A&P Chapter 13

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A&P Chapter 13
2010-05-12 09:11:35

Medic11 A&P Chapter 13
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  1. Arteries
    • Carry blood away from the heart
    • Branch repeatedly & decrease in size until they become arterioles
  2. Arterioles
    Small branches off arteries that empty into capillaries
  3. Vasomotion
    Blood flow within any one capillary is intermitent rather than a steady and constant stream
  4. Veins
    vessels that collect blood from all tissues and return it to the heart
  5. Venules
    Smallest veins collect blood fr capillaries and then merge into medium sized and then lg veins
  6. Three layers in the walls of arteries and veins
    • Tunica Interna
    • Tunica Media
    • Tunica Externa
  7. The walls of arteries are thicker than the walls of veins. T or F
  8. Three vessels in the arterial system
    • Lg elastic arteries
    • Medium sized muscular arteries
    • Small arterioles
  9. What happens to the vessels as blood procedes toward the capillaries
    • The number of vessels increases
    • Diameter of vessels decreases and walls become thinner
  10. What are the only vessels that allow exchange between blood and interstitial fluid?
  11. Capillary Beds
    Interconnected networks of capillaries
  12. Precapillary Sphincter (band of smooth muscle)
    Adjusts blood flow into each capillary
  13. Explain pressure and valves in the vessels
    • Pressure in the arterial system is high
    • Pressure in veins is much lower
    • Valves prevent backflow
  14. Pressure and flow
    Blood will flow from an area of higher pressure to an area of lower pressure
  15. Circulatory pressure Vs total peripheral resistance
    In order for circulation to occur circulatory pressure must higher than the resistance in the system on a whole
  16. Blood pressure (arterial Pressure) Vs peripheral resistance (resistence of the arterial system)
    For blood to flow into peripheral capillaries blood pressure (arterial pressure) must be greater than peripheral resistance (resistance of the arterial system)
  17. What regulates BP?
    Neural and hormonal ctrl mechanisms
  18. What are the effects ventricular systole and diastole on arterial pressure?
    Arterial pressure rises during systole and falls during diastole
  19. what is the term for the difference between systolic and diastolic pressure?
    Pulse pressure
  20. What assists low pressure veins in poropelling blood toward the heart?
    • Valves
    • Muscular Compression
    • Respiratory Pump
  21. Homeostatic mechanisms ensure that tissue blood flow (tissue perfusion) delivers adequate ________& _______.
    Oxygen and nutrients
  22. Three things that cause variations in blood flow
    • Cardiac output
    • Peripheral resistance
    • Blood Pressure
  23. What are the three influences on coordinated regulation of cardiovascular function?
    • Autoregulation
    • Neural mechanisms
    • Endocrine mechanisms
  24. Autoregulation
    Local factors that change the pattern of blood flow within capillary beds in response to chemical changes in interstitial fluids
  25. Neural Mechanisms effect on cardiovascular function
    CNS mechanisms respond to changes in arterial pressure or blood gas levels
  26. Hormones effect on cardiovascular function
    • Assist in short term adjustments such as changes in CO and peripheral resistance
    • Assist in long term adjustments ie changes in blood vol that affect CO and gas transport
  27. How is peripheral vessel resistance adjusted
    By dilation or constriction of precapillary sphinters
  28. Baroreceptor Reflexes
    Autonomic reflexes that adjust cardiac output in peripheral resistance to maintain normal arterial pressures
  29. Chemoreceptor Reflexes
    • Respond to changes to the oxygen or CO2 levels in the blood or CF
    • Sympathetic stimulation leads to stimulation of cardio acceletory & vasomotor ctrs
    • Parasympathetic activation stimulates the cardioinhibitory ctr
  30. Endocrine sys provides short term reg of CO and peripheral resistance with ___ & ____ that come fr the ____ ____.
    • Epi
    • Norepi
    • Adrenal Medullae
  31. 4 hormones that have long term regulation on BP and Blood volume are
    • Antidiuretic Hormone (ADH)
    • Angiotensin II
    • Erthropoietin (EPO)
    • Atrial natriuetic peptide (ANP)
  32. Effects of ADH
    • Promote peripheral vasoconstriction
    • Water and electrolyte retention
    • Stimulate thirst
  33. Efffect of angiotensin II
    Peripheral vasoconstriction
  34. Effects of Erthropoietin (EPO)
    Stimulates red blood cell production
  35. Effects of Arterial Natriuretic Peptide
    • Encourages sodium and fluid loss
    • Reduces BP
    • Inhibits thirst
    • Lowers peripheral resistance
  36. In the body blood loss causes
    • Increase cardiac output
    • Mobilization of venous reserves
    • Peripheral vasoconstriction
    • Liberation of hormones that promote fluid retention and production of RBCs