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

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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
http://www.ib.bioninja.com.au/higher-level/topic-11-human-health-and/112-muscles-and-movement.html

2 Major Disorders that Can Occur In The Muscular System