with correct answers provided
what two events are involved in heart contraction? - ✅✅1. conduction system starts and propagates
an action potential
2. cardiac muscle cels fire action potentials and contract (first in atria then ventricles)
where is the SA node? - ✅✅in right atrium inferior to superior vena cava opening
where is the AV node located? - ✅✅base of the right atrium
where is the AV bundle located? - ✅✅interventricular septum
where are the right and left bundles located? - ✅✅interventricular septum
where are the purkinje fibers located? - ✅✅ventricular walls
what does an ECG/EKG do? - ✅✅skin electrodes detect electrical signals of cardiac muscle cells?
what do p waves mean in an ECG? - ✅✅electrical changes of atrial depolarization from SA node
what does the QRS complex mean in an ECG? - ✅✅electrical changes associated with ventricular
depolarization (while atria is repolarizing)
what does a t wave mean in an ECG? - ✅✅electrical changes associated with ventricular
depolarization
what does the p-q segment mean in an ECG? - ✅✅associated with atrial cells' plateau (atria are
contracting)
, what does the s-t segment mean in an ECG? - ✅✅associated with ventricular plateau (ventricles
contracting)
what are the intervals of of ECGs? - ✅✅p-r interval, q-t interval
what is the p-r interval in an ECG? - ✅✅time from p wave to beginning of QRS deflection or atrial
depolarization to beginning of ventricular depolarization; time to transmit action potential through
entire conduction system
what is the Q-T interval in an ECG? - ✅✅time from beginning of QRS to end of T wave or reflects the
time of ventricular action potentials; length depends on heart rate
what may result from changes in the g-t interval? - ✅✅tachyarrhythmia (a rapid, irregular heart rate)
abnornmalities in the heart's electrical activity can cause what? - ✅✅heart blocks, atrial fibrillation,
ventricular fibrillation, premature ventricular contractions
what are heart blocks? - ✅✅impaired conduction; causes light-headedness, fainting, irregular heart
beat, and chest palpitations
what is atrial fibrillation? - ✅✅chaotic timing of atrial action potentials
what are ventricular fibrillation? - ✅✅chaotic electrical activity in ventricles; causes uncoordinated
contraction and pump failure
what are premature ventricular contractions? - ✅✅abnormal action potential within AV node or
ventricles
what are the two familiar hear sound? - ✅✅S1 and S2