Lab-ECG and Heart Sounds Flashcards
what does the P-Wave represent?
depolarization of atria
what does QRS complex represent?
depolarization of ventricles
what does the T-Wave represent?
repolarization of ventricles
why don’t we see a wave that represents the repolarization of the atria?
it is masked by QRS because it happens at the same time as depolarization of ventricles
what causes the lub sound of the heart?
the turbulence associated with the closing of the AV valves
what causes the dub sound of the heartbeat?
the turbulence associated with the closing of the semilunar valves
why does the lub sound occur just after the peak of the R-wave?
the valves close right after contraction of ventricles because the blood flows in
what is the myocardium made of?
-cardiac muscle
-has characteristics of both skeletal and smooth muscle
what does autorhythmic mean?
generates its own action potentials
steps for action potentials being spread through the heart
- AP originate in SA node
- spread thru atria (causing contraction of atria)
- AP reach the AV node (get delayed here for a short amt. of time)
- pass thru right and left bundle branches, bundle of His, and Purkinje fibers
- spread through the ventricles (causes contraction of ventricles
most common ECG type?
12-lead ECG
calculating heart-rate in BPM
large block: 300/large block sections
small block: 1500/small squares
