Chapter 15: Disorders of Motor Functions Flashcards
Extensors
muscles that increase the angle of a joint
Flexors
muscles that decrease the angle of a joint
Agonists Muscles
promote movement
Antagonist Muscles
oppose movement
Synergists Muscles
assist the agonist muscles by stabilizing a joint or contributing additional force to the movement
Pyramidal Motor System
- originates in the motor cortex
- provides control of delicate muscle movement
Extrapyramidal System
- originates in the basal ganglia
- provides background for the more crude, supportive movement patterns
Upper Motoneuron Leisons
can involve the motor cortex, the internal capsule, or other brain structures through which the corticospinal or corticobulbar tracts descend, or the spinal cord
Lower Motoneuron Lesions
disrupt communication between the muscle and all neural input from spinal cord reflexes, including the stretch reflex, which maintains muscle tone
Myasthenia Gravis *****
Definition
Cause
- disorder of transmission at the neuromuscular junction that affects communication between the motoneuron and the innervated muscle cell
- autoimmune disease caused by antibody-mediated loss of acetylcholine receptors in the neuromuscular junction
Peripheral Nerve Regeneration
- damage to a peripheral nerve axon: due to injury or neuropathy, results in degenerative changes, followed by breakdown of the myelin sheath and schwann cells
- regeneration factors: proximity to soma, crushing versus cutting
Peripheral Nerve Regeneration
- damage to a peripheral nerve axon: due to injury or neuropathy, results in degenerative changes, followed by breakdown of the myelin sheath and schwann cells
- regeneration factors: proximity to soma, crushing versus cutting
Peripheral Neuropathy
Definition
Results
Involvement
- definition: any primary disorder of the peripheral nerves
- results: muscle weakness, with or without atrophy and sensory changes
- involvement: can involve a single nerve (mononeuropathy) or multiple nerves (polyneuropathy)
Mononeuropathis
cause by localized conditions such as trauma, compression or infections that affect a single spinal nerve, plexus, or pheripheral nerve trunk
Polyneuropathy
involve demyelination or axonal degeneration of multiple peripheral nerves that lead to symmetric sensory, motor, or mixed sensorimotor deficits
Lead Toxicity would result in what condition
Polyneuropathy
Nerve Root Injuries
ruptured intervertebral disk
- sensory deficits
- motor weakness
Cerebellum
- coordination of motor movement
Basal Ganglia
- group of deep, interrelated subcortical nuclei that play an essential role in control of movement
- they receive indirect input from cerebellum and from all sensory systems, including vision, and direct input from motor cortex
made up of the: caudate nucleus, putamen, globus pallidus in the forebrain
Parkinson Disease *****
Definition
Characteristics
Clinical Syndrome
- definition: a degenerative disorder of basal ganglia function that results in variable combinations of tremor, rigidity and bradykinesia
- characteristics: progressive destruction of the nigrostriatal pathway, with subsequent reduction in striatal concentrations of dopamine
- clinical syndrome: parkinsonism
Amyotrophic Lateral Sclerosis (ALS)
- devastating neurologic disorder that selectively affects motor function
- disease typically follows a progressive course, with a mean survival period of 2-5 years from the onset of symptoms
Multiple Sclerosis (MS)
demyelinating disease of the CNS
Spinal Cord Injury *****
- damage to the neural elements of the spinal cord
- etiology: MVAs, falls, violence, sports
- damage to the vertebral column, supporting ligaments and spinal cord
- sensory and motor function
