Sympathetic stimulation of nerves innervating the islets of the pancreas will:
**Core Concept**
The islets of Langerhans in the pancreas are responsible for producing various hormones including insulin and glucagon, which play a crucial role in glucose homeostasis. The autonomic nervous system, specifically the sympathetic and parasympathetic branches, modulates the secretion of these hormones through different mechanisms.
**Why the Correct Answer is Right**
Sympathetic stimulation of nerves innervating the islets of the pancreas leads to the release of glucagon, a hormone that raises blood glucose levels. This is achieved through the activation of beta-2 adrenergic receptors on the alpha cells of the islets, which in turn stimulates the release of glucagon. The sympathetic nervous system prepares the body for "fight or flight" by increasing blood glucose levels, which is essential for providing energy to the muscles.
**Why Each Wrong Option is Incorrect**
**Option A:** There is no evidence to suggest that sympathetic stimulation of pancreatic islet nerves leads to the release of insulin.
**Option B:** Parasympathetic stimulation of pancreatic islet nerves actually leads to the release of insulin, not glucagon.
**Option C:** While it is true that the sympathetic nervous system prepares the body for "fight or flight," this is not directly related to the release of glucagon from the pancreatic islets.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the autonomic nervous system modulates the secretion of hormones from the pancreatic islets, and understanding these mechanisms is crucial for managing patients with diabetes mellitus.
**Correct Answer: C. Glucagon release.**