| A | B |
|---|
| endomysium | a delicate connective tissue sheath |
| perimysium | coarser fibrous membrane to form a bundle of fibers |
| epimysium | connective tissue that covers the whole muscle |
| aponeuroses | attach muscles indirectly to bones, cartilage, or connective tissue coverings |
| sarcolemma | many oval nuclei just beneath a plasma membrane |
| myofibrils | long ribbonlike organelles in a muscle cell |
| sarcomeres | tiny contractile units arranged end-to-end in a myofibril |
| myofilaments | threadlike proteins responsible for muscle contraction |
| myosin | makes up thick filaments |
| actin | makes up thin filaments; the contractile protein |
| sarcoplasmic reticulum | a specialized smooth endoplasmic reticulum |
| acetylcholine | specific neurotransmitter that stimulates skeletal muscle |
| Neuromuscular Junction | Junctions between axon terminals and the sarcolemma. |
| Isotonic Contractions | Contractions in which the muscles shorten |
| Isometric Contractions | Contractions in which the muscles do not shorten |
| Muscle Tone | The state of continuous partial contractions. |
| Isometric Exercises | When muscles are pitted against immovable objects. |
| Origin | The point where muscle is attached to the immovable or least movable bone. |
| Insertion | The point where the muscle is attached to the movable bone. |
| Flexion | A movement that decreases the angle of the joint and brings bones closer together. |
| Extension | Movement that increases the angle of the joint and increases the distance between two bones. |
| Rotation | Movement of a bone around its longitudinal axis. |
| Abduction | Moving a limb away from the midline. |
| Adduction | Movement of a limb toward the body midline. |
| Circumduction | Combination of flexion, extension, abduction, and adduction seen in a ball and socket joint. |
| Dorsiflexion | Lifting the foot to where your toes are closer to your shin. |
| Plantar Flexion | Pointing your toes to the ground. |
| Inversion | Turn sole medially. |
| Eversion | Turn the sole laterally. |
| Supination | Forearm rotates laterally so palm faces anterior. |
| Pronation | Forearm rotates medially so palm faces posterior. |
| Opposition | Action in which you touch your thumb to the tips of your other fingers. |
| Antagonists | Muscles that oppose or reverse a movement. |
| Synergists | Help prime movers by producing the same movement or reducing undesirable movements. |
| Fixators | Hold a bone still. |
| Circular | When fascicles are arranged in concentric rings. |
| Convergent | Fascicles converge toward a single insertion tendon. |
| Parallel | The length of the fascicles run parallel to the long axis of the muscle. |
| Fusiform | Results in a spindle shape muscle with an expanded belly. |
| Pennate | short fascicles attach obliquely to a central tendon. |
