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Meagan Grants Muscle
muscles
| Question | Answer |
|---|---|
| 1 What is contractility? | Ability of skeletal muscle to shorten with force. |
| 2 What is excitability? | Capacity of skeletal muscle to respond to a stimulus. |
| 3 What is extensability? | The ability to be stretched. |
| 4 What is elasticity? | Ability to recoil to their original resting length after they have been stretched. |
| 5 What is the skeletal muscle surrounded by? | Epimysium. |
| 6 What connective tissue, located outside of the epimysium, surrounds and seperates the muscle? | Fascia. |
| 7 A muscle is composed of numerous visible bundles called what? | Fasciculi. |
| 8 What is the fasciculi surrounded by? | Perimysium. |
| 9 The fasciculi is surrounded by single muscle cells called what? | Fibers. |
| 10 True or false, the muscles help produce body heat. | True. |
| 11 What is a single cylindrical cell containing several nuclei? | Muscle fibers. |
| 12 What is each fiber surrounded by? | Endomysium. |
| 13 What are myofibrils? | A threadlike structure that extends from one end of the fiber to the other. |
| 14 What are the two mjor kinds of protein fibers? | Actin myofilaments and myosin myofilaments. |
| 15 What is the myofilament that resembles two minute strands of pearls twisted together? | Actin myofilament. |
| 16 What is the myofilament that resembles bundles of minute golf clubs? | Myosin myofilaments. |
| 17 What forms highly ordered units called sarcomeres? | Actin and myosin myofilaments. |
| 18 What is the basic structural and functional unity of the muscle? | Sarcomere |
| 19 What does a sarcomere extend from and extends to? | Z Line. |
| 20 The arrangement of actin and myosin give a what appearance? | Banded. |
| 21 The light area called the I line is on each side of the what? | Z Line. |
| 22 What does the light area consist of? | Actin. |
| 23 The A band extends the length of what? | Myosin. |
| 24 The A band is the what in the sarcomere? | Darker center region. |
| 25 What is the light area inside of the sarcomere? | H Zone. |
| 26 The H zone consists of only what? | Myosin. |
| 27 What type of myofilament is in the center of the sarcomere in the dark staining band? | Myosin. |
| 28 What is the dark staining band called? | M Line. |
| 29 The outiside of the cell membrane is what type of charge? | Positive. |
| 30 The inside of the cell membrane is what type of charge? | Negative. |
| 31 The resting memebrane potential is the what across the membrane? | Charge difference. |
| 32 What changes briefly when the muscle cell is stimulated? | Membrane characteristics. |
| 33 The brief reversal back of the charge is the what? | Action potential. |
| 34 What are motor neurons? | Nerve cells that carry action potentials to skeletal muscle fibers. |
| 35 What enter the muscles and branch? | Axons. |
| 36 What forms a neuromuscular junction? | A branch that connects to the muscle. |
| 37 What is a synapse? | A branch that connects to the muscle near the center of the cell. |
| 38 A single motor neuron and all the skeletal muscle fibers it innervates are called? | Motor unit. |
| 39 True or false. A single motor unit forms a single muscle. | False. |
| 40 An enlarged nerve terminal resting in an indentation of the muscle cell membrane forms what? | Neuromuscular junction. |
| 41 The enlarged nerve terminal is what? | Presynaptic terminal. |
| 42 The space between the presynaptic terminal and the muscle cell is? | Synaptic cleft. |
| 43 The space between the muscle cell and the muscle fiber is? | Presynaptic terminal. |
| 44 Every presynaptic terminal contains what? | Synaptic vesicles. |
| 45 What secretes a neurotransmitter called acetylcholine? | Synaptic vesicles. |
| 46 It diffuses across the synaptic cleft and binds what causing a change in the postsynaptic cell? | Postsynaptic terminal. |
| 47 What does exocytosis do? | Causes the synaptic vesicles to release acetylcholine into the synaptic cleft. |
| 48 The acetylcholine diffuses across the synaptic cleft and binds to the what in the muscle cell? | Receptor molecules. |
| 49 The combination of what two things causes an influx of sodium ions into the muscle fiber? | Acetylcholine and its receptor. |
| 50 What does the influx initiate? | An action potential in the muscle cell causing it to contract. |
| 51 What does the enzyme acetylcholinesterase do? | Acetylcholine released into the synaptic cleft between the neuron and the muscle cell is rapidly broken down. |
| 52 The enzymatic breakdown of the skeletal muscle ensures what? | One action potential in the neuron yields only one action potential. |
| 53 The enzymatic breakdown of the muscle cell ensures what? | One action potential int he neuron yields only one contraction. |
| 54 What occurs as actin myofilaments slide past myosin myofilaments causing the sarcomeres to shorten? | Muscle contractions. |
| 55 What happenes to the muscle when the sarcomere shortens? | Shortens. |
| 56 What is the sliding filament mechanism of muscle contraction? | Sliding of actin myofilaments sliding past the myosin myofilaments during contraction. |
| 57 True or false. The H and I bands shorten, but the A bands do not change in length. | True. |
| 58 Muscle twitch? | A contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers. |
| 59 What level does a muscle fiber have to reach for it to respond to a stimulus? | Threshold. |
| True or false. The point at which the muscle fiber will contract maximally is all-or-none response. | False. |
| 61 Lag phase? | The time between application of a stimulus to a motor neuron and the beginning of the contraction. |
| 62 The time of contraction is called what? | Contraction phase. |
| 63 The time when the muscle relaxes? | Relaxation phase. |
| 64 Tetany? | Where the muscle remains contracted without relaxing. |
| 65 Recruitment? | The increase in number of motor units being activated. |
| 66 Anaerobic respiration? | Without oxygen. |
| 67 Aerobic respiration? | With oxygen. |
| 68 Muscle fatigue? | results when ATP is used during muscle contraction faster than it can be produced in the muscle cells. |
| 69 Isometric? | The length of the muscle does not change but the amount of tension increases during the contraction process. |
| 70 Isotonic? | The amount of tension produced by the muscle is constant during contraction but the length of the muscle changes. |
| 71 Muscle tone? | Refers to constant tension produced by muscles of the body for long periods of time. |
| 72 Fast-twitch fibers? | Contract quickly and fatigue quickly. |
| 73 Slow-twtch fibers? | Contract more slowly and are more resistant to fatigue. |
| 74 Origin? | Most stationary end of the muscle. |
| 75 Insertion? | Is the end of the muscle undergoing the greatest movement. |
| 76 Belly? | Portion of the muscle between the origin and the insertion. |
| 77 Synergists? | Muscles that work together to accomplish specific movements. |
| 78 Antagonists? | Muscles that work in opposition to one another. |
| 79 Prime mover? | One muscle plays the major role in accomplishing the desired movement. |
| 80 What describes a muscles name? | Location, size, orientation of fibers, shape, origin, insertion, and function. |