Post on 01-Apr-2015
transcript
Types of Muscle, structure and
Function
Types of muscle
►3 General types►1) Smooth (visceral)
muscle► Loosely associated
fibers►Peristalsis► Found in dig. tract,
lungs, arteries
Cardiac Muscle
►Tightly associated fibers
►Gap junction and intercalated discs allow for quick exchange between cells
► Found only in the heart
Skeletal Muscle
►Tightly associated fibers
►Responsible for moving the skeleton
► Found everywhere in the body attached to skeleton
Structure of Skeletal Muscles
►Long thin fibers of sarcomeres connected end-to-end
►Fibers bundled into fascicles
Sarcomere
Sarcomere
►Basic unit of contraction►Sarcolemma surrounds it►Actin – thin filament
►Mysosin- thick filament
►Tropomyosin covers myosin clubs to prevent bonding during relaxation
How contraction occurs
►Brain triggers muscle to contract
►Message travels down nerve
►Crosses synapse and hits sarcolemma
Next….
►Sarcolemma releases Calcium ions into sarcomere
►Ca binds with troponin
►Triggers tropomyosin to move
Contraction begins
►With tropomyosin out of the way, myosin clubs attach to actin filament
► Forms cross bridges
Finally…
►ATP binds to cross bridge
►Causes club position to move
►Pulls actin fiber with it
►Shortened sarcomere = contraction
After contraction
►ATP is required to break bonds and relax muscle
►Rigor mortis