BIOL 207 Study Guide - Final Guide: Alpha Motor Neuron, Extrafusal Muscle Fiber, Gamma Motor Neuron
Document Summary
# of muscle fibers contracting: graded contraction, contraction of entire muscle can vary, all-or-none, contraction of individual muscle fibers, recruitment: 1. increased in the # of motor units that are activated: flexor, agonist (biceps) primary mover, should be contracted; antagonist (triceps) opposes mover, should be relaxed, extensor, agonist (triceps) antagonist (biceps) 2. flexion: when you bring the muscle closer to the body, extension, when you extend the muscle away from the body, agonist, primary mover, antagonist, opposes mover, muscle spindle apparatus: 1. functions as a length detector: gamma motor neuron, makes intrafusal fibers tighten, heightens spindle sensitivity. 2. intrafusal fiber: muscle spindle fibers, two types, they insert into tendons and run parallel to extrafusal fibers, spindle fiber, they are responsible for muscle contraction, the spindle can tighten or loosen, sensory neuron: 7. 1, 7. 2 and 7. 3: 7. 1- when you stimulate muscle contraction by electric shock; higher voltage reaches more muscle fibers, so the muscles start to jump more frequently.
