A&P Chapter 17

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Author:
Shells33
ID:
277996
Filename:
A&P Chapter 17
Updated:
2014-07-01 17:52:33
Tags:
CRNA
Folders:
A&P
Description:
Local/Humoral Control of Blood Flow by Tissues
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  1. What are the 4 things tissues need?
    • 1) delivery of oxygen to tissues
    • 2) delivery of nutrients such as glucose, amino acids, etc.
    • 3) removal of CO2, H2, and other metabolites
    • 4) transport various hormones and other substances to different tissues
  2. Flow is closely related to _______.
    metabolic rate of tissues
  3. What is the mechanism for acute control of local blood flow?
    vasoconstriction/vasodilation
  4. What is the mechanism for long term control of local blood flow?
    angiogenesis
  5. What 2 things cause an acute increase in local blood flow?
    • 1) increase in tissue metabolism
    • 2) decrease in oxygen availability
  6. What are the 2 major theories for local blood flow?
    • 1) the vasodilator theory
    • 2) oxygen demand theory
  7. High altitude, pneumonia, CO poisoning, and Cyanide poisoning all cause what?
    decreased tissue oxygenation --> increased blood flow
  8. What two things determine flow through a blood vessel (Ohm's Law)?
    • 1) pressure difference between the two ends of the vessel
    • 2) resistance of the vessel
  9. What does the vasodilator theory for blood flow control say?
    • increased metabolism or decreased oxygen -->
    • increased release of vasodilators -->
    • decreased arteriole resistance -->
    • increased blood flow
  10. What does the oxygen demand theory for blood control say?
    • increase tissue metabolism or decreased oxygen delivery -->
    • decreased tissue oxygen concentration -->
    • decreased arteriole resistance -->
    • increased blood flow
  11. What are the 7 vasodilator substances released by the tissues?
    • 1) Adenosine
    • 2) CO2
    • 3) Lactic Acid
    • 4) ADP
    • 5) Histamine
    • 6) K ions
    • 7) H ions
  12. What is auto regulation of blood flow?
    the ability of a tissue to maintain blood flow relatively constant over a wide range of arterial pressures
  13. What are the 2 theories for auto regulation? Describe.
    1) Metabolic Theory

    decreased arterial pressure --> decreased delivery of oxygen and nutrients --> vasodilator substances released 

    2) Myogenic Theory

    decreased arterial pressure --> activation of intrinsic property of arterioles to dilate in response to decreased wall tension (LaPlace)
  14. According to LaPlace, increased pressure results in.....
    increased tension --> decreased radius

    ... to maintain constant flow (autoregulation)
  15. According to LaPlace, a decrease in pressure results in.....
    decreased tension --> increased radius

    .... to maintain constant flow (autoregulation)
  16. What is the most important stimulus for regulating tissue vascularity (angiogenesis)?
    oxygen
  17. What occurs in retinopathy of prematurity?
    neonates are exposed to high FiO2 levels --> degeneration of blood vessel in the retina.

    FiO2 removed --> angiogenesis which grows into vitreous humor --> blindness
  18. What 3 things does angiogenesis occur in response to? (these things cause release of angiogenic factors)
    • 1) ischemic tissues
    • 2) rapidly growing tissue (ex: tumor)
    • 3) tissue with high metabolic rates
  19. What are 4 humoral substances that cause vasoconstriction?
    • 1) Norepinephrine/Epinephrine
    • 2) Angiotensin II
    • 3) Vasopressin
    • 4) Endothelin
  20. What are 5 humoral substances that cause vasodilation?
    • 1) bradykinin
    • 2) Serotonin
    • 3) Histamine
    • 4) Prostaglandins
    • 5) Nitric Oxide
  21. Increased calcium causes...
    vasoconstriction

    calcium stimulates smooth muscle contraction
  22. Increased Potassium causes....
    vasodilation

    inhibits smooth muscle contraction
  23. Increased Magnesium causes....
    powerful vasodilation

    inhibits smooth muscle contraction
  24. Increased hydrogen ion concentration causes...
    dilation of arterioles
  25. Acetate and citrate cause....
    mild vasodilation
  26. Increased CO2 causes.... and in the brain....
    moderate vasodilation but in brain, MARKED vasodilation

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