General Flashcards
What does tetanus toxin do?
Inhibits glycine release causing prolonged contraction of the muscle (spasm)
What are Renshaw cells?
Inhibitory neurones that mediate negative feedback by releasing glycine onto alpha motor neurones in response to excitation of these neurones thus inhibiting firing. Also causes contraction of synergistic muscles
What does Ib and Ia do?
Ia conveys sensory stretch information the muscle spindle to the spinal cord whereas Ib connect conveys sensory stretch information at higher threshold from the Golgi tendon organs to the spinal cord
What do gamma motor neurons do?
Contract the spindle so that muscle contraction can be more sensitively regulated
Where does the corticospinal tract decussate?
At the junction of the medulla and spinal cord
What are the different fibres of the corticospinal tract?
Primary motor cortex, PMC, SMA (supplementary motor area), PPC (posterior parietal cortex)
How does the primary somatosensory cortex operate in a motor capacity?
Sends down fibres to filter irrevelant sensory information
What does the pre-motor cortex do?
Planning of intended movements
What does the supplementary motor area do?
Coordinate voluntary movements
What does the posterior parietal cortex do?
Integration of other sensory information
What is apraxia?
Inability to produce a specific motor action although understanding is there
What types of apraxia are there?
Ideomotor (cannot execute although understands), ideational (cannot conceptualise order)
What isBrown Sequard syndrome?
Lesion in one lateral or half of the spinal cord
What are the symptoms associated with Brown Sequard Syndrome?
Ipsilateral hemiplegia with contralateral loss of pain and temperature senations
Causes of Brown Sequard Syndrome?
MS, trauma, cancer, degenerative disorders etc
