Cardiovascular fundamentals overview Flashcards
Five functions of the myocardium
- chronotropy
- dromotropy
- inotropy
- bathmotropy
- lusitropy
Chronotropy is the ability to
generate an electrical impulse at an intrinsic site
dromotropy is the
speed and ability to facilitate electrical impulse conduction
inotropy is the ability
to contract in relation to a given preload, afterload, and heart rate
bathmotropy is the demonstration
of an intrinsic excitatory threshold
lusitropy is the
relaxation of the myocardium, independent from termination of contraction.
preload is the
volume of blood in a ventricular cavity at the end of diastole immediately before contraction, imparting stretch on a resting myocardial sarcomere
afterload is the
pressure that a VENTRICLE must overcome to generate cardiac output. The greater the afterload (vascular resistance or impedance), the greater the amount of energy and force required to enable ejection of blood from a ventricle and vice versa.
Action potential phase 0 electrolyte movement and conduction change
Na influx into the cell. depolarization
action potential phase 1 electrolyte movement and conduction change
refractory Ca and Cl into the cell. effective refractory period
action potential phase 2 electrolyte movement and conduction change
Ca into the cell and K out of the cell. effective refractory period
action potential phase 3 electrolyte movement and conduction change
K out of the cell. repolarization
action potential phase 4 electrolyte movement and conduction change
resting membrane potential.
p wave represents
SA node impulse generation
PR interval
duration for conduction to occur from the sa node through the AV node, bundle of HIS, bundle brances, and purkinje fibers
