The conduction system

Question 1

Cardiac muscle cells are self-excitable, therefore, they’re

Answer 1

autorhythmic

Question 2

Cardiac muscle cells repeatedly generate spontaneous action potentials that then trigger

Answer 2

heart contractions

Question 3

Cardiac muscle cells form the conduction system, which is the route

Answer 3

for propagating action potentials through the heart muscle

Question 4

Artificial Pacemakers are devices that ____ it includes a ______ and they are connected to

Answer 4

• sends out
  small electrical currents to
  stimulate heart to contract
  -a battery and
  pulse generator
• 1 or 2
  flexible leads threaded
  through superior vena
  cava and into chambers of
  the hear

Question 5

autorhythmic fibers in the SA node

Answer 5

natural pacemaker of the heart because they initiate action potentials most frequently

Question 6

Signals from the nervous system and hormones (like
epinephrine) can modify the heart___ and force of ___ but they do not set the fundamental rhythm

Answer 6

• rate
• contraction

Question 7

An EKG is a ____

Answer 7

recording of the electrical changes that
accompany each heart beat