27 DISEASES OF MOTOR UNITS Flashcards
Define monoplegia
Paralysis of a single limb
Define hemiplegia
Paralysis on one side of the body
Define paraplegia
Waist down paralysis
Define quadraplegia
All four limbs paralysis
Define paresis
Weakness
What are the three abnormalities of muscle tone
Hypertonia (UMN), hypotonia (LMN), rigidity (basal ganglia)
Describe ataxia
Lack of voluntary control/ coordination of muscles
Define dysmetria
Lack of coordination of movement, undershoot/ overshoot. A form of ataxia
What are four categories of involuntary muscle movement
Spasm (cramp), epileptic fit, tremor, dyskinesia
Define dyskinesia
Involuntary muscle movements
What are the words used to describe the type of lesion and timing of lesion
Focal/ diffuse
Acute/ chronic
Where are cell bodies for motoneurons found
In lamina 8 and 9 of the spinal cord (spinal nerves), brainstem (cranial nerves)
What are the two types of motoneurons
Alpha- extrafusal muscle fibre, generation of force
Gamma- intrafusal muscle fibres, determine sensitivity of muscle spindles
What is the motor unit made up of
The alpha motoneuron and the muscle fibres it innervates
Name the descending tracts that converge on alpha motoneurons
Corticospinal tract Corticobulbar tract Vestibulospinal tract Reticulospinal tract Tecto spinal tract
Two non motor tract things that synapse with alpha motoneurons
1a afferent fibres from muscle spindles.
Interneurons (excitatory/inhibitory)
What is disorder of the muscle fibre called
Myopathy
What is disorder to the motoneuron called
Neuropathy
List location of lesions
Muscle fibres Neuromuscular junction Lesion that affects transmission in the axon Axotomy Cell body of neuron
Define muscular dystrophy
A group of inherited disorders characterised by deficits in muscle proteins leading to wasting/ weakness. Includes Duchennes muscular dystrophy, myotonic muscular dystrophy
Describe the most common MD in children
Duchennes MD, X linked so only in boys mild symptoms in girls. Abnormal gene for protein dystrophin used in cell membranes
Describe the most common MD in adults
Myotonic muscular dystrophy. Onset 3rd decade. Wasting, weakness of muscles. Myotonia (delayed relaxtion) CTG repeats in chromosome 19 coding for myotonin protien. Inherited dominant.
Describe myasthenia gravis
Autoimmune condition. Immune system attacks proteins involved in Ach receptors, less synaptic transmission.
Describe the mechanism of action of botulism toxin
Reduces Ach release through proteolysis of membrane proteins involved in the release of Ach. Has non muscle effects due to action on Ach release in autonomic nervous system- dry mouth, postural hypotension
Describe Wallerian degeneration
Loss of synaptic transmission, axons degenerate after the lesion within days due to loss of axon survival factor, degeneration in distal parts of the neuron cell body ok. Axon regeneration occurs facilitated by schwann cells
Name two peripheral neuropathies
Diabetic neuropathy (hyperglycemia causes damage to the small capillaries supplying nerves). Guillian Barre syndrome- autoimmune causing immune attack of myelin.
Name symptoms of lower motoneuron diseases
Atrophy muscles
Weakness/ paralysis
Depressed or abolished reflexes
Fascinations (coarse twitches, sign of muscle denervation due to activation of individual motorunits)
Fibrillations (discharge of single muscle fibres)
No spasticity/ babinskis reflex
