Muscle Tissue

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Muscle Tissue Basic Muscle Anatomy

• p. 178-184

NOTE Myo-, mys-, sarco- All refer to muscle!
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3 Muscle Tissue Types
Skeletal Smooth Cardiac
Location Attached to skeleton (or skin) Walls of hollow organs (except heart) Walls of the heart
Cell Type / Chars. Elongated, cylindrical, multinucleate, striated Elongated, spindle-shaped, uninucleate, not striated Shorter, branching, uninucleate, striated, intercalated discs
Regulation Voluntary nervous control Involuntary nervous endocrine control also chemicals stretch Involuntary (pacemaker) nervous endocrine control
Speed Slow to fast, fatigue easily Very slow, sustainable Slow but rhythmic
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Smooth Muscle

• Often arranged in two perpendicular layers

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Cardiac Muscle

• Important that all cells contract at once
• Bundles of cells arranged in spiral / figure-8
  patterns
• Branching cells
• Intercalated discs join cells

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Skeletal Muscle

• Makes up the muscular system
• Muscles exert tremendous force
• Wrapped in layers of dense connective tissue to
  hold them together

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Functions of the Muscular System

• Produces movement
• Maintains posture
• Stabilizes joints
• Generates heat
• Byproduct of using ATP (energy) for skeletal
  muscle contraction

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Skeletal Muscle Tissue

• Muscle cell muscle fiber
• Specialized to contract
• Cells are bundled together to form fascicles
• Connective tissue wrappings
• Endomysium
• Perimysium
• Epimysium
• Continuous with tendons and aponeuroses

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Tendons

• Structure
• Dense connective tissue (collagen fibers)
• Functions
• Attach muscles to bone, cartilage, or connective
  tissue coverings
• Conserve space across joints
• Durable enough to cross rough bony projections

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Aponeuroses
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• Myofibrils
• Myofilaments

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Sarcomere functional unit of muscle
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Myofilaments

• Actin (thin filaments)
• Myosin (thick filaments)
• Myosin heads
• Form cross-bridges
• with actin
• Z discs

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Striations

• Light (I) bands
• Dark (A) bands