In most patients, the sinoatrial (SA) and atrioventricular (AV) ...

[pane00]

In most patients, the sinoatrial (SA) and atrioventricular (AV) nodes are supplied by the _____ coronary artery.
 
  a. right
  b. left main
  c. circumflex
  d. left anterior descending

Question 2

Stimulation of beta2 receptor sites results in _____.
 
  a. increased heart rate
  b. peripheral vasoconstriction
  c. constriction of renal blood vessels
  d. relaxation of bronchial smooth muscle

[Sammyo]

Answer to Question 1

A
The SA node receives its blood supply from the SA node artery that runs lengthwise through the center of the node. The SA node artery originates from the right coronary artery in about 60 of people. The AV node is supplied by the right coronary artery in 85 to 90 of the population. In the remainder, the circumflex artery provides the blood supply.

Answer to Question 2

D
Beta2 receptor sites are found in the arterioles of the heart, lungs, and skeletal muscle. Stimulation results in dilation. Stimulation of beta2 receptor sites in the smooth muscle of the bronchi results in dilation.

[pane00]

Thank you

[Sammyo]

Happy to help you