BIOL 382 Lecture Notes - Lecture 10: Monolayer, Gastrointestinal Tract, Calmodulin
Document Summary
Vertebrates have 8 different genes for myosin ii. Myosin can combine to become a homodimer or a heterodimer. There are 36 combinations for myosin dimers, but different types of muscle cells can only express a subset. Cardiac muscle expresses a and b myosin ii genes. Ex: rabbits (which have a lower heart rate) express b-myosin ii compared to rats which express a-myosin ii. Others differ in interaction with regulatory proteins. Some are expressed at discrete points in development. Adult myofibers are categorized as type i, iia, iib, and iix/d. Fast twitch: iib-myosin ii (faster velocity/ low efficiency) Each myofibers can express a single myosin isoform, but a muscle can be made of myofibers expressing different myosins. It can be as short as 1. 3mm (stapedius) in the ear and. 60cm from the hip to the knee (sartorius). Skeletal muscle is typically made from the fusion of several cells.
