Heart and Circulation Flashcards
What are the two atrioventricular valves in the heart?
tricuspid (right)
bicuspid (left)
What are the semilunar valves? What do they do?
pulmonary and aortic valves
- prevent backflor from aorta/pulm arteries into ventricles during diastole
Which valves are open during systole?
semilunar: since blood is getting pushed out
What is ESV?
End systolic volume: blood that’s left over in the ventricals after pumping blood out (~50ml)
What is EDV?
End diastolic volume; how much blood is in ventricles after diastole (~120ml)
What is diastole: what happens?
period of filling the ventricles: atria contract, semilunar valves are closed (AV valves open so ventricles can get filled)
Atrial contraction accounts for how much of ventricle filling?
20-30%
What are the two main arteries of coronary circulation, and where do they branch off of?
left and right coronary arteries, branching off of aorta
The coronary arteries supply the heart muscle of course (ventricles/atrium), but what else that is essential to the heart?
conducting system
An interruption of the circumflex artery would impact what side of the heart?
left ventricle/atrium
What receives the deoxygenated blood used by the heart, and where does it dump into?
coronary sinus -> dumps into right atrium
If myocardial oxygen supply is less than myocardial oxygen demand (MVO2), what can happen?
ischemia
Describe the conducting system of the heart.
1) SA node: first node, at superior vena cava/right atrium jxn
2) AV node: at right atrium/right ventricle jxn
- into interventricular septum, where we go to:
3) Bundle of His -> RBB and LBB
4) Purkinje tissue/fibers in ventricles
What is known as the main pacemaker of the heart?
SA node
What is a normal stroke volume range?
55-100ml
What does stroke volume depend on? (3)
1) preload (how much blood is in L ventricle after filling, aka LVEDV)
2) contractility (ability of L ventricle to contract)
3) afterload (the aortic pressure against which the L ventricle must overcome to pump blood out of the heart)
How do you get cardiac output? (equation)
HR x SV = CO
What is cardiac output?
the amount of blood discharged from the R or L ventricle per minute (time component)
vs SV: amount of blood ejected with each myocardial contraction (amount!!)
What is a normal CO value?
4-5L /minute
What is EF and what is a normal value?
EF = stroke volume/LVEDV
- % of available blood in LV that is pushed out for use
normal = >55%
Does diastolic fill time increase or decrease with heart disease and increased HR?
decreases
What is MVO2?
myocardial oxygen demand
What causes MVO2 to increase?
activity, increased HR or BP
What influences arterial pressure?
usually high pressure system
- can change based on peripheral resistance (are arteries dilated/contracted) and/or elasticity of vessels (think anneurism)
