This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Sympathetic stimulation of nerves innervating the islets of the pancreas will: 
Select and explain. 
A. Have no effect, B. Increase secretion of insulin from B cells, C. Decrease secretion of insulin from B cells, D. Increase secretion of glucagon from A cells
D: Increase secretion of glucagon from A cells
Answer: D: Increase secretion of glucagon from A cells 
Explanation: The pancreatic islets receive innervation from both the sympathetic and parasympathetic nervous system. Stimulation of the parasympathetic system increases secretion of insulin from the B cells. Stimulation of the sympathetic system increases glucagon secretion from the A cells. Insulin is inhibited by sympathetic stimulation. Ref: Molina P.E. (2013). Chapter 7. Endocrine Pancreas. In P.E. Molina (Ed),Endocrine Physiology, 4e.