sem 2: cardiac cycle Flashcards
what is phase 4 at SAN
If funny channels
hyperpolarisation will activate Na channels causing influc
what is phase 0 at SAN
depolarisation
activation of Ca channels causing influx
what is phase 3 at SAN
repolsarisation
activation of K channels causing efflux
what is phase 0 at muscle cells
Vg Na activated by depolarisation causing influx
Vg Ca starts to open slowly
what is phase 1 at muscle cells
na channels close
what is phase 2 in muscle cells
vg ca channels fully open- calcium influx
CICR
vg K start to open slowly
what is phase 3 in muscle cells
rapid repolarisation
Vg Ca close
K open fully- efflux
what is phase 4 in the muscle cells
resting phase
Na/K pump
what is the p wave
atrial depolarisation
what is the PR segment
AV nodal delay
what is the QRS segment
ventricular depolarisation
what is the ST segment
time during which ventricles are contracting and emptying
what is the T wave
ventricular repolarisation
what is the TP interval
time when ventricles are filling and relaxing
what are the two parts of systole
ventricular isovolumetric contraction
ventricular contraction and ejection
what is isovolumetric contraction
when volume doesnt change but due to contrcation, pressure increases
what is ventricular contraction
pressure increases abover pulmonary and aorta and valves open
what is isovolumetric relaxation
kinetic energy of blood is lost
closed chamber
pressure decreases
what is EDV
volume left in ventricles after diastole (right before ejection)
what is ESV
volume left after ejection of blood
how do you calculate stroke volume
SV= EDV-ESV
what is the ejection fraction
SV/ EDV
what is stroke work
tells us amount of energy used (oxygen) during cardiac cycle
right sided heart failure
pressures in right atria raised less blood ejected from RV higher ESV atria pumps against greater pressure height of venous distention is increased
what is S1
the sound of tricuspid and mitral closing at beginning of ventricular systole
what is S2
sound of aortic and pulmonary closing at beginning of ventricular diastole
what is S3
turbulent blood flow into ventricles
what is S4
forceful atrial contraction against a stiff ventricle
