1. Muscles of the human body:

2. Muscle characteristics:
605 in the human body
Maintains posture
Generate heat
Stabilizes joints
Locomotion
Facial expressions
Manipulation of the environment

3. Three muscle types:
Smooth-uninucleated,involuntary and nonstriated; walls of the blood vessels and hollow visceral organs (stomach and bladder)
Cardiac-uninucleated, involuntary and striated; walls of the heart
Skeletal-multinucleated, voluntary and striated; muscles of the body

8. Terms: Myo-muscle Tendon-connects muscle to bone
Ligament-connects bone to bone
Myotendonous junction-junction where muscle and tendon meets
Muscle attachment-origin-less movable bone; insertion-movable bone
Muscle cells are called muscle fibers

9. Why are muscle cells so strong?
There are many muscle fibers bundled together with connective tissue in muscles

10. Muscle structure:
Muscle fiber (cell)-connective tissue of endomysium-group of muscle fibers covered by perimysium(fascicle)-groups of fascicles covered by epimysium

12. Types of muscle fibers:
Slow twitch-fatigue resistant-contract for a long time-endurance
Fast twitch-fatigue-cannot contract for a very long time-speed

13. Microscopic muscle structures:
Sarcolemma-plasma membrane in muscle cells
Myofibrils-long organelle composed of myofilaments
Sarcomeres-tiny contractile units found in myofibrils

14. Myofilaments: Small protein structures in a banding pattern
Myosin (protein)-thick filament-extend entire length of the A band-forms the cross bridges (golf heads)
Actin (protein)-thin filament

18. Muscle contraction: Muscle sliding filament theory
Calcium is the go signal for contraction
ATP needed for contraction and relaxation

19. Building muscle:
Destroy and break down the muscle fibers-replaced with bigger and better fibers-muscle adapts to stress