Cardio Test 1

Question 1

Gap Jxn

Answer 1

Allow muscle action potential to conduct from 1 muscle fiber to its neighbors

• These gap Jxn are what help the entire myocardium of the Altria or ventricles to contract as a single unit

Question 2

Desmosomes

Answer 2

Hold fibers together

Question 3

Cardiac Output

Answer 3

CO=SV X HR

Volume of blood ejected from LV or RV into the aorta or pulmonary trunk each minute

Question 4

Conduction System: SA node

Answer 4

Propagates through intermodal pathways in right atria

-anterior intermodal - tract of Brachmann
This pierces the interatrial septum and sends the impulse to LA
Allows simultaneous atrial contraction

• middle intermodal - Tract of wenkebach
• Posterior intermodal - tract of there’ll

Question 5

Conduction System: AV node

Answer 5

• Located in/near the interatrial septum, anterior to the opening of the coronary sinus
• Action potential slows considerably at the AV Node due to various differences in cell structure of the node
• Delay provides time for the atria to empty blood into the ventricles and let them start filling

Question 6

Conduction System: AV Bundle

Answer 6

• Known as “Bundle of His”
• Only site where action potential propagate from atria to ventricles in normal heart
  • -Because everywhere else, the fibrous skeleton of the hear insulates the atria from the ventricles

Question 7

Conduction System: AV Bundle enters and branches where?

Answer 7

Action potential enters right and left bundle branches

Question 8

Conduction System: Right and left AV bundle branches next reach

Answer 8

Action potential reaches large-diameter Purkinje fibers

-Rapidly conducts action potential beginning at the apex upwards to remainder of the ventricular myocardium

Question 9

Conduction System: Purkinje fibers cause

Answer 9

Ventricles to contract