The muscular system
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The muscular system






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The muscular system Presentation Transcript

  • 2. INTRODUCTION • The muscular system is composed of specialized cells called muscle fibers. • These fibers are different lengths and shapes and form to become muscles. • Muscles make up about 42% of a person’s total body weight. • Muscle fibers are held together by connective tissue , enclosed in “fascia”. • Muscles must have proper oxygen and nutrition to function properly.
  • 3. TYPES OF MUSCLE TISSUE Muscle Tissue Skeletal Voluntary Satiated cells Smooth Involuntary Blood vessels, Urinary bladder, Digestive system Cardiac Muscle Tissue Found in the Heart Striated and Involuntary
  • 4. TYPES OF MUSCLE TISSUES CONT… • Skeletal muscle • Smooth Muscle • Cardiac Muscle
  • 5. Skeletal Muscle • How many different muscles can there be? • ~660
  • 6. CHARACTERISTICS OF MUSCLES of muscles to • Contractility – the ability shorten • Elasticity – the ability of muscles to go back to its original shape • Excitability – the ability of muscles to respond to stimuli • Extensibility – the ability of muscle to lengthen • Sphincter – muscles that constrict openings
  • 7. CLASSIFICATION OF MUSCLES FUNCTIONALLY • Voluntary – can be moved at will STRUCTURALLY • Striated – have stripes across the fibers • Smooth – no striations • Involuntary – can’t be moved intentionally
  • 8. CATEGORIES OF SKELETAL MUSCLE ACTIONS ACTIONS CATEGORIES • Extensor • Flexor • Abductor • Adductor • Levator • Depressor • Rotator • Sphincter • • • Increases the angle at a joint • • • • • Moves limb toward midline of body Decreases the angle at a joint Moves limb away from midline of body Moves insertion upward Moves insertion downward Rotates a bone along its axis Constricts an opening
  • 9. NAMING SKELETAL MUSCLES Trapezius • Shape: • deltoid (triangle) Deltoid • trapezius (trapezoid, 2 parallel sides) • serratus (saw-toothed) • rhomboideus (rhomboid, 4 parallel sides) • orbicularis and sphincters (circular) Serratus anterior Rhomboideus major
  • 10. MUSCLES NAMED BY SIZE • Maximus (largest) • minims (smallest) • Longus (longest) • Brevis (short) • Major (large) • Minor (small) Psoas minor Psoas major
  • 11. MUSCLES NAMED FOR NUMBER OF ORIGINS • Biceps (2) Biceps brachii • Triceps (3) • Quadriceps (4)
  • 12. MUSCLES NAMED FOR ACTION • Flexor carpi radialis (extensor carpi radialis) – flexes wrist • Abductor pollicis brevis (adductor pollicis) – flexes thumb • Abductor magnus – abducts thigh • Extensor digitorum – extends fingers Adductor magnus
  • 13. COVERINGS OF SKELETAL MUSCLE • Epimysium • Connective tissue that covers the entire muscle • Lies deep to fascia • Perimysium • Surrounds organized bundles of muscle fibers, called fascicles • Endomysium • Connective tissue that covers individual muscle fibers (cells)
  • 14. SARCOMERE Now let us take a look at Sarcomere: • A sarcomere is the functional unit of skeletal muscle • A sarcomere is the area between adjacent Z-lines. • During a muscle contraction the z-lines move together and the sarcomere shortens.
  • 15. Picture of a Sarcomere
  • 16. Type I slow fibers of skeletal muscle Type II fast fibers of skeletal muscle Slow tonic specially designed for postural muscles, red in colour due to high concentration of myoglobin and rich in mitochondria and oxidative enzymes Fast tonic Varient of Type II contractions needed for body movement, pale colour rich in glycogen and phosphorylases Highly resistance to fatigue due to well-developed in aerobic respiration Easily fatigue Intermedia te fibers of skeletal muscle Resistant to fatigue The types of Fibers
  • 17. THERE ARE ABOUT 60 MUSCLES IN THE FACE. Smiling is easier than frowning. It takes 20 muscles to smile and over 40 to frown. Smile and make someone happy.
  • 18. MACROSTRUCTURE Skeletal muscle c.s. 40x It is the number of muscle fibers packed into a given muscle cross-sectional area that determine overall force-generating capacity
  • 19. MICROSTRUCTURE • basic functional unit of muscle • Striated (light & dark bands) • Contains ACTIN & MYOSIN filaments that are responsible for contraction
  • 20. REFERENCES Dimapilis, H. 2014. Muscular System. 05/03/2014 Accessed Agamez, M. 2011. An overview comparing the three different types of muscular tissue. Accessed on the 05/03/2014 Marydelaney, L. 2009, Muscular System. Accessed 05/03/2014 By Itsebo, 2011. The muscular-system. Accessed 05/03/2014 • Cerny, L. 2009. Applied Excecise Physiology, Muscular Skeletal. Accessed 05/03/2014