PHGY 214 Lecture Notes - Lecture 20: Anterior Grey Column, Hyporeflexia, Upper Motor Neuron
8 Dec 2017
School
Department
Course
Professor
Document Summary
Skeletal muscle reflex (lecture 5) nervous reflex = integration of sensory input w an involuntary response motor out ventral, sensory is in dorsal some info still goes up sc. Extrafusal fibres = major contractile fibers, innervated by: alpha motor neurons= Intrafusal fibres form part of sensory apparatus in parallel with extrafusal fibres: wrapped by sensory receptors, missing myofibrils in central portion. = sensory organs that contain (starts stim) modified muscle fibers (intafusals) sensory neurons fire when stretched (when carrying load briefly arm falls w gravity stretching muscle: sensory neurons: 1 detect: change in length and rate (located in middle) 2 detect: change in length (located near sides) Contract top and bottom middle muscle becomes stressed, sends reflex causing extrafusal muscle to contract tendon quadriceps. Golgi tendon organs: detect forces location tendons, when muscles contract, tendons are pulled and gto"s fire, muscle causes inhibition of motor neurons to muscle result= slower contraction as force increases, prevents excessive contraction.
