PSYC 106 Lecture Notes - Lecture 15: Neuroimaging, Motor Learning, Actual Size
Document Summary
Skeletal muscles- contract to produce movement: the movement produced is determined by where muscle is attached to bone (tendon- point of attachment, synergistic muscles- muscles that contract and relax; necessary for movement in opposite directions. Extrafusal muscle fibers- exert force through contraction: consist of many individual fibers bound together by connective tissue, myofibril (myofilaments)- smallest component fibers. Consists of interlocking actin and myosin proteins. During contraction, the myosin heads bind to actin and then bend to slide. Intrafusal muscle fibers- involved in sensory feedback filaments past one another which shortens the muscle. Botox- inhibits ach from being released, which stops muscles from contracting: then voltage-gated na+ channels open and an action potential is produced, voltage-gated calcium channels then open, triggering molecular changes that lead to muscle contraction. Innervation ratio- how many muscle fibers are innervated by one alpha motor neuron: a major determinant in the amount of control over movement (lower innervation ratios allow for greater/finer muscle control)
