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97 Cards in this Set
- Front
- Back
Three types of muscle tissues?
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skeletal, cardiac, smooth
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Skeletal Muscle
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Striated and voluntary attached to bones
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Smooth Muscle
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involuntary and non striated located in viscera
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Cardiac
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striated and involutary and has intercalated discs forms the wall of the heart, its fibers are arranged similarly to skeletal muscle fibers, cardiac muscle fibers connect to adjacent fibers by intercalated discs which contain desmomes and gap junctions4
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What the 4 functions of the muscle tissue?
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produce body movement, stabilizes, moves substances, and generate heat
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What are the four properties of muscle?
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electrical exitability, contractility, externsibility, elasticity
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Action Potentials (impulses)
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electrial signals that go down the axon and the muscle fibers
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Electrical excitability
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ability to respond to certain stimuli with electrical signals called action potentials
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Contractility
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ability of muscle tissue to shorten when stimulated by an action potential
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Extensibility
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ability of muscle to stretch within limits without being damaged
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Elasticity
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ability for muscle to return to its orginal shape length after extension
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Muscle fibers
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a muscle cell that is multi nucleated
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hypodermis
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seperated the muscle from the skin
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Fascia
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band of dense connective tissue that supports and surrounds muscles and other organs of the body
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Three layers of the connective tissue
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epimysium, perimysium, endomysium
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Epimysium
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circles the entire muscle outermost layer
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Perimysium
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surrounds groups of muscles irregular connective tissues and into fascicles
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Fascicles
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bundles of muscle fibers surrounded by the perimysium
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Endomysium
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separates the individual muscle fibers from one another
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Tendon
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Ropelike and attaches the muscle to the periiosteum of a bone
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aponeurosis
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connective tissue layers that extend as a broad flat sheet example the epicranial on the skull
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Motor Neurons
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a neuron that stimulates the muscle fibers to contract
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Axon
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threadlike process that extends to the skeletal muscle fibers from the bain or spinal cord
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Muscular Hypertrophy
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enlargment of existing muscle fibers
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Muscular Hyperplasia
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increase in the number of muscle fibers
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Muscular atrophy
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decrease in size and strength in the muscle
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Satelite cells
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fuse together to repair muscle fibers to regenerate functional muscle fibers
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Sarcolemma
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the plasma membrane of a muscle fiber
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transverse (T) tubules
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tunnel like invaginations of the sarcolemma that extends toward the center of each musce fiber and filled with intersitial fluid
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Sarcoplasm
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the sarcolemma surrounds this and it is the cytoplasm of the muscle fiber caontains a large amount of glycogen for energy production and myoglobin for oxygen storage
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Myoglobin
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red colored protein that binds oxygen molecules,
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Myofibrils
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contractie element of skeletal muscle extened the entire length of the muscle fiber, contains thick and thin filaments
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Sarcoplasmic Reticulum (SR)
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fluid filled system of membranous sacs , encircles each myofibril
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Terminal Cisterns
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dilated end sacs of SR
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Triad
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one T-tubule and two termina lcisterns
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Thin Filaments
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made of actin in the I band
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Thick Filaments
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made of myosin H zone
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Sarcomeres
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basic functional unit of myofibirls
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A band
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dark middle portion consists primarily of the thick filaments with some thin overlapping the thick ones
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H zone
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is in the middle of the A band and contains thick filaments only
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zone overlap
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wheree thick and thin filaments lie side by side
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I band
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light area and contains only thin filaments
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Z discs
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passes throug hthe center of the i band
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M line
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middle of the sarcomere
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Myosin
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main componet of thick filaments , a contracile protein that pushes or pulls various cellular structures to achieve moevement converts atp to mechanical energy of motion or force
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Actin
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main componet in the contractile protein thin filaments connects to the myosin for the sliding together of the filaments
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tropomyosin
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blocks off myosin binding sites in the thinn filaments
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troponin
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holds tropomyosin in place in the thin filaments
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Titin
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key structural protein, third most plentiful in skeletal muscle,, helps a sarcomere return to its resting length after a muslce has contracted or been stretched
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Dystophin
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a structural protein that links thin filaments of the sarcomere to integral membrane proteins of the sarcolemma
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neuromuscular junction (NMJ)
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a synapse between a somatic neuron and a skeletal muscle fiber , muscle action potentials arise here
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Synapse
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a region where communication occurs between the neuron and another cell
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Synaptic Cleft
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a small gap that seperates the two cells
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Synapses
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seperates cells from direct physical contact
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Neurotransmitters
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allow the signal to be transmitted across the gap
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Acetylcholine (ACh)
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nuerotransmitter at a NMJ
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Sliding Filament Mechanism
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during muscle contraction myosin heads pull on thin filaments causing them to slide inward toward the M line; z discs come toward each other and the sarcomere shortens, but the thick and thin filaments do not change in length. The sliding of filaments and shortenign of sarcomeres causes the shorotenign fo the whole muscle fibeer and ultimately the entire muscle.
