BMS 870 Lecture Notes - Lecture 20: Golgi Tendon Organ, Nmda Receptor, Nociception
24 Dec 2017
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Document Summary
Ach released from axon terminals of alpha motor neurons. Ach produces epsp in postsynaptic membrane due to activation of nicotinic ach receptors. Epsp opens vg na+ channels = ap fires: excitation-contraction coupling - ap triggers ca2+ release from organelle = contraction. Relaxation when ca2+ lvls lowered by reuptake into organelle. How activity of motor neuron itself is controlled. Proprioception from muscle spindles: muscle spindles - deep in skeletal muscles; fibrous capsule that contains specialized skeletal muscle fibers. Swollen middle - group ia sensory axons (thickest and fastest) wrap around muscle fibers of spindle, an example of proprioceptors. Muscle spindles send sensory feedback through sensory ia axons (stretch receptor). Bms 870 page 2: ia axons enter spinal cord via dorsal roots, branch, form excitatory synapses w/ both interneurons and alpha motor neurons of ventral horns. Single ia axon synapses on almost every alpha motor neuron in the pool innervating the same muscle that contains the spindle.
