Muscular System
Moves The Human Body
Muscle Tissue
Cardiac Muscle: hows some of the characteristics of smooth muscle and some of skeletal muscle tissue, differ from striated muscle in the following aspects: they are shorter, the striations are not so obvious
Skeletal Muscle: the most abundant tissue in the vertebrate body, These muscles are attached to and bring about the movement of the various bones of the skeleton
Smooth Muscle: made up of thin-elongated muscle cells, fibres, interlace to form sheets or layers of muscle tissue rather than bundles
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/muscle.htm
How Skeletal Muscle Contracts
- An action potential from a motor neuron triggers the release of Ca2+ ions from the sarcoplasmic reticulum
- Calcium ions expose the myosin heads by binding to a blocking molecule (troponin complexed with tropomyosin) and causing it to move
- The myosin heads form a cross-bridge with actin binding sites
- ATP binds to the myosin heads and breaks the cross-bridge
- The hydrolysis of ATP causes the myosin heads to change shape and swivel - this moves them towards the next actin binding site
- The movement of the myosin heads cause the actin filaments to slide over the myosin filaments, shortening the length of the sarcomere
- Via the repeated hydrolysis of ATP, the skeletal muscle will contract