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Meagan Grants Muscle


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.
Created by: meagangrant



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