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80 Cards in this Set
- Front
- Back
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What is released from the sarcoplasmic reticulum after an action potential reaches a muscle cell?
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Ca2+
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What does calcium bind to in a muscle cell?
Where on the cell? |
Troponin C
Thin Fliaments |
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What affect does calcium binding to troponin have on the muscle cell?
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Conformational change causing tropomyosin to move and allow Actin to bind w/ myosin
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_____ myosin binds weakly to _____ subunits; however, when inorganic _____ is released from myosin, they then bind tightly to the _____ subunits.
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High-energy
Actin Phosphate Actin |
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The repeated pulling of the _____filaments past the _____ filaments towards the centers of the sarcomeres draws the Z lines closer together, and the muscle fibers shorten. What is this known as?
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Sliding Filament theory
Thin Thick |
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What is the major determinant for a sustained muscle contraction?
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The presence of Ca2+
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In the contractile cycle what dissociates the actomyosin complex?
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ATP replacing ADP on Myosin heads
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What is the composition of thick filaments?
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Myosin
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What is the composition of thin filaments?
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Actin
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What is not considered a source of replenishment for ATP in the muscles?
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Lactic Acid
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What provides the immediate source of energy for muscle contraction?
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Hydrolysis of ATP
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What are the three sources of ATP replenishment for the muscles?
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Creatine Phosphate
Glycogen Cellular repiration |
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How is Creatine phosphate used as a reservoir for ATP?
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Donates high energy phosphate
Creatine phosphate + ADP <-> creatine +ATP Creatine Phosphate 10x > ATP in muscle fiber |
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How much glycogen is contained in a muscle fiber?
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1% glycogen
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How does muscle fiber use glycogen as an energy store?
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Glycogen degraded by glycogenolysis
Produces glucose-1-phosphate Goes through glycolytic pathway to form 2 ATP |
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Is glycogen stores sufficient for the muscles needs?
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No, only temporary eventually needs cellular respiration
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Required to meet the ATP needs of a muscle engaged in prolonged activity and is also required afterwards to enable the body to resynthesize glycogen from lactic acid produced earlier.
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Cellular Respiration
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During exercise what is thought to be an immediate source for high-energy phosphate groups with which to replenish ATP?
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Creatine Phosphate
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What are the phosphate compounds that have a higher phosphate group-transfer potential than ATP?
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Phosphoenolpyruvate
Carbomoyl phosphate Acetyl phosphate Creatine phosphate 1,3-diphosphoglyceric acid |
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What are the phosphate compounds that have a higher phosphate group-transfer potential than ATP?
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Glucose-1-phosphate
Glucose-6-phosphate Fructose-1,6-diphosphate Creatine |
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What is the motor unit of a muscle fiber?
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Alpha-motor neuron + muscle fibers that it innervates
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Motor units are recruited in order of size of the motor unit. If only a small amount of force is required only small units are recruited. Larger force requires more and larger motor units.
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Size Principle
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What causes the cessation of motor unit recruitment in the jaw muscles when closing?
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Periodontal mechanoreceptors
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This means it is not necessary to activate all of the motor units in a muscle.
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Fractionation
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What is the contraction of a skeletal muscle controlled by?
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Nervous system
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What causes the depolarization of muscle fibers?
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Action potentials traveling down somatic alpha-motor neuron
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What is the junction between the terminal of a motor neuron and a muscle fiber?
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Neuromuscular junction
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What happens when an action potential reaches the neuromuscular junction?
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Calium enters neuron causing acetylcholine release through synaptic vesicles
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What does acetylcholine bind to on the membrane of the muscle fiber?
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Nicotinic receptors
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What does the depolarization of the muscle fiber membrane lead to?
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Action potential
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What are the characteristics of fast and slow twitch muscle fibers with respect to Myosin-ATPase activity?
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Slow Twitch Type1: Low
Fast Twitch Type 2: High |
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What are the characteristics of fast and slow twitch muscle fibers with respect to speed/intensity of contraction?
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Slow Twitch Type1: Slow/low
Fast Twitch Type 2: Fast/high |
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What are the characteristics of fast and slow twitch muscle fibers with respect to Resistance to fatigue?
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Slow Twitch Type1: High
Fast Twitch Type 2: Low |
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What are the characteristics of fast and slow twitch muscle fibers with respect to Oxidative capacity?
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Slow Twitch Type1: High
Fast Twitch Type 2: Low |
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What are the characteristics of fast and slow twitch muscle fibers with respect to Enzymes for anaerobic glycolysis?
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Slow Twitch Type1: Low
Fast Twitch Type 2: high |
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What are the characteristics of fast and slow twitch muscle fibers with respect to mitochondria?
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Slow Twitch Type1: Many
Fast Twitch Type 2: Few |
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What are the characteristics of fast and slow twitch muscle fibers with respect to sarcoplasmic reticulum?
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Slow Twitch Type1: Less extensive
Fast Twitch Type 2: More extensive |
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What are the characteristics of fast and slow twitch muscle fibers with respect to capillaries?
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Slow Twitch Type1: Many
Fast Twitch Type 2: Few |
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What are the characteristics of fast and slow twitch muscle fibers with respect to Myoglobin content?
