5 steps of system

Question 1

Step 1

Answer 1

SA node activity
and atrial
activation begin.
Time= 0 sec

Question 2

Step 2

Answer 2

Stimulus spreads across
the atrial surfaces and
reaches the AV node.
Time= 50 msec

Question 3

Step 3

Answer 3

There is a 100-msec delay
at the AV node. Atrial
contraction begins

Time- 150 msec

Question 4

step 4

Answer 4

The impulse travels along
the interventricular septum
within the AV bundle and
the bundle branches to the
Purkinje fibers and, via the
moderator band, to the
papillary muscles of the
right ventricle.

Question 5

Step 5

Answer 5

The impulse is distributed
by Purkinje fibers and
relayed throughout the
ventricular myocardium.
Atrial contraction is
completed, and ventricular
contraction begins.

Time= 225 msec