cardiac electrophysiology

Question 1

are the cells that make up the conduction system muscle or nerve cells

Answer 1

muscle

Question 2

what does the SA node act as

Answer 2

pacemaker

Question 3

what happens after electrical excitation

Answer 3

contraction

Question 4

what is normal sinus rhythm

Answer 4

60-100bpm

Question 5

what does depolarisation trigger

Answer 5

depolarisation of atrial myocardium

Question 6

how do cells in heart communicate

Answer 6

via gap junctions

Question 7

what does an impulse in the heart behave as

Answer 7

a syncytium

Question 8

what happens to a pulse originating anywhere in the myocardium

Answer 8

it will propagate throughout the heart

Question 9

what innervates the SA node

Answer 9

sympathetic and parasympathetic system

Question 10

where is SA node found

Answer 10

right atrium

Question 11

what is technical word for contraction

Answer 11

depolarisation

Question 12

what happens during P wave on ECG

Answer 12

atrial depolarisation

Question 13

what happens during Q,R,S wave on ECG

Answer 13

ventricle depolarisation

Question 14

what happens during T wave on ECG

Answer 14

repolarisation

Question 15

how to tell normal sinus rhythm on ecg

Answer 15

equal gaps between spikes

Question 16

how to tell sinus arrhythmia on ecg

Answer 16

not equal gaps between spikes

Question 17

conc of sodium inside and outside the cell

Answer 17

high outside, low inside

Question 18

conc of potassium inside and outside cell

Answer 18

low outside, high inside

Question 19

what creates the resting membrane potential

Answer 19

differences in charges inside and outside the cell

Question 20

what type of depolarising cells are there

Answer 20

fast ones
slow ones (pacemaker cells)

Question 21

what does sodium entering the cell (depolarisation) cause

Answer 21

Calcium and potassium channels to open

Question 22

differences in conduction in slow and fast depolarising cells

Answer 22

slow is less stable than fast
slow has lower RMP than fast

Question 23

what does higher resting potential mean

Answer 23

fewer sodium channels reset which means slower upstroke on graph

Question 24

effect of vagal stimulation on graph

Answer 24

• slows it down
• resting potential more negative
• pacemaker current is slower

Question 25

catecholamine effect of graphs

Answer 25

• makes resting potential more excited
• they appear closer together
• speed the pacemaker current

Question 26

effect of vagal stimulation on graph

Answer 26

resting membrane potential is lowered

Question 27

effect of adrenergic stimulation on graph

Answer 27

• closer together
• resting membrane potential is higher

Question 28

can temperature influence pacemaker rate

Answer 28

yes as temp increases so does heart rate