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Contraction Cycle ( how it works)
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at the beggining of contraction the sarcoplasmic reticulum relases calcium ions which bind to troponin and cause the troponin-tropomyosin complex to uncover the myosin-binding sites on actin, whent the binding sites ar free conrcation begins
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Contaction cyle (definiton)
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a repeating sequence of events that cause the filaments to slide. It consits of ATP splitting, myosin attachment of myosin to actin, the power stroke, and teh detachment of myosin from actin
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Relaxation
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2 changes permit the muscle fiber to relax
a. when nerve impulses from the neuron stop, ACh is no longer released into synaptic cleft, this prevents the genneration of a muscle action potential which prevents the relaese of calciium form the sarcomplasmic reticulum. b. the sarcoplasmic reticulum contains calcium active transport pumps that lowed the concentration of calcium in the sytosol this leads to release of calcium from toponin and moevement of topomyosin to block the myosin binding sites on actin |
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What is muscle tenison controlled by?
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stimulation frequency and motor unit recruitment
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When considering the contraction of a whole muscle , what does the tension generate depend on ?
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the number of fibers that are contracting in unison
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Motor Units
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a motor neuron and the muscle fibers it stimulates from, a single motor unit may innervate an average of 150 fibers.
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Twitch Contraction
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a brief contraction of all muscle fibers in a motor unit in response to a single action potential
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myogram
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a record of a muscle contraction includes three perios latent, contraciton, and relaxation
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Wave Summation
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the increased strength of a contraction resulting from the application of a second stimulus before the muscle has completely relaxed after a previous stiumlus
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Unfused Tetanus
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a sustained muscle contraction that permits partial relaxation between stimuli
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Fused Tetanus
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a sustained contraction that lacks even partial relaxation between stimuli
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Motor Unit Recruitment
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process of increasingthe number of active motor units, prevents fatigue and helps provide smooth muscular contraction rather than a series of jerky movements
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Muscle Tone
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a sustained partial contraction of portions of a relaxed skeletal muscle results in a firmness
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Isotonic Contraction
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when a constant load is moved through the range of motions possible at a joint include eccentric and concentric
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Isometric contraction
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the muscle does not shorten but tension increases no movement
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Eccentric
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in an isotonic contraction pickig up a book
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Concentric
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in an isotonic contraciton lowering a book
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what do muscle fibers create atp from
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creatine phospate
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how do muscle fibers create ATP
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anaerobic and aerobic cellular respiration
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How mnay sources for ATP production are there?
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three
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How long and what for is creatine phospate used for ?
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15 seconds and for maximal short burts of energy
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anaerobic cellular respiration
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partial catabolism of glucose to generate ATP and provide enough energy fro about 30-40 seconds of maximal muscle activity
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aerobic cellular respiration
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this is uesd for muscular activity lasting longer than 30 seconds , requirs oxygen , involves complete oxidation of glucose via cellular respiration
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What are the two sources of oxygen for muscle tissue ?
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diffusion from blood and release by myoglobin inside muscle fibers
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aerobic system
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will provide ATP for prolonged activty so long as sufficient oxygen and nutrients are available
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Muscle Fatigue
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the inability of a muscle to maintain its strngth of contration or tension , occurs when a mucls cannot produce enough ATP to meet its needs
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Recovery Oxygen Uptake
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elevated oxygen use after exercise
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myoglobin
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an oxygen reddish pigment
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Red muscle fibers
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have high myoglobin content
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White muscle fibers
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is low myoglobin content
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Slow oxidative Fibers
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smallest in diameter and therefore least powerful, large amounts of myoglobin and many blood capillaries generate ATP by aerobic cell respiration
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Fast Oxidative-Glycolytic Fibers
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are intermediate in diameter between the other two types, large amounts of myoglobin and many blood capillaries generate ATP by aerobic cellular respiration
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Fast Glycolitic Fibers
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are the largest in diameter and contain the most myofibrils, low myoglobin, and few blood capillaries , but contain large amounts of glycogen and generate ATP by glycolysis
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What are skeletal muscle fibers classifed as ?
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slow oxidative . fast oxidative-glycollytic, fast glycolytic
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Where is cardiac muscle tissue found ?
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Heart
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Where is smooth muscle tissue found ?
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in the hollow internal structures
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When do muscle fibers contract?
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when stimulated by their own autorhythmic fibers
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Major physiological difference between cardiac and skeletal muscle tissue ?
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autorhythmic continous fibers
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Visceral (single unit) smooth muscle
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found in the walls of hollow viscera and small blood vessels; the fibers are arranged in a network
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Multiunit smooth muscle
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found in large blood vessels, large airways, arrector pili muscles, and the iris of the eye. the fibers operate singly rather tha as a unit
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