Muscular system

The thick filaments in muscle fibers are called __________, and the thin filaments are called_____________

• Myosin, actin

• Actin, myosin

• Myofibril, actin

The type of muscle that is striated and voluntary is

• Cardiac

• Skeletal

• Smooth

When the triceps ___________, the elbow straighten

• Contracts

• Relaxes

When the biceps contracts, the elbow ____________

• Straighten

• Bends

The neurotransmitter that carries nerve impulses across the synapse to the muscle is

• Calcium

• Actin

• Acetylcholine