| A | B |
|---|
| What is the portion of the myofibril that is located between two Z lines? | Sacromere |
| What are the flattened tubules that are part of a triad and surround the myofibrils in the muscle fibers? | T Tubules |
| What membrane surrounds each muscle cell? | Sarcolemma |
| A muscle at rest can be stimulated to contract by what? | Threshold Stimulus |
| When a muscle is sufficiently stimulated, it will react with an "___ or ___" response. | All or none |
| What two chemicals are closely associated wiht actin? | Tropomyosin and Troponin |
| What neurotransmitter is released by a neuron into the synapse at a neuron end plate? | acetycholine |
| Muscle fibers are sub-divided into functional units called what? | Myobrils |
| When the muscle fiber is at rest, the cell's sarcoplasmic reticulum has protein transport molecules that actively pump calcium into what? | Cisternae |
| Why doesn't smooth muscle have any striations? | Because its filaments are not arranged as organized as striated muscle. |
| When a muscle completes a contraction, ATP is used to do what to myosin cross-bridges? | The bridges move to a "cocked position" position. |
| Name the two types of filaments found in the sarcomere. | Myosin (thick filament) and actin (thin filament) |
