HES 319 Lecture Notes - Basal Lamina, Focal Adhesion, Motor Unit
Document Summary
Relaxation causes by resequestration of calcium in sr. Tetanic force caused by lack of time all calcium cannot be resequestered between twitches. Classical model all force of muscle applied at end where it connects to tendon. The contractile filaments (actin, myosin) are supported by a complex array of structural proteins that serves to transmit the force of the sarcomere to the tendon. These proteins are ubiquitous (everywhere), provide scaffold, transmit force to outside of cell. Costamer junction between sarcolemma and z lines. Integrins link the extracellular matrix and cytoskeleton at focal contacts. Focal contacts are dynamic structures determining the transduction of stress to intracellular signaling. Extracellular connective tissue that makes up the rest of muscle. Number of muscle fibers / number of alpha motor axons. In a muscle, innervation number varies exponentially within the population of motor units. For example, the innervation number in a hand muscle with 120 motor units varies from 21-1770.
