NRSG 421 – ECGs || QUESTIONS & ANSWERS
SOLVED || 100% CORRECT!!
automaticity correct answers the ability of cardiac pacemaker cells to spontaneously initiate
an electrical impulse (Usually done by the SA node)
Na, K, Ca correct answers Normal concentrations of these electrolytes are important in
maintaining automaticity
enhanced correct answers ____________________ automaticity can cause dysrhythmias
excitability correct answers ability of cardiac cells to respond to an electrical impulse
generated by pacemaker cells or other stimuli
depolarization correct answers this occurs when the cells become electrically excited
repolarization correct answers occurs when cells return to the resting state
excitability correct answers refers to the ability of cardiac muscle cells to respond to an
outside stimulus. The stimulus can be chemical (drugs, low K/Ca), mechanical, or electrical.
sodium enters cell correct answers what electrolyte is involved in depolarization?
potassium exits cell and calcium enters correct answers what electrolyte is involved in
repolarization?
calcium enters cell correct answers what electrolyte is involved in cardiac muscle
contraction?
absolute refractory correct answers cell will not respond to further stimulation
relative refractory correct answers - vulnerable period
- some cardiac cells have repolarized and can be stimulated to respond to a stronger than
normal stimulus
bentricular depolarization and early repolarization correct answers When does the absolute
refractory period occur?
ventricular repolarization correct answers When does the relative refractory period occur?
protective mechanism correct answers The absolute refractory period is a
__________________ _________________ that prevents the cell from responding to any
type of stimulus regardless of strength.
relative refractory period correct answers During this phase, the cells can respond to a
stimulus, but it needs to be very strong. A strong stimulus can cause a response because some
cells are depolarized and some cells are repolarized (a cell that is repolarized is ready to
receive another stimulus)
SOLVED || 100% CORRECT!!
automaticity correct answers the ability of cardiac pacemaker cells to spontaneously initiate
an electrical impulse (Usually done by the SA node)
Na, K, Ca correct answers Normal concentrations of these electrolytes are important in
maintaining automaticity
enhanced correct answers ____________________ automaticity can cause dysrhythmias
excitability correct answers ability of cardiac cells to respond to an electrical impulse
generated by pacemaker cells or other stimuli
depolarization correct answers this occurs when the cells become electrically excited
repolarization correct answers occurs when cells return to the resting state
excitability correct answers refers to the ability of cardiac muscle cells to respond to an
outside stimulus. The stimulus can be chemical (drugs, low K/Ca), mechanical, or electrical.
sodium enters cell correct answers what electrolyte is involved in depolarization?
potassium exits cell and calcium enters correct answers what electrolyte is involved in
repolarization?
calcium enters cell correct answers what electrolyte is involved in cardiac muscle
contraction?
absolute refractory correct answers cell will not respond to further stimulation
relative refractory correct answers - vulnerable period
- some cardiac cells have repolarized and can be stimulated to respond to a stronger than
normal stimulus
bentricular depolarization and early repolarization correct answers When does the absolute
refractory period occur?
ventricular repolarization correct answers When does the relative refractory period occur?
protective mechanism correct answers The absolute refractory period is a
__________________ _________________ that prevents the cell from responding to any
type of stimulus regardless of strength.
relative refractory period correct answers During this phase, the cells can respond to a
stimulus, but it needs to be very strong. A strong stimulus can cause a response because some
cells are depolarized and some cells are repolarized (a cell that is repolarized is ready to
receive another stimulus)
