Pressure volume cycles Flashcards
What hormones do the kidneys make
Renin and ACE
What percentage of adult body mass is the skeletal muscle
40%
What does the skeletal muscle pump do
Augments venous return
4 stages of cardiac cycle
Ventricular filling
Isovolumic ventricular contraction
Ejection
Isovolumic ventricular relaxation
Which valves close at S1
AV valves close
Which murmurs are systolic
AV stenosis (aortic) SL regurgitation (mitral)
Which filament is thick and which filament pulls which
Myosin (is a motor protein)
Myosin pulls actin
Is a cardiac action potential longer or shorter
Longer - Ca2+ and K+ flow during plateau phase
Names of the stages in an action potential of a cardiac myocyte (0, 1, 2, 3, 4)
0 = rapid depolarisation 1 = transient outward 2 = plateau phase 3 = rapid repolarisation 4 = resting potential
How long is a cardiac action potential
500 ms
How are APs in SA and AV node triggered
Spontaneously - no inward rectifier, so not stable at rest
Transient increase in inward Ca2+ causes upstroke of AP
What initiates repolarisation in SA node AP
Increase in K conductance
Resting potential in SA node cells
There is no official resting potential - it is unstable and close to threshold
SA node cells are autorhythmic
Pacemaker potential
Voltage drifts positive between nodal beats (no inward rectifiers)
Slope of PP determines rate of firing
Which channels does the electrical current of funny current flow through
HCN channels - not sodium
