to motor areas in the cortex would likely lead to what type of MSDs
unilateral UMN dysarthria and spastic dysarthria
Damage to broca’s area, left insula or arcuate fasciculus would likely lead to what type of MSD
apraxia of speech
List the divisions of UMNS
- Pyramidal tract (2 subtracts, corticospinal and corticobulbar)
- Extrapyramidal tract
Describe UMNs
- contained within CNS
- originate in the cortex
- terminate @ cranial or spinal nerve nuclei
- include pyramidal and extrapyramidal tracts
- don’t include BG and cerebellar control circuits
What is the function of UMNs?
control voluntary movements (finely controlled, skilled, discrete, rapid)
How many axonal synapses do UMNs have?
1
UMN innervate LMNs on the _______ side of the body
contralateral/opposite
List the UMN effects of damage
- Hypertonia (spasticity)
- Hyperreflexia
- Emotional lability
- Weakness
- Babinski sign
- Spastic or unilateral UMN dysarthria
Define hypertonia - spasticity
an increase in muscle tone due to hyperexcitability of the stretch reflex; characterized by a velocity-dependent increase in tonic stretch.
When analyzing someone’s speech what are the 2 channels from which we get info?
-visual and auditory
Pseudobulbar palsy involves damage where?
in multiple UMNs that feed into multiple cranial nerves
Describe LMNs
- contained within CNS and PNS
- originate in the brainstem and spinal cord
- terminate at the muscle
- carry out UMN commands for voluntary movements
- produce muscle actions in reflexes
- somewhat responsible for maintaining muscle tone
List LMN effects of damage
- hypotonia
- atrophy
- hyporeflexia
- weakness (paralysis)
- fasciculations
- flaccid dysarthria
Bulbar palsy involves damage where?
damage in multiple LMNs
What type of degeneration is present in ALS?
UMN + LMN
What type of degeneration is present in primary lateral sclerosis
UMN
What type of degeneration is present in PSP
UMN
What type of degeneration is present in progressive muscular atrophy?
LMN
What type of degeneration is present in progressive bulbar palsy
LMN
What are common signs in ALS (related to SLP)s?
- Tongue fasciculations, increased jaw jerk, tongue atrophy, dysarthria & dysphagia
- Slowing of speech rate (cardinal sign)
- Decreased intelligibility
What will be the result of a phrenic nerve lesion below c5?
many abdominal and thoracic muscles involved in breathing but diaphragm is ok
What will be the result of a phrenic nerve lesion between C3 and C5?
cause paresis of the diaphragm – will need help with breathing
What will be the result of a phrenic nerve lesion above C3?
paralyzed diaphragm – ventilator
List the relevant muscles for inspiration and expiration
- sternocleidomastoid
- external intercostals
- internal intercostals
- diaphragm
- rectus abdominis
- external oblique
- internal oblique
- transvers abdominus
Where is the CPG that controls respiration located?
brainstem
In order for the cortex to control voluntary breathing, what must be overridden?
- the brainstem respiratory CPG
Describe myasthenia gravis
- An autoimmune disorder in which the body produces antibodies that block ACh receptors at the post-synaptic neuromuscular juncture
- Leads to weakness and fatigue esp. in head and neck
- No atrophy or fasciculations
- Increased weakness with increased use
