This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
True about SA node is all except 
Select and explain. 
A. Supplied by nodal aery, B. Primary pacemaker, C. Supplied by left vagus nerve, D. Made up of nodal cells and connective tissue
C: Supplied by left vagus nerve
Answer: C: Supplied by left vagus nerve 
Explanation: Sinoatrial Node (SA node) It is known as the pacemaker of the hea.It generates an impulse at the rate of about 70/min and initiates the heabeat.It is horseshoe-shaped and is situated at the atriocaval junction in the upper pa of the sulcus terminalis.The impulse travels through the atrialwall to reach the AV node. Except for a pa of the left branch of the AV bundle supplied by the left coronary aery the whole of the conducting system is usually supplied by the right coronary aery. <img src=" /> REF.B D Chaurasia's human anatomy vol.1,fifth edition