| A | B |
|---|
| skeletal | voluntary muscles |
| smooth | involuntary muscle found in stomach |
| cardiac | involuntary muscle found in heart |
| sphincter | ring of muscles that guards entrances and exits |
| tendons | connect muscles to bones |
| sarcomere | contracting part of a muscle |
| actin | thin myofilament |
| myosin | thick myofilament |
| calcium | mineral that triggers contractions |
| muscle tension | pulling force on a tendon when a muscle is contracting |
| muscle twitch | a brief contraction-relaxation response to a single stimulus |
| incomplete tetanus | normal muscle contractions are a result of this |
| complete tetanus | a charlie horse is a result of this |
| motor unit | a motor neuron and all the muscle cells (fibers) it controls |
| muscle tone | tension in a resting muscle |
| isotonic | type of contraction where the tension (load) on a muscle stays constant |
| isometric | type of contraction in which the length of a muscle stays constant |
| ATP | type of energy needed for muscle contraction |
| muscle fatigue | when a muscle loses ability to contract due to lactic acid buildup |
