Quiz 1 Flashcards
What two factors principally determine the cardiac output?
Heart Rate
Stroke Volume
What are LVEDV and LVESV?
LVEDV- Left ventricular end diastolic volume
LVESV- Left ventricular end systolic volume
What is the formula for stroke volume?
SV = LVEDV - LVESV
What is the formula for Ejection fraction (EF)?
EF = SV / LVEDV
What is the range for a normal ejection fraction?
55-70%
What is the general definition of preload?
What is the definition of preload as it pertains to the heart? What factor primarily determines preload?
What is the definition of afterload as it pertains to the heart? What is it often approximated by?
What is contractility in the heart? What nervous system regulates contractility? What effect does it have on ESV (LVSEV)?
What is venous return?
What are the three main factors that affect venous return?
1) Right atrial pressure
- decreased RAP increases VR
2) Mean systemic filling pressure
- Increased MSFP increases venous return
3) Total peripheral resistance
-Decreased TPR increases venous return
What is right atrial pressure? What is the normal range? What can cause it to decrease/increase?
What is MSFP? What causes it to increase/decrease?
What proportion of resistance to venous return is determined by arteriolar/small artery resistance? What proportion by venous resistance?
What is the resting membrane potential for a contractile cardiac mucle cell?
-80 mV
What occurs during phase 4 of a ventricular myocyte action potential?
What occurs during phase 0 of a ventricular myocyte action potential?
What occurs during phase 1 of a ventricular myocyte action potential?
What occurs during phase 2 of a ventricular myocyte action potential?
What occurs during phase 3 of a ventricular myocyte action potential?
What occuring during phase 4 of a ventricular myocyte action potential?
What event during a cardiac myocyte action potential induces muscle contraction?
In a healthy heart, the only viable pathway for electrical signaling between the atria and the ventricles is what structure?
The bundle of His
Myocytes specializing in conduction have notably smaller levels of what two contractile proteins?
Myosin and Actin