Anatomy of Skeletal Muscle

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Anatomy of Skeletal Muscle

• By ziminiqueina yoflemsteinowe
• Mrs. A 2004

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Role of the Muscle Tissue

• Movement
• Posture/Position
• Support soft tissues
• Guard
• Maintain temperature

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Get your Connective Tissue Groove On!

• Epimysium- dense CT collagen fibers around muscle
  (outside, part of deep fascia)
• Like in the bone?
• Perimysium-around muscle fascicle (middle bundle
  of fibers) blood vessles
• Endomysium- delicate loose CT, surrounds muscle
  fibers (inner) cappilaries satellite cell
  imbedded

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Blood Vessels and Nerves

• In the epimysium, perimysium, endomysium
• Contraction of skeletal muscles is due to
  stimulation from the central nervous system.
• Tendons Aponeurosis connect muscle to bone
  (extension of epimysium)
• Fascia-fibrous connective tissue separates
  muscles.

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Muscle Cells Hierarchy

• Myoblast- embryonic cell
• Muscle Fibers multinucleated
• Satellite Cells give rise to myoblasts for
  repair
• Sk. Muscle-gt fasciculi-gt fibers -gt myofibrils

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Microanatomy of Skeletal Muscle Fibers with
Myofibrils

• The sarcolemma (plasma membrane) inside
  endomysium and transverse T tubules
• Myofibrils- myofilaments of actin and myosin
• Sarcoplasm- liquid around myofibrils
• Sarcoplasmic Reticulum (smooth ER) transport
  surround myofibrils
• Sacromeres on the myofibril

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Muscle Organelles

• Cytoskeleton
• Mitochondria
• sER
• cisternae
• Membrane
• Cytoplasm
• Cilia/Microvilli
• Nucleus

• Myofibrils
• Mitochondria
• SR-
• terminal cisternae
• Sarcolemma
• Sarcoplasm
• Transverse Tubules
• Multiple-Nuclei

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Sacromeres

• Sacromere Organization
• Thin Filaments (actin)
• Thick Filaments (myosin)

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Sacromere Organization in Myofibril

• Thin Filaments (actin)
• Thick Filaments (myosin)
• I Band (thin actin only)
• Z Lines divides sarcomeres
• A Band (constant size)
• M Line middle
• H Zone (kind of like danger zone!)
• Zone of Overlap (triad) changes with contraction

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Thin Filaments

• F actin (300 G actin) .beads
• Active Sites/G actin
• Tropomyosinropes
• Troponin3 knots

Ca
Ca
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Thick Filaments

• Tails-- attached to M line (H zone)
• Heads and hinge arranged in spiral
• Cross-bridges
• SLIDING FILAMENT THEORY
• Thin filaments are sliding toward the center of
  the sarcomere, along side the think filaments. H
  band I zone decrease, zone overlap increases, Z
  lines move toward each other during a
  contraction.

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The Sliding Filament Theory

• Get ready to get your GROOVE on!!!! Cause its
  time for class participation and
  ourINTERPERATIVE DANCE!

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The End-ish