BIOL 404-Exam 4-Muscle 11

  1. What ion controls cross bridge cycling in smooth muscle?
  2. How does Calcium regulate cross-bridge cycling in smooth muscle?
    • Ca regulates phosphorylation of myosin
    • Only phosphorylated myosin can bind actin
  3. What ion is important for myosin to bind actin in smooth muscle?
    Ca must enable Phosphorylation of Myosin
  4. What is the enzyme that phosphorylates myosin in Smooth muscle?
    Myosin light chain kinase (MLCK)
  5. What does Myosin light chain kinase do?
    Phosphorylates Myosin in smooth muscle
  6. What is an essential component for myosin light chain kinase to phosphorylate Myosin?
    Ca bound to Calmodulin
  7. What must occur for a smooth muscle cell to relax?
    Dephosphorylation of Myosin
  8. What enzyme dephosphorylates Myosin in smooth muscle?
    Myosin light-chain phosphatase
  9. What is the action of myosin light chain phosphatase?
    Dephosphorylation of Myosin in smooth muscle
  10. Where is Ca used during smooth muscle contraction found during relaxation?
    • SR
    • Extracellular fluid
  11. Are smooth muscle cells excitatory or inhibitory?
    Can be either
  12. What is the threshold value for smooth muscle response?
    None, is graded
  13. What is the role of Calmodulin?
    Binds Ca and complexes with myosin Light chain kinase and ATP to phosphorylate the Myosin chain
  14. At what point is ATP used in smooth muscle contraction?
    Hydrolyzed to ADP during the myosin phophorylation process
  15. Is Calmodulin found in smooth muscle cells?
  16. in Calmodulin found in Skeletal muscle cells?
  17. What part of the Nervous system controls Smooth muscle?
  18. What is the axonal component in smooth muscle that contains the neurotransmitter prior to release called?
  19. What is a varicosity?
    A swollen region of axon innervating smooth muscle that contains many neurotransmitter vesicles
  20. Where are neurotransmitters located within smooth muscle neuromuscular junctions?
    In the Varicosity of the axon
  21. What activates the release of neurotransmitter in smooth muscles?
    Action potentials
  22. What division of the ANS innervates smooth muscle?
    Parasympathetic and Sympathetic
  23. How many muscles cells can a single axon innervate?
  24. How many nerve cells can innervate a single smooth muscle cell?
Card Set
BIOL 404-Exam 4-Muscle 11
BIOL 404-Exam 4-Muscle 11