Ch17FlashCards.txt

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Author:
radracer43
ID:
278091
Filename:
Ch17FlashCards.txt
Updated:
2014-07-03 11:43:49
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CRNA
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A&P Test 4
Description:
A&P Chapter 17
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  1. Tissues control blood flow in proportion to what 4 needs?
    • Delivery of oxygen
    • Delivery of nutrients
    • Removal of CO2 and H+ and other metabolites
    • Transport of various hormones and other substances to different tissues
  2. Flow is closely related to what?
    Metabolic rate of tissues
  3. Acute control of local blood flow is determined by what structures?
    • Arterioles
    • Metarterioles
    • Precapillary sphincters
  4. What 2 factors primarily alter tissue blood flow?
    • 1) Tissue metabolism
    • 2) Oxygen availability
  5. What are the 2 major theories for local blood flow?
    • 1) The vasodilator theory
    • 2) Oxygen demand theory
  6. How does increased tissue metabolism affect blood flow?
    Increases flow
  7. How does decreased oxygen concentration affect blood flow?
    Increases flow
  8. What law represents the relationship between pressure, flow, and resistance?
    • Ohm's law
    • ?P/R = Q
  9. Describe the Vasodilator Theory for blood flow control
    Increase in metabolism/Decrease in oxygenation leads to release of vasodilators causing decreased resistance and increased flow
  10. Describe the Oxygen Demand Theory for blood flow control
    Increase in metabolism/decrease in oxygenation leads to decrease tissue oxygen concentration causing decreased resistance and increased flow
  11. Define autoregulation
    The ability of a tissue to maintain blood flow relatively constant over a wide range of arterial pressures
  12. List examples of vasodilators involved in the Vasodilator Theory for blood flow control
    Adenosine, CO2, lactic acid, ADP compounds, histamine, K+ ions, H+ ions
  13. What is the Metabolic Theory of autoregulation?
    Decreased arterial pressure leads to decreased oxygen and nutrient delivery which releases vasodilator(s)
  14. What is the Myogenic Theory of autoregulation?
    As arterial pressure falls, arterioles have intrinsic property to dilate in response to the decrease in wall tension
  15. Explain LaPlace's Law as it relates to the Myogenic Theory of autoregulation.
    • As pressure increases, the increase in tension will cause a decrease in vessel radius
    • As pressure decreases, the decrease in wall tension will cause an increase in vessel radius
  16. Is long-term or short-term control of flow more effective?
    Long-term
  17. How does long-term blood flow regulation occur?
    By changing the size and number of vessels - angiogenesis
  18. How does high altitude affect angiogenesis?
    Increased vascular growth in tissues in response to decreased oxygen levels
  19. What is the process of retrolental fibroplasia or retinopathy of prematurity?
    High FiO2 decreases vessel growth or even causes degeneration. When the high oxygen concentration is removed, there is a proliferation of retinal vessels into the vitreous humor causing blindness
  20. What is the result of chronically overactive tissue with regards to blood flow/vessels?
    Increase in both number and size of arterioles and capillaries to match needs of tissue
  21. Define angiogenesis
    Growth of new blood vessels
  22. What 3 factors stimulate angiogenesis?
    • Ischemic tissue
    • Rapidly growing tissue
    • Tissue with high metabolic rate (tumors)
  23. What are examples of angiogenic factors?
    • Vascular endothelial cell growth factor (VEGF)
    • Fibroblast growth factor (FGF)
    • Angiogenin
  24. What are examples of vasoconstrictors involved in humoral regulation of blood flow?
    • Norepinepherine
    • Epinepherine
    • Angiotensin II
    • Vasopressin (ADH)
    • Endothelin
  25. What are examples of vasodilators involved in humoral regulation of blood flow?
    • Bradykinin
    • Serotonin
    • Histamine
    • Prostaglandin
    • Nitric oxide
  26. How do calcium ions affect blood flow?
    Increased levels cause vasoconstriction through smooth muscle contraction
  27. How do potassium ions affect blood flow?
    Increased levels cause vasodilation through smooth muscle inhibition
  28. How do magnesium ions affect blood flow?
    Increased levels cause profound vasodilation through smooth muscle inhibition
  29. How do hydrogen ions affect blood flow?
    • Increased levels cause vasodilation
    • Decreased levels cause vasoconstriction
  30. How do anions like citrate and acetate affect blood flow?
    Both cause mild vasodilation
  31. How does carbon dioxide concentration affect blood flow?
    Increases cause moderate vasodilation in most tissues; profound vasodilation in the brain

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