| Question | Answer |
| circular muscle | are sphinceters, typically found surrounding external body openings |
| action potential | sarcolemma becomes permeable to sodium ions (Na+) and potassium ions (K+), leaving excess of positive ions, allowing Na+ entry; the upset of the electrical current; contraction of the muscle cell; takes just a few thousandths of a second for this process |
| sterno | has sternum attachement site |
| muscle fatigue | muscles used strenuously for a long period of time |
| light and dark bands | light (I) and dark (A) bands give the muscle cell as a whole its striped appearance |
| muscle types | skeletal, smooth, cardiac |
| extension | movement that increases the angle or distance between two bones or parts of the body |
| neuromuscular junction | the joining of nerve and muscle cells |
| sarcoplasm | equivalent of the cytoplasm of the cell; the interior of the muscle cell; sarco=flesh |
| atrophy | wasting away |
| glycoysis | the initial step of glucose breakdown, does not require oxygen; glucose is broken down to pyruvic acid and captured in ATP bonds |
| lactic acid | pyruvic acid generated during glycolysis, converted to help provide strength for working muscles |
| biceps | two origins |
| muscle twitches | single, brief, jerky contractions (not normal) |
| origin | attachment of muscle to the immovable or less movable bone |
| unfused (incomplete tetanus) | state of the muscle before tetanic contraction |
| striated muscle | fibers have obvious stripes; skeletal muscle |
| endomysium | connective tissue sheath enclosing the muscle fiber |
| adductor | action of bringing closer |
| flexor | action of bringing toward or together |
| skeletal muscle cell striations | precise arrangement of myofilaments in the myofibrils, producing the banding pattern in the muscle cells |
| plantar flexion | pointing the foot down so that top surface is farther away from the shin |
| sarcomeres | chains of tiny contractile units that make up the myofibril; boxcar |
| ATP regeneration | creation of creatine phosphate (CP), aerobic respiration, anaerobic glycolysis and lactic acid formation |
| oxygen deficit | oxygen levels drop, causing muscles to become fatigued; ionic imbalance |
| axon (nerve fiber) | long threadlike extension of the neuron; forming junctions with the sarcolemma of a different muscle cell |
| skeletal muscle tissue | skeletal, striated and voluntary; can contract rapidly and with great force but tires easily |
| deltoid | triangular |
| rotation | movement of a bone around its axis |
| ATP | used to power muscle contraction, releasing heat in the muscle; the only energy source to power muscle activity; renewable |
| myo- and mys- | = muscle |
| actin filaments | same as thin filaments |
| fascicle | bundle of fibers |
| tension | actin and mysin myofilaments interacting, thin actic filaments pass the thick myosin myofilaments |
| muscle cell | skeletal muscle cell contracts to its fullest extent, never partially contracts |
| isotonic contractions | myofilaments are successful in sliding movement, muscle shortens, movement occurs |
| unipennate | muscles attach to one side of the tendon |
| function of muscle cells | excitability (responsiveness, irritability), contractility, extensibility, elasticity |
| muscular dystrophy | congenital muscular problem; inherited muscle-destroying disease that affects specific uscle groups; muscles degenerate and atrophy |
| motor unit | one neuron and all skeletal muscle cells |
| aerobic endurance | less fatigue, caused when increased blood supply to the muscles, more oxygen is stored and more mitochondria cells are formed |
| sarcolemma | the muscle husk; the plasma membrane |
| myasthenia gravis | affects muscles during adulthood; difficulty in swallowing and talking, general muscle weakness and fatigue; shortage of acetylcholine receptors; death due to respiratory failure |
| aerobic respiration | supplies 95% of ATP for muscle activity; occurs in the mitrochondria and involves a series of metabolic pathways that use oxygen; requires continuous delivery of oxygen and nutrient fuels to keep it going |
| flexion | movement that decreases the angle of the joint and brings two bones closer toegther |
| muscles | word comes from Mus, meaning little mouse, makes up nearly half of the body's mass; the machines of the body |
| abduction | moving a limb away from midline |
| muscle tone | the state of continuous partial contraction |
| thin filaments | composed of contractile protein actin and regulatory proteins; AKA actin filaments, overlap thick filaments |
| synaptic cleft | the gap between nerve endings and muscle cell membranes, filled with interstitial fluid |
| epimysium | overcoat of connective tissue binding fascicles bundles |
| skeletal muscle fibers | huge, cigar shaped multinucleate cells, largest of the muscle fiber types; can be seen with the naked eye; soft and fragile; thousands of fibers bundled together by connective tissue |
| insertion | attachment of muscle to the movable bone |
