PHYS-Heart as a Pump

  1. Outline the direction of blood flow:
    Right atrium -> tricuspid valve -> Right ventricle -> pulmonary valve to pulmonary circulation -> left atrium -> mitral valve (bicuspid) -> left ventricle -> aortic valve to aorta
  2. Valve opens passively/actively to pressure changes in ventricle?
    Passively
  3. What are the two major stages of the cardiac cycle?
    Diastole and systole
  4. What happens with volume when in diastole?
    Volume increases
  5. What happens with volume when in systole?
    Volume decreases
  6. What happens to the rate ventricular filling in the beginning of diastole?
    Rapid
  7. What happens to the rate of ventricular filling at the end of diastole?
    Slows down
  8. What is systole?
    Ventricular contraction – blood shoots out/eje from ventricles
  9. What is diastole?
    Ventricular relaxation – filling
  10. What happens to pressure when blood fills up a chamber?
    Pressure increases
  11. What happens when there is increased pressure in the atria?
    AV valve opens
  12. What’s the cardiac output when the venous return is zero?
    Zero. Heart can only pump out what it receives
  13. What is the venous return when at mean systemic pressure?
    Venous return is zero
  14. What happens to venous return when the right atrial pressure increase?
    Venous return decreases
  15. When right atrial pressure increases, what happens with left ventricular end diastolic volume?
    Increases
  16. When right atrial pressure increases, what happens to stroke volume and cardiac output?
    They both increase
  17. As venous return increases, what happens to right atrial volume and pressure?
    They both increase
  18. What is a positive inotropic agent and what is its function?
    • Increase cardiac output- ie norepinephrine, digoxin
    • Achieve a new steady state that is at a lower right atrial pressure- which would increase venous return and match cardiac output
  19. What happens to the mean systemic pressure when blood volume increases?
    Pressure increases too
  20. What happens to venous return with increased blood volume?
    Venous return increases – meaning increase cardiac output by increasing right atrial pressure that pushes blood forward
  21. What happens to mean systemic pressure and venous return with decreased blood volume?
    Both decrease
  22. What happens to afterload and cardiac output with increased total peripheral resistance?
    Increase afterload and decrease cardiac output
  23. When’s to venous return with increased total peripheral resistance?
    Reduced. Because blood flows slower from arterial to venous side
  24. Does the right atrial pressure change with increased total peripheral resistance?
    No

    • Does the right atrial pressure change with decreased total peripheral resistance?
    • No
  25. Does mean systemic pressure change with changes in total peripheral resistance?
    No
  26. What happens to venous return and cardiac output with decreased total peripheral resistance?
    Increase to both, Blood flows at a faster rate from arterial to venous side
  27. What happens to afterload with decreased total peripheral resistance?
    Decrease
  28. At low end-diastolic volume, what is the overlap of actin and myosin?
    Too much overlap, leading to low stroke volume because ventricles unable to contract well
  29. What results at TOO high end-diastolic volume?
    Left ventricle dysfunction because not enough overlap to generate force
  30. What is preload?
    The amount of stretch on the walls of the ventricle
  31. What is the relationship between end diastolic volume and ventricular wall stretch?
    End diastolic volume increases stretch on the walls of the ventricle
  32. What is the stroke volume when heart rate is low?
    Stroke volume is high because the ventricle has more time to fill allowing greater end diastolic volume
  33. What happens to end diastolic volume when heart rate is high?
    EDV goes down
  34. What is the relationship between heart rate, stroke volume and cardiac output?
    CO= SV x HR
  35. What is the relationship between heart rate and cardiac output?
    Parabolic
  36. What is afterload?
    The amount of pressure against which the heart pumps
  37. What happens to afterload with increased thickness of the ventricular wall?
    Afterload decrease – greater force of contraction of the ventricle
  38. What happens to afterload with large chambers (chambers with large radius)?
    Afterload increases- ventricle has to work harder to pump the blood out
  39. Is increase afterload good or bad on the heart?
    Bad- as in, the ventricle has to work harder to pump the blood out. Makes it difficult to shorten the sarcomeres, requires more ATP and therefore myocardial oxygen demand
  40. Does a positive inotropic agent increase or decrease in contractility of the heart?
    Increase
  41. Which receptor do positive inotropic agents act on?
    Adrenergic agonists act through beta 1 receptors
  42. True/False: veins are more compliant than arteries
    True
  43. What happens to venous pressure when there is an increase in venous volume?
    Not significant change in pressure, because veins are compliant
  44. What happens to a rate rail pressure when there isi an increase in arterial volume?
    Significant increase in pressure because of low compliance
  45. What happens to the stroke volume in aortic stenosis?
    Stroke volume goes down because aortic valve is narrowed
  46. What happens to systolic pressure in aortic stenosis?
    Systolic pressure goes down
  47. True/False: aortic valve closes at higher pressure than when it opens
    True
  48. What happens to stroke volume when there is an increased afterload?
    Stroke volume decreases
  49. What happens to resistance when the radius of the vessel is reduced?
    Resistance increase
  50. What equation shows the relationship between pressure, flow and resistance?
    P= QxR
  51. What is the relationship between length of vessel and resistance?
    Directly proportional
  52. What happens to flow with increased radius?
    Flow increase
  53. Veins have thin or thick wall?
    Thin
  54. Do veins have high or low pressure?
    Low pressure due to high compliance
  55. Do arteries have thick or thin wall?
    Thick wall
  56. Which side has more volume, venous or arterial?
    Venous side
  57. What is vessel compliance?
    The distensibility of the vessel

    • Sympathetic nervous systems reduce Or increase compliance in both arteries and veins?
    • Reduce compliance
  58. True/False: aging veins are still more compliant than young arteries?
    True
  59. Slope of which type of graph shows compliance?
    • V/P
    • Pressure on x axis
    • Volume on y axis
  60. What is the equation used to determine mean arterial pressure?
    MAP= 1/3 systole + 2/3 diastole
  61. In aortic stenosis what happens with stroke volume and pressure?
    Volume ejected goes down and systolic pressure may go down too
  62. What happens to systolic pressure in arteriosclerosis?
    Compliance reduce, so systolic pressure increase
Author
lykthrnn
ID
344767
Card Set
PHYS-Heart as a Pump
Description
Cardiovascular midterm
Updated