cardiac cycle
what are the four phases of the cardiac cycle?
i) diastolic filling
ii) isovolumic contraction
iii) ejection
iv) isovolumic relaxation
Define stroke volume
stroke volume = the amount of blood pumped in 1 beat.
What is cardiac output?
the amount of blood pumped per minute
What happens to HR and filling time during exercise?
What increases afterload?
high blood pressure, valve stenosis
What comes first, electrical or mechanical events?
electrical events always precede mechanical events
What is the average stroke volume for an adult?
average SV = 70mL
How do you calculate cardiac output?
stroke volume x heart rate
A myocardial ischemia is this
Inadequate delivery of oxygenated blood to heart tissue (heart attack)
During diastolic filling, which valve(s) is/are open? which is/are closed?
LAP>LVP so mitral valve=open
LVP<AP so aortic valve=closed
What are the 3 factors that regulate stroke volume?
1. Preload
2. Contractility
3. Afterload
what is the average cardiac output?
5L
Acute myocardial infarction is this
Occurs when blood vessels supplying area of heart becomes blocked or ruptured
When the aortic valve is open, where is pressure higher, the aorta or the left ventricle?
If the aortic valve is open, pressure in the left ventricle must be higher than in the aorta
What is venous return?
the amount of blood entering the heart
Do older people generally have higher or lower heartrate?
higher
what is this:
-permanent blockage
-muscle cells are permanently damaged
-symptoms remain and worsen
-"heart attack"
Infarct
If the mitral valve is closed, where is pressure highest?
if the mitral valve is closed, pressure must be higher in the left atrium than in the left ventricle
What is the Frank-Starlin Law?
-stroke volume increases as EDV increases
- whatever goes in- goes out the next beat
do men or women tend to have higher heartrates
women tend to have higher heartrates than their male counterparts.
What is afterload?
the force the heart works against to eject blood