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2013-06-07 02:25:54
36 principles life

ch 36 principles of life
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  1. Muscle originates from mesodermal cells called
  2. This divides and elongates to become actin and myosin
  3. These are organized into myofilaments
    Myoblasts=muscle cells = muscle fiber
  4. This kind of muscle is very large and nulticucleate
    Skeletal (striped aka striated)
  5. Muscle cells are composed of two proteins
    Actin and myosin
  6. Thin filaments of muscle are
  7. Thick filaments of muscle are
  8. How many myofibrils does each skeletal muscle FIBER contain
    Hundreds to thousands
  9. Myofibrils are made of smaller, repeating units called
  10. Smalles unit of muscle fiber
  11. Why do myofibril have that striated appearance?
    Combination of thin &thick filaments
  12. When skeletal muscle contracts, this happens:
    Hzone and I bands get smaller, zones overlap get larger, z moves closer, width of a band doesnÂ’t change. Cross bridges form
  13. When do skeletal muscles contract?
    When they receive a nerve impluse
  14. What happens when action potential arrives at neuromuscular jnct?
    Acetylcholine is released and it diffuses across to the synapse
  15. ______ at the motor end plate causes action potential that leads to contraction
  16. Cell membrane of muscle
  17. T-tubles cary action potential from ____ to _______ ________.
    Sarcolemma; sarcoplasmic reticulum
  18. Similar to cell endoplasmic reticulum; transports/releases CA when receives signal
    SR (sarcoplasmic reticulum)
  19. What has to happen in order for muscles to contract
    Cross bridges must form between actin and myosin
  20. Active sites are usually blocked by
  21. When ______ from the SR bind to receptors on the troponin molecules, it changes config of troponin, which in turne causes what
    Calcium ions, tropomyosin to move away from active sites.
  22. These muscles are small with a single centrally placed nuc
  23. This unites the individual cell with heart muscle
    Intercalated disks
  24. This is a functional syncytium
  25. These muscles don't ever fatigue
    Cardiac and smooth
  26. Heart beat is ____; generated by muscle itself
  27. This muscle has a single nuc around center of the cell
  28. This muscle has irregular arrangements of actin and myosin, resulting in no striations
    Smooth muscle
  29. Stretching can cause ______ in smooth muscles
    Depolarization and action potentials.
  30. All the muscle fibers conrolled by a single motor neuron
    Motor unit
  31. Tension depends on
    # of motor units involved, freq at which motor units fire
  32. Stimulation of a single muscle fiber cproduces a
    Contraction-relaxation response.. (twitch)
  33. A twich can last between
    7-100 ms
  34. A single contraction is a
  35. If the muscle is stimulated a second time after a twitch,
    The new contraction will produce higher tansion than the previous; this is known as a treppe
  36. Repeated contractions and no relaxation
  37. What causes rigor mortis
    Ca++ diffusing to sarcoplasm from extracellular fluid.
  38. How long until rigor mortis stops
    Until last enzymes break down proteins 15-24 hours later.
  39. Slow conracting, low force sustained contraction
    Muscle tone
  40. Slow twitch muscle is red because
    Of high myoglobin content
  41. Slow twitch meat is good for
  42. Slow twitch characteristics
    Resistant to fatigue; energy from oxidative metab; high mitochondrial content; lots of blood vessels; lots of myoglobin (oxygen)
  43. Fast twitch characteristics
    Rapid movement of brief duration; fatigue quic; energy from glycolysis; low mitochon content; high glycogen; litle or no myoglobin; fewer blood vessels
  44. 3 ways to generate ATP for contraction
    Immediate; glycolytic; oxidative
  45. ATP and creatine phosphate . Short term
  46. Metabolizes carbs to lactate and purivate. Less than minuts use
  47. Metabolizes carbs completely to H20 and co2. fully activate after one minute. Slower to activate and replenish
    Oxidative system
  48. Act to anchor segments against substrate
  49. Skull, vertebral column, sternum, ribs
    Axial skeleton
  50. Pectoral and pelvic girdles, bones of arms, legs, hands and feet
    Appendicular skeleton
  51. Rigid calcium phosphate crystals
  52. Bones are composed of
    Osteocytes and laacunae
  53. Extracellular matrix of bones mostly
    Calcium phosphate
  54. Ostoblasts build
    New bone
  55. Osteoclasts
    Break down old bone
  56. Whats good for bone health
    Ca, Vitamin D, calcitonin, parathyroid hormone
  57. Superficial skull bone, clavicle, scapula. Forms on top of collagen mat
    Membrane bone (dermal bone)
  58. Long bones; cartilage replacement bones
    Endochondral bone
  59. How do muscles attach
    Skeletal element or tendon
  60. Where they contact the bone, connective tissue extends to