NR 507 MIDTERM ADVANCED PATHOPHYSIOLOGY TESTED
QUESTIONS AND COMPLETE SOLUTIONS
◉ What is the formula for cardiac output
Answer: CO = HR x SV
◉ cardiac reserve
Answer: difference between resting and maximal CO; should be about 4-5x as high but does decrease
1% per year after age 30
◉ What type of relationship does heart rate and stroke volume have?
Answer: inverse
low HR = longer fill time = increase stroke volume
high HR = lower fill time = lower stroke volume
,◉ What is preload?
Answer: the degree of stretch on the heart before it contracts/ amount of blood entering the ventricles
during diastole
◉ average amount of preload?
Answer: 120-130 mls
◉ When fibers stretch during diastole how does that effect contraction?
Answer: contraction is stronger
◉ What happens when cardiac fibers overstretch during diastole?
Answer: decreased contraction due to fibers being unable to snap back
◉ What can cause increased preload
Answer: CHF and hypervolemia
,◉ What can cause decreased preload
Answer: cardiac tamponade and hypovolemia
◉ What are two common causes of hypovolemia
Answer: dehydration and hemorrhage
◉ Afterload
Answer: the amount of resistance to open the semilunar valves and eject of blood from the ventricle
◉ what influences afterload (3)
Answer: ventricle wall thickness (muscle strength)
arterial pressure (resistance to ejection)
ventricle chamber size (blood volume capacity)
, ◉ what can cause an increase in afterload
Answer: systemic hypertension
valve disease
COPD (pulmonary hypertension)
◉ what can decrease afterload
Answer: hypotension or vasodilation
◉ what influences cardiac contractility (inotropic state)
Answer: levels of electrolytes
High levels of ATP
level of oxygen available
synchronous muscle contraction
◉ What electrolytes are used for cardiac muscle contraction?
QUESTIONS AND COMPLETE SOLUTIONS
◉ What is the formula for cardiac output
Answer: CO = HR x SV
◉ cardiac reserve
Answer: difference between resting and maximal CO; should be about 4-5x as high but does decrease
1% per year after age 30
◉ What type of relationship does heart rate and stroke volume have?
Answer: inverse
low HR = longer fill time = increase stroke volume
high HR = lower fill time = lower stroke volume
,◉ What is preload?
Answer: the degree of stretch on the heart before it contracts/ amount of blood entering the ventricles
during diastole
◉ average amount of preload?
Answer: 120-130 mls
◉ When fibers stretch during diastole how does that effect contraction?
Answer: contraction is stronger
◉ What happens when cardiac fibers overstretch during diastole?
Answer: decreased contraction due to fibers being unable to snap back
◉ What can cause increased preload
Answer: CHF and hypervolemia
,◉ What can cause decreased preload
Answer: cardiac tamponade and hypovolemia
◉ What are two common causes of hypovolemia
Answer: dehydration and hemorrhage
◉ Afterload
Answer: the amount of resistance to open the semilunar valves and eject of blood from the ventricle
◉ what influences afterload (3)
Answer: ventricle wall thickness (muscle strength)
arterial pressure (resistance to ejection)
ventricle chamber size (blood volume capacity)
, ◉ what can cause an increase in afterload
Answer: systemic hypertension
valve disease
COPD (pulmonary hypertension)
◉ what can decrease afterload
Answer: hypotension or vasodilation
◉ what influences cardiac contractility (inotropic state)
Answer: levels of electrolytes
High levels of ATP
level of oxygen available
synchronous muscle contraction
◉ What electrolytes are used for cardiac muscle contraction?
