Study Guide Anatomy and Physiology

TheScientificWorldJournal, 2013

Hindawi Publishing Corporation

Background: Current understanding of skeletal muscle contraction is based on the sliding filament theory proposed independently by A.F. Huxley and H.E. Huxley (1954). The sliding filament theory very well explained shortening of skeletal muscle during contraction with reference to a single sarcomere with movement of Z discs toward center of that particular sarcomere. However, when we consider shortening of multiple sarcomeres in a myofibril arranged in series, the sliding filament theory fails to justify the movement of Z discs as each Z disc is being pulled in opposite direction by myosin heads of adjacent sarcomeres. Aims & Objectives: To find out alternate possible mechanism of Z disc movement on either side of A band if movement toward center by both sides is not possible.

Experientia, 1968

Journal of Clinical Pathology, 1978

The Journal of Cell Biology, 1981

A new era in muscle research had its beginning in the early and mid-1950s. The new structural and biochemical techniques that became available to muscle-cell biologists were combined with clever physiological experiments to provide a vigorous and fresh new approach, the hallmark of which has been the understanding of close relationships between function and underlying structure . As a result, striated muscle has become more than a black box containing springs and viscosities and delimited by a membrane with unusual electrical properties. Within a muscle fiber, specific patches of membrane have specific functions in the control of muscle activity, enzymes are suitably located for their functional contribution, and the contractile material is disposed in a highly organized array of interacting filaments and bridges . Springs and viscosities have been moved to the description of muscle contractility at the molecular level . Beyond these successes, what has been learned from muscle is applied to many other biological phenomena, e.g ., excitation-secretion coupling in secretory cells and motility in many kinds of nonmuscle cells .

Journal of Morphology, 1987

The differences in angulation and length observed for the fibers of anatomical muscles may reflect two distinct mechanical requirements: 1) arrangement for pinnation, reflecting an increase in physiological crosssection and 2) arrangement for equivalent placement of sarcomeres, possibly associated with coordination. The observed differences in fiber angulation and length have different effects upon the responses of sarcomeres, specifically on their extent and rate of shortening and on the force they may generate. The basic mechanisms governing these effects and the various arrangements of muscles are reviewed. Fiber length and angulation in the complex M. adductor mandibulae externus 2 of a lizard were measured stereotactically; these values correlate well with the hypothesis that the muscle shows equivalence and demonstrate that angulation for pinnation is less constant. An outline for the study of muscle architecture and function, detailing the kinds of information required to estimate forces and evaluate muscle and fiber placements, is presented.

PLoS Biology, 2004