BME Seminar Series: Yingxin Gao, Ph.D.

The Role of the Extracellular Matrix on Lateral Transmission of Force in Skeletal Muscle

Assistant Professor, Mechanical and Aerospace Engineering, Cornell University

Abstract

Skeletal muscle comprises the active structure – muscle fiber, and the passive structure – the Extracellular Matrix (ECM), which is the key structure that integrates the muscles fibers into a whole muscle. The ECM includes endomysium, perimysium and epimysium, which surround a single muscle fiber, a fascicle and the whole muscle, respectively. It was generally believed that muscle strength is to some extent related to muscle mass. However, for some muscles, there is no close correlation between loss of muscle mass and loss of muscle strength. This can not be explained by the assumptions that muscle is a scale-up of single muscle fibers. Morphological studies have shown that many muscles have series-fibered structure, i.e., the muscle fibers end within muscle fascicles without reaching a myotendinous junction (MTJ). Therefore, in series-fibered muscle, the force generated by individual fiber has to be transmitted to adjacent muscle fibers through the ECM along the length of muscle fibers. This transmission is defined as lateral transmission of force. In this talk, a micromechanical model used to describe the structure-function relationship of the ECM will be presented, followed by a discussion on the mechanisms of lateral transmission in skeletal muscle, and the role of the ECM on this transmission mechanism.