Conduction system of the heart

Question 1

Sinus Node (SA Node)

Answer 1

pacemaker of the heart because it has the fastest rate of automaticity (60-100 times per minute).

Question 2

Atrioventricular (AV) Node

Answer 2

: 1) It slows conduction of the impulse from atria to ventricles
to allow time for ventricular filling.

2) It has automaticity (40-60 times per minute) so it can
function as a backup pacemaker in case the sinus node fails.

3) It screens out rapid atrial
impulses to protect the ventricles from dangerously fast rates

Question 3

Bundle of His

Answer 3

• bottom of the AV node

Question 4

Bundle Branches

Answer 4

bundles of fibers
-carry the impulse into the
right and left ventricles

Question 5

Purkinje Fibers

Answer 5

hair-like fibers
-carry the impulse to ventricular muscle cells.