anatomy inal- ch. 6

  1. myofibril
    • bundles of myofilaments
    • contractible unit of muscle fiber
    • thick and thin overlap in pattern to create striations
    • I and A band (H zone, M line)
  2. sliding filament theory
    when myosin binds it springs toward center of sarcomere; pulls actin myofilaments (contraction) ATP causes myosin to relase and Ca is reabsorbed into SR and binding sites are closed
  3. direct phosphorylation
    • only muscle cells contain creatine phosphate (high energy)
    • after atp is depleted, adp is left
    • cp transfers energy to adp to regenerate atp
    • cp supplies are used in 20 seconds
  4. aerobic respiration
    • metabolic pathwaays that occur in mitochondria
    • slower reaction
    • requires continuous oxygen
    • glucose is broken down to CO2 and water; releases energy
    • oxygen binds with protein myoglobin
    • produces 36 atp
  5. anaerobic glycolysis and lactic acid formation
    • reaction that breaks down glucose without oxygen
    • glucose is broken down to pyruvic acid
    • pyruvid acid to lactic acid
    • not as efficient, but fast
    • huge amounts of glucose needed
    • lactic acid produces muscle fatigue
  6. isotonic contractions
    • myofilaments able to slide past eachother during contractions
    • endurance exercise (biking)
    • stronger, flexible muscles
    • resistance to fatigue
    • increase in blood supply to muscles
    • muscle shortens
  7. isometric contractions
    • tension in muscles increases; length doesn't change
    • increase in muscle size
    • resistance exercises (lifting)
  8. muscle tone
    • some fibers are contracted even in relaxed muscle
    • involuntary continued¬†contraction
    • diff. fibers contract at diff times
    • helps maintain posture
    • declines during sleep
  9. agonist
    prime mover; muscle that's contracting
  10. antagonist
    muscle that is relaxing or stretching; example biceps and triceps are opposing muscles
  11. synergist
    "assists" an agonist by stabilizing the joint; prevent unwanted action of another muscle
  12. fixator
    synergist that stabilizes the origin of the prime mover
  13. direction of fibers (3)
    • oblique= diagonal to midline
    • rectus= parallel to midline
    • transverse= perpendicular to midline
  14. size (6)
    • brevis- short
    • latissimus- widest
    • longus- longest
    • major- large, maximus- larger, magnus-largest
    • vastus-great
    • minor-smaller, minimus- smallest
  15. number of tendons of origin (3)
    • biceps- 2 originis
    • triceps- 3 origins
    • quadriceps- 4 origins
  16. shape (8)
    • deltoid- triangular
    • gracilis- slender
    • orbicularis- circular
    • platys- flat
    • quadratus- square
    • rhomboideus- rhomboid or diamond
    • serratus- saw toothed
    • trapezius- trapezoidal
  17. location near another structure
    • ex. frontalis is located near frontal bone
    • tibialis is located near tibia
  18. depressor
    downward movement
  19. levator
    upward movement
  20. extensor
    increase joint angle
  21. flexor
    decrease joint angle
  22. sphincter
    decrease size of an opening
  23. tensor
    increases rigidity
  24. flexion
    • movement in the sagittal plane
    • -brings body part forward
    • hinge joints
    • -ex. knee or elbow
    • ball and socket joints
    • -ex. bending forward at hip
  25. extension
    • opposite of flexion
    • increases the angle of 2 bones
    • -brings body part to rear
    • -ex. straightening leg or arm
    • if extension is greater than 180 degree=hyperextension
  26. rotation
    • circular movement of bone around its axis
    • movement between first 2 cervical vertebra
    • ex. head rotation, "no"
  27. abduction
    • moving a limb away from the midline
    • frontal plane
    • raising arm laterally
  28. adduction
    • opposite of abduction
    • movement of a limb towards the midline
    • frontal plane
  29. circumduction
    • combination of flexion, extension, abduction, and adduction
    • proxiaml end of limb is stationary, distal end moves in circle
    • circular or cone shaped movement
    • ball and socket joints of shoulder- rotating hand from wrist
  30. dorsiflexion
    lifting the foot so the superior surace nears the shin (standing on your heels)
  31. plantar flexion
    depression the foot (pointing toes)
  32. inversion
    turn the sole of the foot medially (towards the middle)
  33. eversion
    turn the sole laterally (towards outside)
  34. supination
    • forearm rotates laterally
    • palm faces anteriorly
    • radius and ulna are parallel
  35. pronation
    • forearm rotates medially
    • palm faces posteriorly
    • bones form an x
  36. opposition
    movement of thumb to the tip of other fingers
  37. depression
    to move down
  38. elevation
    • to move up or lift body
    • shrugging shoulders
  39. gliding
    • slipping past, slight displacement of bones
    • flat bone moves over flat bone
    • carpals of wrist
  40. protraction
    slide lower jaw forward
  41. retraction
    slide jaw back
  42. fascicle
    bundle of muscle fibers within a muscle
  43. fusiform
    • type of fascicle
    • large belly, fewer fibers at ends near tendons
    • example: biceps brachii
  44. convergent (usually triangular)
    • type of fascicle
    • fascicles spread (fan) out at one end and converge at other end
    • origin of the muscle is broad
    • fascicles converge toward the tendon of insertion
    • example: pectoralis major
  45. pennate
    • type of fasciclce
    • tendon extends through most of muscle length, short fibers
    • greater power but a shorter range of motion
    • 3 types- unipennate, bipennate, multipennate
  46. unipennate
    • fascicles insert into one side of the tendon
    • example: extensor digitorum muscle, forearm muscle that extends the finger joints
  47. bipennate
    • fascicles insert into the tendon from both sides
    • example: rectus femoris muscle, extends the knee
  48. multipennate
    • several tendons, each with bipennate fascicles
    • example: deltoid muscle of the shoulder
  49. parallel
    • type of fascicle
    • fascicles are parallel to long axis of muscle
    • fibers contract and shorten, diameter increases
    • strap-like, end in flat tendons
    • greater range of motion with less power compared to pennate muscles
    • example: sartorius muscle of the thigh
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anatomy inal- ch. 6