cardiac electrophysiology Flashcards
are the cells that make up the conduction system muscle or nerve cells
muscle
what does the SA node act as
pacemaker
what happens after electrical excitation
contraction
what is normal sinus rhythm
60-100bpm
what does depolarisation trigger
depolarisation of atrial myocardium
how do cells in heart communicate
via gap junctions
what does an impulse in the heart behave as
a syncytium
what happens to a pulse originating anywhere in the myocardium
it will propagate throughout the heart
what innervates the SA node
sympathetic and parasympathetic system
where is SA node found
right atrium
what is technical word for contraction
depolarisation
what happens during P wave on ECG
atrial depolarisation
what happens during Q,R,S wave on ECG
ventricle depolarisation
what happens during T wave on ECG
repolarisation
how to tell normal sinus rhythm on ecg
equal gaps between spikes
how to tell sinus arrhythmia on ecg
not equal gaps between spikes
conc of sodium inside and outside the cell
high outside, low inside
conc of potassium inside and outside cell
low outside, high inside
what creates the resting membrane potential
differences in charges inside and outside the cell
what type of depolarising cells are there
fast ones
slow ones (pacemaker cells)
what does sodium entering the cell (depolarisation) cause
Calcium and potassium channels to open
differences in conduction in slow and fast depolarising cells
slow is less stable than fast
slow has lower RMP than fast
what does higher resting potential mean
fewer sodium channels reset which means slower upstroke on graph
effect of vagal stimulation on graph
- slows it down
- resting potential more negative
- pacemaker current is slower
catecholamine effect of graphs
- makes resting potential more excited
- they appear closer together
- speed the pacemaker current
effect of adrenergic stimulation on graph
- closer together
- resting membrane potential is higher
can temperature influence pacemaker rate
yes as temp increases so does heart rate
