Acetylcholine: Chemical neurotransmitter in the brain and PNS.
Actin: Protein component of microfilaments; form thin filaments in skeletal muscles and produce contractions of all mucles through interaction with thick filaments.
Cholinesterase; Enzyme breaks down and inactivates ACh.
Cardiac muscle: Muscle that never gets tired. It is found in the heart.
Extensor: Pushes away from the body.
Fatigue: When the muscle gets tired because it rans out of oxygen.
Flexor: Pushes toward the body.
Ligament: Dense band of connective tissue fibers that attach one bone to another.
Muscle fiber: Tiny fibers of muscle that bunch together and contract.
Myofibril: Organized collections of myofilaments in skeletal and cardiac muscle cells.
Myosin: Protein component of the thick myofilaments.
Skeletal Muscle: A contractile organ of the muscular system.
Smooth muscle: Muscle tissue found in the walls of many visceral organs; charactized as nonstriated, involuntary muscle.
Tendon: A collagenous band that connects a skeletal muscle to an element of the skeleton.
