Trace the path of the blood starting from the right atrium.
Right atrium Right ventricle Lungs (pulmonary circuit) Left atrium Left ventricle Body (systemic circuit) Right atrium
What percentage of blood remains in the venous circuit?
64%
Known as the “reservoir”
Which side of the heart works the hardest?
Left ventricle, it is the “workhorse of the heart”
Right sided heart failure leads to _______.
edema
Left sided heart failure leads to ________.
pulmonary hypertension
crackles
What 3 mechanisms return blood to the heart?
1) negative atrial pressure (inspiration)
2) constriction of veins
3) muscle contraction & venous valves
What happens to systolic BP the farther it gets from the heart?
It goes down
What is the normal systolic BP in the aorta?
120 mmHg
What is the normal systolic BP in the right atrium?
0 to -5 mmHg
How do the valves in the veins advance blood?
The muscles “milk” the veins and the valves keep the blood from flowing backward.
Define “stroke volume”.
the amount of blood the LV is able to eject in 1 contraction
Define “preload”.
the amount of pressure in the ventrical just before contraction
Define “afterload”.
the amount of pressure outside of the heart that the heart must overcome
Define “Starling’s Law”.
The more you stretch the ventrical, the harder it will contract - up to a certain point
How much blood does the average adult have?
5 Liters
T/F: In one minute the heart pumps all the blood in the body.
True
What is the formula to find cardiac output?
CO = HR x SV
Average SV is ______.
70 mL
Average HR is ______.
70 bpm
Average CO is ______.
4.9 L
What lab tests are useful to determine if symptoms are HF or lung disease?
BNP & ANP
When is BNP released?
Released by ventricles when they are overstretched.
When is ANP released?
Released by atria when they are overstretched.
BNP & ANP: Which value stays elevated and which only elevates in acute situations?
Long-term elevation: BNP
Acute elevation: ANP
(Remember the A’s, Acute = ANP)
Normal BNP value is less than _____.
100
Normal ANP value is _____.
20-77
If the pt is having trouble breathing and the BNP is normal, would you suspect a cardiac or pulmonary issue?
Pulmonary issue; if it was a cardiac issue the BNP would still be elevated.
BNP or ANP, which is the more important value?
BNP; because it stays elevated while ANP will return to normal quickly.
At what point in Starling’s Law are BNP & ANP expressed?
when the stroke volume has maxed out then starts to decline
