cp 9

📘 Flip Flashcards — Chapter 9 Muscle Tissue

Flashcard 1

Front: What is excitability in muscle tissue?

Back: The ability of muscle cells to detect and respond to a stimulus by generating an electrical signal.

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Flashcard 2

Front: What is contractility?

Back: The ability of muscle fibers to shorten forcibly when stimulated.

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Flashcard 3

Front: What is extensibility?

Back: The ability of muscle tissue to stretch without being damaged.

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Flashcard 4

Front: What is elasticity?

Back: The ability of muscle fibers to return to their original length after stretching.

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Flashcard 5

Front: What is the sarcolemma?

Back: The plasma membrane of a muscle fiber.

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Flashcard 6

Front: What is the sarcoplasm?

Back: The cytoplasm of a muscle fiber; contains myoglobin and organelles.

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Flashcard 7

Front: What are myofibrils?

Back: Rod-like structures inside muscle fibers that contain sarcomeres; make up ~80% of cell volume.

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Flashcard 8

Front: What is a sarcomere?

Back: The smallest contractile unit of muscle; extends from Z-disc to Z-disc.

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Flashcard 9

Front: What protein makes up the thick filament?

Back: Myosin.

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Flashcard 10

Front: What protein makes up the thin filament?

Back: Actin (plus tropomyosin and troponin).

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Flashcard 11

Front: What does tropomyosin do?

Back: Blocks actin’s active sites when Ca²⁺ is low.

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Flashcard 12

Front: What does troponin do?

Back: Binds Ca²⁺ and moves tropomyosin off actin’s active sites.

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Flashcard 13

Front: What is the function of the sarcoplasmic reticulum?

Back: Stores and releases Ca²⁺ for contraction.

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Flashcard 14

Front: What are T-tubules?

Back: Invaginations of the sarcolemma that carry action potentials deep into the muscle fiber.

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Flashcard 15

Front: What is a triad?

Back: One T-tubule + two terminal cisternae of the SR.

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Flashcard 16

Front: What does the sliding filament theory state?

Back: Myosin pulls actin toward the M-line, shortening sarcomeres without shortening filaments.

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Flashcard 17

Front: What is a motor unit?

Back: A motor neuron and all the muscle fibers it innervates.

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Flashcard 18

Front: What is recruitment?

Back: Increasing the number of active motor units to increase force.

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Flashcard 19

Front: What is the neuromuscular junction?

Back: The synapse between a motor neuron and a muscle fiber; uses ACh.

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Flashcard 20

Front: What does acetylcholinesterase do?

Back: Breaks down ACh to stop muscle contraction.

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Flashcard 21

Front: What is an end plate potential?

Back: Local depolarization caused by Na⁺ entering through ACh receptor channels.

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Flashcard 22

Front: What is excitation–contraction coupling?

Back: The process linking an action potential to Ca²⁺ release and sarcomere shortening.

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Flashcard 23

Front: What is cross-bridge formation?

Back: Myosin head attaches to actin when Ca²⁺ exposes binding sites.

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Flashcard 24

Front: What is the power stroke?

Back: Myosin head pivots and pulls actin toward the M-line.

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Flashcard 25

Front: What causes cross-bridge detachment?

Back: ATP binding to myosin.

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Flashcard 26

Front: What “cocks” the myosin head?

Back: ATP hydrolysis.

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Flashcard 27

Front: What is the latent period?

Back: Time between AP arrival and contraction; E–C coupling occurs here.

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Flashcard 28

Front: What is the origin of a muscle?

Back: The immovable bone.

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Flashcard 29

Front: What is the insertion of a muscle?

Back: The movable bone.

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Flashcard 30

Front: What is the epimysium?

Back: Dense irregular connective tissue around the entire muscle.

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Flashcard 31

Front: What is the perimysium?

Back: Dense irregular connective tissue around fascicles.

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Flashcard 32

Front: What is the endomysium?

Back: Areolar connective tissue around each muscle fiber.