Chapter 8 Muscle Tissue Flashcards Preview

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Flashcards in Chapter 8 Muscle Tissue Deck (18):

What are the 5 properties of muscles?

  • Excitability - respond to chemicals released from motor neurons
  • Conductivity - ability to propagate electrical signals over membrane
  • Contractility - ability to shorten and generate force
  • Extensibility - ability to be stretched without damaging the tissue
  • Elasticity - ability to return to original shape after being stretched



Which of the following characteristics do neurons and muscle cells share?

A.  Extensibility
B.  Excitability
C.  Contractility
D.  Elasticity

B. Excitability


What are the three types of muscles?

  • Skeletal -Voluntary, Striated, Multinucleate, Attached to bone, skin, or fascia

Cardiac - Involuntary, Striated, Mononucleate, Autorhythmic (can self regulate beat)

Smooth - Involuntary, Non-striated, Mononucleate, Hair follicles, walls of hollow organs

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Skeletal Muscle Terminology

What is a muscle?

A group of fasicles


Skeletal Muscle Terminology

What are fasicles?

A group of muscle of cells(fibers)


Skeletal Muscle Terminology

What are muscle cells?

Long bundles of protiens (myofibrils)


Skeletal Muscle Terminology

What are myrofibrils?

Organized into sacomeres (contractile unit of muscles)


What are sarcolemma and sarcoplasm?

Sarcolemma - muscle cell membrane

Sarcoplasm - cytoplasm of a muscle cell


What is inside the sarcoplasm?

Myofibrils - long bundles of proteins
Myoglobin  - stores oxygen for use
Glycogen - A polymer of sugar

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What are tube-like structures which penetrate the interior of the cell of the sarcolemma?

Transverse tubules (T-tubules) - filled with extracellular fluid


What is the Sarcoplasmic reticulum?

  • muscle cell ER
    • Terminal cisternae - sacs of the SR, closely associate with T-Tubules
    • Storage area for calcium ions IN the muscle cell.

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What are the three types of myofilaments(protiens) and what do they form?

  • Thick filaments  myosin protein
  • Thin filaments  actin protein
  • Elastic filaments  titin protein
  • Together they form the sarcomere or the contractile unit

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What are the functions/structures of the Thick filaments of myofilaments?

  • Many myosin protein
  • A single myosin is shaped like a golf club (head is mobile), two twist together to make dimer (dimer = two units)
  • A thick filament consists of hundreds of myosin dimers
  • Binds and hydrolyzes ATP


What are the functions/structures of the Thin filaments of myofilaments?

  • Two chains of actin proteins, tropomyosin and troponin
  • Each actin unit (red ball) has an active site that can bind to the head of a myosin protein
  • Tropomyosin (white stripe) blocks the active site of myosin in relaxed muscles
  • Troponin (yellow) binds tropomyosin.  In the presence of calcium, troponin moves tropomyosin off active sites of actin


Which of the following molecules is the largest?

A.  Myofilament
B.  Myofibril
C.  Myosin
D.  Troponin

B. Myofibril


What and where is the A band, I Band, Z disc and M line in the picture?

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  • A band = Thick filament
    • Dark in color
    • Partially overlaps with thin filaments
    • Lighter in color at H Band, which is thick filament only
  • I band = Thin filament only
    • Light in color

Z disc = edge of sarcomeres
M line = mid of sarcomere
Both contain accessory proteins for stabilization
Pattern of dark and light are the striations



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What is Sarcomere Contration

  • Sliding filament theory
  • During contraction, thin filaments are pulled along thick filaments toward M-line (middle) of the sarcomere
    • H band (zone) decreases in size
    • I band decreases in size
  • USES ATP!!
  • Contraction of all sarcomeres, in all myofibrils, in all cells causes the muscle to contract as a whole