BIOB34H3 Lecture Notes - Tymbal, Parvalbumin, Endoplasmic Reticulum
Document Summary
Motor unit- a single motor neuron and all the muscle fibers in it. In vertebrates, not true in invertebrates, every muscle cell only get innervated by only one muscle neuron. All come down to the idea that the total force a muscle can produce depends upon to total number of myosin heads that are going through cross-bridge cycling. One motor unit = there are fewer myosin heads acting. More motor units = more myosin heads, greater total force. This is due to the muscle changing shape that contracts. When a muscle contracts, the length gets shorter and the width increases. This can be used to find problems with muscles. Listen to the sounds and you can find muscle disorders because they cause changes in the sounds the muscles make. Human hearing range is between 20-20000 hz (cycles per second: when you clench your fist, there is at least 20 vibrations occurring to produce that sound (contract 20 times)
