1. Types of Muscle, structure and Function

2. Types of muscle 3 General types 1) Smooth (visceral) muscle
Loosely associated fibers
Peristalsis
Found in dig. tract, lungs, arteries

3. Cardiac Muscle Tightly associated fibers
Gap junction and intercalated discs allow for quick exchange between cells
Found only in the heart

4. Skeletal Muscle Tightly associated fibers
Responsible for moving the skeleton
Found everywhere in the body attached to skeleton

5. Structure of Skeletal Muscles
Long thin fibers of sarcomeres connected end-to-end
Fibers bundled into fascicles

6. Sarcomere

7. Sarcomere Basic unit of contraction Sarcolemma surrounds it
Actin – thin filament
Mysosin- thick filament
Tropomyosin covers myosin clubs to prevent bonding during relaxation

8. How contraction occurs
Brain triggers muscle to contract
Message travels down nerve
Crosses synapse and hits sarcolemma

9. Next…. Sarcolemma releases Calcium ions into sarcomere
Ca binds with troponin
Triggers tropomyosin to move

10. Contraction begins
With tropomyosin out of the way, myosin clubs attach to actin filament
Forms cross bridges

11. Finally… ATP binds to cross bridge Causes club position to move
Pulls actin fiber with it
Shortened sarcomere = contraction

12. After contraction ATP is required to break bonds and relax muscle
Rigor mortis