| Z disc, M line and H zone | Z is the darker area, H is a lighter central area, H contains tiny protein rods that hold the thick filaments together |
| smooth muscle cell | sincle nucleus, spindle-shaped, arranged in layers; do the housekeeping jobs of the body; does its job tirelessly |
| cardiac muscle | form the bulk of the heart wall; is striated, involuntary; cushioned by small amounts of soft connective tissue arranged in bundles |
| eversion | turning the sole of the foot away from midline |
| circumduction | combination of flexion, extension, abduction and adduction; ball and socket |
| anerobic glycolysis | only 5% of ATP for muscle strength, 2 1/2 times faster; the end result of production of glycolysis and lactic acid |
| bare zone | the lighter color zones of the thick and thin filaments |
| triceps | three origins |
| supination (supine) | lying on the back, face or front upward |
| myofilaments | equivalent of the microfilaments of the cytoskeleton |
| voluntary muscle | the only muscle type subject to concious control |
| mutipennate | fascicles insert into several sides of the tendon |
| synergist | help movement by removing opposing movement; balance the movement |
| fixator | hold something so that movement can be done with no opposition |
| adduction | movement of a limb toward midline |
| flaccid | soft and flabby |
| aponeuroses | sheetlike fibers that attach muscles indirectly to bones, cartilage or connective tissue coverings |
| quadriceps | four origins |
| tetanic contraction (fused)(complete tetanus) | when muscle is stimulated so rapidly that no evidence of relaxation is seen, contraction is smooth and sustained |
| intercalated discs | junctions of muscle fibers |
| myofibrils | long ribbonlike organelles which nearly fill the cytoplasm |
| parallel | fascicles run parallel to the long axis of the muscle; straplike |
| bipennate | fascicles insert into opposite sides of the tendon |
| thick filaments | myosin filament, made mostly of bundled molecules of the protein myosin; contain ATPase enzymes, generating power for muscle contraction |
| body movements | flexion, extension, rotation, abduction, adduction, circumduction |
| tendons | blended epimysium tissue; provide durability and conserve space; tough collagenic fibers |
| myofilaments | threadlike, what causes the banding pattern in the sarcomeres; two types, do not shorten during contraction, slide past each other |
| extensor | action of extending |
| elongated | skeletal and smooth muscle cells, shape of the cell has led to the name muscle fibers |
| longus | long |
| minimus | smallest |
| perimysium | coarse fibrous membrane wrapping sheathed muscle fibers |
| dorsiflexion | lifting up the foot so that top surface is closer to the shin |
| sphincters | sqeezing muscles |
| maximus | largest |
| myosin | bundled molecules of protein |
| fusiform | spindle-shaped muscle with expanded midsection, such as the bicep |
| Duchenne's muscular dystrophy | almost exclusively in boys; disease progresses from extremities upward, affecting head and chest muscles; most die young and of respiratory failure; muscles lack dystrophin |
| sarcoplasmic reticulum (SR) | muscle fiber organelle, specialized smooth endoplasmic reticulum, stores clacium and releases calcium ions into cytoplasm on demand when muscle fiber is stiumlated to contract |
| oxidative phosphorylation | the pathways providing aerobic respiration |
| isometric contractions | myosin myofilaments are spinning their wheels, tension in the muscle keeps increasing; resistance training |
| pennate | short fascicles attach at a slant to a central tendon |
| inversion | turning the sole of the foot to the midline |
| graded responses | different degrees of shortening in response to stimuli; frequency of muscle stimulation or number of cells stimulated |
| antagonist | muscles that oppose a movement |
| smooth muscle | no striations, involuntary, cannot consciously control it; found in hollow visceral organs ie stomach, urinary bladder, etc; visceral, nonstriated, involuntary |
| oblique | at a slant |
| skeletal muscle | maintains posture, stabilized joints, generates heat; accounts for at least 40% of body mass; made up of fascicles |
| cross bridges | myosin heads; link the thick and thin filaments together during contraction |
| acetylcholine (ACh) | the neurotransmitter that stimulates skeletal muscle cells |
| muscle fibers | the elongated fibers of smooth and skeletal muscle |
| rectus | straight |
| opposition | bringing two surfaces together, as in opposing fingers meeting the thumb |
| neurotransmitter | the chemical created when nerve impulses reach the axon terminal |
| creatine phosphate (CP) | direct phosphorylation of ADP; found only in muscle fibers; this type is soon exhausted |
| pronation (prone) | lying on the front, back upward |
| cleido | has clavicle attachment site |
| prime mover | the muscle that has most responsibility for movement |
| convergent muscle | fascicles converge towrd a single insertion tendon; triangular |
