Physiology 2130 Lecture Notes - Lecture 6: Endoplasmic Reticulum, Myofilament, Neuromuscular Junction
17 Nov 2017
School
Department
Course
Professor
Document Summary
Skeletal muscle is striated: cause by the arrangement of thin and hick myofilaments, range in size from 1mm-12cm. Sarcolemma: cell membrane of a muscle cell. In the relaxed muscle - tropomyosin is situated so that it partially covers the myosin binding sits on the actin molecule: troponin. Events that occur: when myosin binds to actin - a crossbridge is formed, myosin changes shape and a power stroke occurs, actin slides past myosin, resulting in the shortening and contracting of the sarcomere. Neuromuscular junction (nmj: the point of contact between the motor nerve and the muscle cell, neuromuscular transmission. Similar but different to the chemical synapses of the nervous system. Voltage gated ca channels open and ca flows into the axon terminal. Ca triggers synaptic vesicles to fuse to the terminal releasing ach. Ach diffuses across synaptic cleft to the end plate of the muscle cell membrane. Act binds to receptors on chemically gates channels and channels open.
