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MUSCLES

MUSCLES. http://www.gwc.maricopa.edu/class/bio201/muscle/mustut.htm http://www.meddean.luc.edu/lumen/meded/GrossAnatomy/dissector/mml/index.htm. THREE TYPES OF MUSCLES. Cardiac Smooth Skeletal. PROPERTIES OF MUSCLES. Ability to contract Extensibility – ability to be stretched

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MUSCLES

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  1. MUSCLES

  2. http://www.gwc.maricopa.edu/class/bio201/muscle/mustut.htm • http://www.meddean.luc.edu/lumen/meded/GrossAnatomy/dissector/mml/index.htm

  3. THREE TYPES OF MUSCLES • Cardiac • Smooth • Skeletal

  4. PROPERTIES OF MUSCLES • Ability to contract • Extensibility – ability to be stretched • Elasticity – ability to return it its original length • Irritability – ability to receive and repord to stimuli

  5. TERMS • Myo – muscle • Sacro - flesh • Muscle fiber – individual muscle cell

  6. SKELETAL MUSCLE • Bundles of muscle fibers that are package to form the organ

  7. CONNECTIVE TISSUE OF SKELETAL MUSCLE • Warps or bundles up muscle fibers • Provides support and strength to muscle • Keeps muscles form being ripped apart under tremendous forces

  8. PARTS OF MUSCLE FIBER • Endomysium – connective tissue sheath that wraps each individual muscle fiber • Perimysium – coarser fibrous membrane that surrounds several muscle fibers • Fascicle – bundle of fibers • Epimysium – tougher layer of connective tissue that covers many fascicles – covers entire muscle –

  9. Epimysium

  10. EPIMYSIUM • Ends of it will blend into • Tendons • Aponeurosis – attaches muscles indirectly to bones, cartilage or connective tissue

  11. TERMS Origin – muscle attaches to stationary bone Insertion – muscle attaches to bone that moves When muscle contracts, one bone moves and the other is stationary

  12. MOVEMENT OF BODY PARTS • Body part is moved by a group of muscles: • Prime mover • Synergists • fixators • Antagonists - pairs that work opposite

  13. Tendon- connective tissue that attaches muscle to bone • Very tough – thus is gives muscles durability • Does not wear out next to rough projections of bone • Usually tendon that passes over bony joint and not muscle

  14. Muscles are arrange differently depending on where they are located

  15. FUNCTIONS OF MUSCLES • PRODUCE MOVEMENT • MAINTAIN POSTURE • STABALIZE JOINTS • GENERATE BODY HEAT

  16. COMPONENTS OF SKELETAL MUSCLE • Saroclemma • Sarcoplasmic reticulum • Sarcoplasm • sarcomere

  17. Parts of Sarcomere • Myofibril (fibril) 0 complex organelle composed of bundles of myofilaments. Fill the cytoplasm of muscles. • Myofilaments – threadlike filaments – has alternating light and dark bonds - composed of 2 key proteins • Actin • myosin

  18. PROTEINS OF MYOFILAMENTS

  19. myosin • Thick protein filament • Contains ATPase – splits ATP to generate the energy needed for muscle contraction • Extends the entire length of the dark A boand • Midpart is smooth • End are studded with projections called myosin heads or cross bridges

  20. actin • Thin filament • Made up of contractile protein • Actin is anchored to the Z line • I band – 2 adjacent sarcomeres and contains only actin • Actin does not extend into the middle of the A band which makes the H zone appear lighter

  21. When contraction occurs – actin filament slide toward each other into the center of the sarcomeres • Light zone disappears because actin and myosin totally overlap

  22. SLIDING FILAMENT THEORY

  23. Relaxed muscle has regulatory proteins on the actin to prevent myosin from bending

  24. AP stimulates the sarcolemma of the muscle • Ca ions are released from the sarcoplasmic reticulum • Ca ions bind to the regulatory proteins on the actin • This changes the shape and location of the regulatory proteins on the actin

  25. Binding sites on the actin become exposes • Myosin heads attach to the binding sites on the actin (called cross bridge formation) • When heads attach, they snap toward center of sarcomere (power stroke) • This pulls actin toward center of sarcomere • ATP provides Energy to release and recock myosin heads

  26. Cross bridge is broken • Myosin head reattaches to another site further along the actin (another cross bridge and power stroke) • This is called walking of the myosin • AP ends • Ca ions reabsorbed by sarcoplasmic reticulum

  27. Regulatory proteins return to their original shape and position • Myosin can’t attach • Muscle relaxes

  28. MACROSCOPIC CONTRACTION • Muscle cell - all or none response • Thousands of muscle cells form the organ • Skeletal muscle’s response is graded – different degrees of contraction

  29. 2 WAYS TO PRODUCE GRADED REPONSE • 1 - Changing the speed of muscle stimulation • 2 - Changing the number of muscle cells stimulated

  30. Pat vs. slap • If few cells (motor units) are stimulated, then the contraction of the muscle is slight. • As more cells are stimulated, the grater the contraction

  31. THE 5 GOLDEN RULES OF SKELETAL MUSCLE ACTIVITY

  32. All muscles cross at least 1 joint • The bulk of the muscle lies proximal to the joint crossed. • All muscles have at least 2 attachments • Muscles can only pull, they never push • During contraction muscle moves toward the origion

  33. DISEASES • Tetanus • Muscular dystrophy • Duchenne muscular dystrophy • Problems associated with steroid use. • What is the proper way to lift a heavy object?

  34. Muscle twitch • Bell’s palsy • Inguinal hernia • Muscle cramp

  35. Pictures to label

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