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Slow Twitch Type1: High
Fast Twitch Type 2: Low |
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What are the characteristics of fast and slow twitch muscle fibers with respect to Glycogen content?
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Slow Twitch Type1: Low
Fast Twitch Type 2: High |
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What is oxidative capacity related too?
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1. # of capillaries
2. Myoglobin content 3. # of mitochondria |
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The finer the movement required the _____ the number of muscle spindles in a muscle.
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Greater
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What are the two sensory organs that fine tune muscle tone?
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Muscle Spindle (measures muscle length)
Golgi Tendon Organ (measures muscle tension) |
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What are the three components of the muscle spindle?
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Specialized muscle fibers
Sensory terminals Motor terminals |
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What are also known as intrafusal fibers?
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Specialized sensory fibers
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What are the sensory terminals inn a muscle spindle?
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Group Ia and II efferents
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What is the motor terminal for a muscle spindle?
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Gamma motor neuron (efferent)
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What does the muscle spindle activate when stretched?
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Alpha-motor neuron
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What is the golgi tendon organ innervated by?
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Single-group Ib sensory (afferent) fiber
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What does the Golgi tendon organ do to a muscle fiber?
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Inhibits it
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Small, highly differentiated part of the muscle tissue located within the belly of muscles and runs parallel with the main muscle fibers.
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Muscle Spindle
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What are wrapped around specialized muscle fibers that belong to the muscle spindle (_____ _____) and are quite separate from the fibers that make up the bulk of the muscle (_____ _____)
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Annulospiral endings (sensory terminals)
Intrafusal fibers Extrafusal fibers |
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When a muscle is _____, the _____ reflex reacts. This reflex is considered _____, and the result is _____.
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Stretched
stretch monosynaptic relaxation |
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What is another name for the stretch reflex?
What kind of stretching of the muscles does it respond to? |
Myotatic reflex
Passive |
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The muscle stretch is detected by _____ _____ whose afferents (_____ _____) synapse with _____ _____ neurons (alpha motor neurons) and _____ (1a inhibitory neurons)
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muscle spindles
1a fibers lower motor neurons Interneurons |
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What is the stretch reflex important for maintaining?
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Posture and muscle tone
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What is the basic function of the muscle spindle?
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Send info to CNS concerning length and tension
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What are the sensory receptors that serve the stretch reflex/
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Proprioceptors
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What is the number of synapses, stimulus, afferent fibers, and response to the Stretch reflex (knee jerk)?
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# of synapses - Monosynaptic
Stimulus - Muscle stretched Afferent fibers - Ia Response - Muscle contraction |
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What is the number of synapses, stimulus, afferent fibers, and response to the Golgi tendon reflex (clasp knife)?
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# of synapses - Disynaptic
Stimulus - Muscles contract Afferent fibers - Ib Response - Relaxation of the muscle |
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What is the number of synapses, stimulus, afferent fibers, and response to the flexor-withdrawal reflex (after touching a hot stove)?
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# of synapses - Polysynaptic
stimulus - Pain Afferent fibers - II, III, IV Response - Ipsilateral flexion, contralateral extension |
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What is the reverse of the stretch reflex?
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Golgi tendon reflex
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A poly-synaptic reflex that is used when a person touches a hot object or steps on a needle.
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Flexoe-withdrawal reflex
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How many basic elements are there in all reflex arcs?
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6
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An organ of response (ie. skeletal muscle)
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Effector
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Why are reflexes relatively quick?
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They involve few neurons
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Reflexes are either ______ (contraction of skeletal muscle) or _____ (activation of smooth and cardiac muscle)
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Somatic
Autonomic |
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What are the six basic elements of a reflex arc?
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1. receptor
2. sensory (afferent) neuron 3. Integration center (CNS) 4. Interneuron 5. Motor (efferent) neuron 6. effector |
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somatic reflexes mediated by the spinal cord
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Spinal reflexes
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The process where when a stretch reflex stimulates the stretched muscle to contract, antagonistic muscles that oppose the contraction are inhibited.
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Reciprocal Inhibition
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What are the fibers that make up the bulk of the muscle?
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Extrafusal fibers
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What are the fibers of the muscle that are innervated by alpha-motor neurons?
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Extrafusal fibers
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What type of muscle fibers provide the force of a muscle contraction?
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Extrafusal fibers
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What type muscle fiber is encapsulated in sheaths to form muscle spindles?
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Intrafusal fibers
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What type of muscle fiber is innervated by gamma-motor neurons (efferent neurons)
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Intrafusal fibers
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What are the two types of sub-groups of Intrafusal fibers?
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Nuclear bag fibers
Nuclear chain fibers |
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What type of muscle fibers detect fast, dynamic changes in muscle length and tension?
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Nuclear bag fibers (intrafusal)
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What type of muscle fibers are innervated by group 1a afferents - fastest in the body?
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Nuclear bag fibers (intrafusal)
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What type of muscle fibers detect static changes in muscle length and tension?
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Nuclear chain fibers (intrafusal)
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What type of muscle fibers are innervated by the slower group II afferents?
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Nuclear chain fibers (intrafusal)
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