| A | B |
|---|
| Actin | A protein in a muscle fiber that, together with myosin, is responsible for contraction and relaxation. |
| Antagonist | A muscle that acts in opposition to a prime mover. |
| Aponeurosis | A sheetlike tendon by which certain muscles are attached to other parts. |
| Fascia | A sheet of fibrous connective tissue that encloses a muscle. |
| Insertion | The end of a muscle that is attached to a movable part. |
| Motor Neuron | A neuron that transmits impulses from the central nervous system to an effector. |
| Motor Unit | A motor neuron and the muscle fibers associated with it. |
| Myofibril | One of the contractile fibers found within muscle cells. |
| Myosin | A protein that, together with actin, is responsible for muscular contraction and relaxation. |
| Neurotransmitter | A chemical substance secreted by the terminal end of an axon that stimulates a muscle fiber contraction or an impulse in another neuron. |
| Origin | The end of a muscle that is attached to a relatively immovable part. |
| Oxygen Debt | The amount of oxygen that must be supplied following exercise to convert the accumulated lactic acid to glucose. |
| Prime Mover | A muscle that is mainly responsible for a particular body movement. |
| Recruitment | Increase in the number of motor units activated as the intensity of stimulation increases. |
| Synergist | Muscle that assists the action of a prime mover. |
| Threshold Stimulus | The level of stimulation that must be exceeded to elicit a nerve impulse or a muscle contraction. |
| Neuromuscular Junction | The connection between the nerve fiber and muscle fiber. |
| Sarcomere | The strucural and functional unit of a myofibril. |
| Sarcoplasmic Reticulum | A membranous network of channels and tubules within a muscle fiber. |
| Transverse Tubule | A membranous channel that extends inward from a muscle fiber membrane and passes through the fiber. |
| Motor End Plate | A specialized region of a muscle fiber where it is joined by the end of a motor nerve fiber. |
| Acetylcholine | A substance sectreted at the axon ends of many neurons which transmits a nerve impulse across a synapse. |
| Cholinesterase | An enzyme that causes the decomposition of acetylcholine. |
| Hemoglobin | A pigment of red blood cells responsible for the transport of oxygen. |
| Myoglobin | A pigmented compound found in muscle tissue that acts to store oxygen. |
| Myogram | A recording of a muscular contraction. |
| Latent Period | Time lapse between the application of a stimulus and the beginning of a response in a muscle fiber. |
| Tetany | A continuous, forceful muscular contraction. |
| Peristalsis | Rhythmic waves of muscular contraction that occur in the walls of various tubular organs. |
| Skeletal Cardiac Smooth | Types of Muscle Tissue |
| Major Functions | Provide forces that cause body movement, maintain posture, and provide body heat |
| Epimysium | Fibrous connective tissue that surrounds the entire muscle |
| Perimysium | Connective tissue which fills the spaces between the fascicles |
| Endomysium | Connective tissue which surrounds the fascicles |
| Fascicle | Bundle of muscle fibers |
| Skeletal Muscle Fiber | Single, multinucleated cell which contracts when stimulated |
| Sarcolemma | muscle fiber's cell membrane |
| Sarcoplasm | Muscle fiber's cytoplasm |
| A Band | Dark striations; location of myosin filaments |
| I Band | light striations; location of actin filaments |
| Z line | attachment point of actin filaments at end of I Bands |
| ATP | Energy source for muscle contraction |
| Creatine phosphate | Regenerates ATP from ADP |
| All-or-none response | Muscle fiber always contracts to the fullest extent |
| Twitch | A single contraction that lasts only a fraction of a second |
| Muscle Tone | Response to nerve impulses originating repeatedly from the spinal cord, traveling to small numbers of muscle fibers within a muscle. |
| Skeletal Muscle Contraction | Acetylcholine released, diffuses across synapse, muscle fiber membrane stimulated, calcium ions diffuse into sarcoplasm, linkages form between actin & myosin, actin filaments slide inward |
