Cardio - Lec 13: Vascular Smooth Muscle Function

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Across
  1. 3. in beta receptors  NA binds  activates adenylate __________  increases cAMP production  relaxation  vasodilation.
  2. 5. nitric oxide is released by endothelial cells that are being affected by high velocity blood flow (sheer stress)  acts on underlying smooth m cells to INCREASE levels of ______  vascular relaxation. (cAMP also has same effect)
  3. 6. ___________ hyperaemia is a term given to the temporary increase n blood flow after a period of reduced blood flow (due to the same build up of metabolic products as in active hyperaemia). Gradually returns to control level.
  4. 8. intrinsic autoregulation of vessels involves myogenic response to _______. If blood flow decreases (due to drop in pressure  resistance decreases to increase flow) if blood pressure increases, sensed by vessels, reflexive vasoconstriction to protect capillaries.
  5. 10. smooth muscle, unlike skeletal, has a poorly developed ____________ __________.
  6. 13. in smooth muscle, during an action potential, the inward flux of ions is not _________, but calcium( through receptor and voltage operated channels).
  7. 14. sheer stress caused by high velocity blood flow causes ________ levels in endothelial cells to increase . this leads to increased NO synthase actvitity , NO production, stimulates smooth muscle, cGMP production, vasodilation.
  8. 15. an increased velocity of blood flow generates sheer stress on the walls of vessels  stimulates endothelial cells to release factors that relax underlying smooth muscle (eg NO)  this counterbalances the _________ stretch response (increased pressure = reflex vasoconstriction).
  9. 16. vascular smooth muscle is controlled by: sympathetic nerves, mediators secreted by vascular endothelium, and by ___________ circulating in the blood.
  10. 17. the major neurotransmitter affecting vascular tone.
  11. 20. alpha receptors are GPCRs. NA  binds to GPCR alpha receptor  activates ________ C  IP3 produced  stimulates calcium release from SR (small amount)  stimulates calcium entry from ECF (relatively larger amount)  contraction  vessel constriction.
  12. 23. beta receptors can be found in blood vessels in skeletal muscle and ___________ circulation. When NA  beta receptors  dilation. (fight or flight)
  13. 24. under some circumstances, vascular endothelial cells may produce the vasoconstrictor __________.
  14. 25. smooth muscle cells contain a few thick myosin filaments, and many thin _____ filaments, attached to dense bodies.
  15. 26. active hyperaemia occurs when ___________ products increase in blood (adenosine, lactic acid, CO2, low oxygen levels, potassium)  stimulate vasodilation (active hyperaemia).
  16. 29. beta receptors in blood vessels mediate vaso_________. High proportion in vessels in the coronary and skeletal muscle circulation.
  17. 30. smooth muscle contractions maintain large forces, almost continually, and are very _____. Low energy costs.
  18. 31. _____________ nervous system innervates vessels.
  19. 33. in smooth muscle ,mechasnism of contraction differs from cardiac and skeletal – calcium enters cell mainly from ECF  binds to __________  activates myosin light chain kinase  phosphorylates myosin (active)
  20. 34. ______ consumption of smooth muscle 300x lower than skeletal.
Down
  1. 1. calcium moves into cell during action potential via ligand gated and _______ gated ion channels.
  2. 2. myosin light chain ______________ is an enzyme that removes phosphate from myosin (deactivates it) ending cycling. (myosin light chain kinase ADDs Pi)
  3. 4. __________ control mechinisms include neural and hormonal. Intrinsic includes local mediators/autoregulation.
  4. 5. alpha receptors when bound to noradrenaline stimulate vaso___________. GPCR  activates phospholipase C  IP3  release of calcium from SR  contraction.
  5. 7. once vascular smooth muscle has shortened, it can maintain ___________ for an even lower than normal energy cost.
  6. 9. nitric oxide is a _____ ______, a small gaseous molecule that is generated by the enzyme NITRIC OXIDE SYNTHASE (in endothelial and inflammatory cells). NO synthase activity increases in response to high Calcium levels in endothelial cells (due to sheer stress).
  7. 11. as well as nitric oxide, endothelial cells can also release vasodilatory ____________. And mediate circulating thrombin and bradykinin.
  8. 12. cAMP and cGMP help relax smooth muscle by causing ___________ of myosin light chain kinase.
  9. 18. ______________ depolarisation of smooth muscle cells produces a basal level of tone. Mechanical and chemical factors can modify this activity.
  10. 19. vasodilators include adenosine, prostacyclin and ___________  smooth muscle cell relaxation by increasing cAMP or cGMP (inactivate myosin light chain kinase).
  11. 21. circulating substances such as adrenalin, serotonin, thromboxane A2 and__________ (a major part of RAAS system), all cause vasoconstrictionvia various mechanisms increasing calcium influx.
  12. 22. the pulastile wave of contraction that keeps blood moving through vessels is known as ‘__________’. (eg in mouse tail arteriole)
  13. 27. vascular smooth muscle has calmodulin, but no ___________.
  14. 28. NA binding to beta receptors cause increased production of _____, ultimately relaxes vessel.
  15. 32. these receptors are found in vascular smooth muscle and mediate CONSTRICTION. Lower ratio in heart and skeletal muscle, higher ratio in other blood vessels eg splachnic viscera.