PHGY 209 Lecture Notes - Lecture 33: Neuromuscular Junction, Muscle Tone, Motor Neuron
21 Feb 2018
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Extrapyramidal: originates in primary motor cortex (precentral gyrus) Compact, discrete fiber tract direct to spinal cord. Controls skilled voluntary movements: originates from neurons in brainstem, diffused and indirect: several descending tracts via the brainstem. Resistance of skeletal muscle to stretch; when you pull on a muscle, it tends to pull back. This is caused by the activation of the stretch receptors which cause the muscle to pull back (ex. Normal subject: slight and uniform: muscle tone is affected by the problems in the ns, thus it is an easy and effective way to analyze health of ns. Increases muscle tone below the level of lesion: descending pathways inject a lot of circuitry into the spinal cord which is predominantly inhibitory; if there was spinal damage, the reflexes will become amplified. Brackets below not discussed in class: (neurogenic: motor neuron or axon. The middle layer controls a lot of processes that individuals are unaware of:
