HN220 Chapter Notes - Chapter 12: Endoplasmic Reticulum, Sarcolemma, Myofibril
Document Summary
Connected to at least two bones (some exceptions: some connected to the skin, cartilage or to other muscles) Muscles are connected to bones via tendons transmit force from muscles to bone. Structure at the molecular level: thick and thin filaments (exist in 2:1 ratio) Myofibrils are composed of sarcomeres: each sarcomere is bordered by z- lines or m- lines, a bands, h zone are the lighter portion inside the a bands. 12. 2 the mechanism of force generation in muscle. The regular arrangement of thick and thin filaments is the key to muscle contraction. Crossbridge cycles: how muscles generate force: the mechanism that drives the sliding of the thick and thin filaments past each other = cross bridge cycle. Excitation- contraction coupling: how muscle contractions are turned on and off: when a muscle cell receives input from a motor neuron, the cell depolarizes and fires an action potential that then stimulates contraction.
