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MUSCLE TISSUE

MUSCLE TISSUE. A few short facts: Movement of the body is important for survival. There are more than 600 muscles in the human body 40% - 50% of body weight Muscles pulling on bones is responsible for movement

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MUSCLE TISSUE

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  1. MUSCLE TISSUE

  2. A few short facts: • Movement of the body is important for survival. • There are more than 600 muscles in the human body • 40% - 50% of body weight • Muscles pulling on bones is responsible for movement • The way muscle is grouped and their relationship to joints determines the type of movement they create

  3. Connective tissue surrounding muscles tissue • Endomysium– around muscle cells or fibers • Perimysium - hold groups of muscle fibers together • Epimysium – covers the entire muscle group • All these layers attach the muscle to the bone so the muscle pulls as one unit

  4. Broad flat sheet of connective tissue that covers muscle groups called aponeurosis usually merges with fibrous wrappings of another muscle You will see that clearly on the cat

  5. Structure of skeletal muscle Size, shape and fiber arrangement The movement and strength of a muscle is determined by its overall shape and type of attachment

  6. Parallel • Vary in length but are strap-like • Fibers are running parallel to each other

  7. Convergent Wide point of attachment to a small point of attachment

  8. Pennate Feather-like

  9. Fusiform Close to parallel in the middle or belly of muscle but converge to tendon at both ends

  10. Spiral Fibers that twist Between their points of attachments

  11. Circular Called sphincters Circle around a body tube or opening

  12. Most muscles span at least one joint, some span two joints

  13. Names for the attachments of muscles Origin The point of attachment that does not move when the muscle contracts Insertion The point of attachment that moves when the muscle contracts

  14. Skeletal Muscles act in groups • Some contract while others relax

  15. Prime mover • Agonist • The muscle or group of muscles that directly performs a specific movement • Antagonists • Muscles that directly oppose the prime mover • The antagonists is relaxed when the prime mover is contracting • Provides precision and control during the contraction of the prime mover • the name antagonists is misleading

  16. Synergists • Muscles that contract at the same time as the prime mover • Complement the prime mover actions to make a more effective movement • Fixator • Joint stabilizers • Maintain posture or balance • Example would be the muscles in the front and back of the thigh stabilizing the leg when standing

  17. Most movements are very complex Most muscles function as prime mover, antagonists synergists or fixators at some time depending on the movement

  18. A prime mover in flexing arm at the elbow is……. The Antagonist is……. Is it different when the arm is above the head?

  19. Do you remember levers, which one is which? In the body: all movement is made by 3rd class levers. The muscle insertion is very close to the joint being moved. The movement is strong but it is also fast In the body: face is the load, the c2 vertebrae is the fulcrum, the muscles of the neck and upper back is the pull In the body: some anatomists do not agree. Some say raising up on one’s toes is a 2nd class lever. Fulcrum is the toes point of contact with the ground, load is the ankle, pull is the gastrocnemius muscle in the lower leg Opening mouth against resistance Figure 10-4C.Lever classes. A, Class I: fulcrum (F) between the load (L) and force or pull (P);B, Class II: load (L) between the fulcrum (F) and force or pull (P);C, Class III: force or pull (P) between the fulcrum (F) and the load (L). The lever rod is yellow in each.

  20. So……

  21. When a body part is moved the muscle moving that part usually does not lie over the part being moved. The muscle doing the moving is usually proximal to the part being m0ved Muscle doing the moving Body part being moved

  22. Before we go to the lab to look at the cats we need to understand how muscles are named. If we understand how they are named the language isn’t as foreign as it appears at first glance

  23. Location brachialis - arm, upper arm gluteus - buttock Function adductor – moving the leg toward the midline of the body abductor – moving the part away from the midline of the body

  24. Shape deltoid – triangular Direction of Fibers rectus – meaning straight Number of Heads or Divisions “cep” - means head triceps, quadriceps biceps bracahii

  25. Point of Attachment origin and/or insertion points Sternocleidomastoid Size of Muscle Size compared to size of nearby muscles gluteus maximus, gluteus medius, gluteus minimus

  26. When you and your lab partner start looking at the cat keep these things in mind • Use the larger muscles as a guide • Try to figure out to which bones the two ends attach • Determine what is being moved when the muscle shortens – what is being moved, what is staying stationary • insertion and origin

  27. Deltoid • Pectoralis major • Latissimusdorsi • Serratus anterior • Linea alba • Rectus abdominis • External oblique • Transverse abdominis • Internal oblique

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