Final answer:
a. Left Anterior Descending (LAD) and Circumflex. The two arteries that arise off the left main coronary artery are the Left Anterior Descending (LAD) and Circumflex arteries.
Step-by-step explanation:
The two arteries that arise off the left main coronary artery are the Left Anterior Descending (LAD) and the Circumflex arteries.
The Circumflex artery is a branch of the left coronary artery and runs along the coronary sulcus to the left side. It eventually fuses with small branches of the right coronary artery.
The Left Anterior Descending (LAD) artery is the second major branch arising from the left coronary artery. It follows the anterior interventricular sulcus around the pulmonary trunk.