Salivary secretion of chromogranin A. Control by autonomic nervous system

Digestion begins with a cephalic phase that prepares the digestive system to receive food. When our brain processes visual or olfactory information about food, it triggers impulses in the cranial nerves innervating the salivary glands and stomach to prepare for food.

Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.

Overview

The cranial part of the parasympathetic division plays a crucial role in regulating the visceral functions of the head and specific structures in the neck, thoracic, and abdominopelvic cavities. Preganglionic fibers of the parasympathetic division exit the brain through cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus), delivering parasympathetic output to the respective visceral structures.
The vagus nerve (cranial nerve X) alone accounts for approximately 75...

Regulation of hormone secretion is a finely tuned orchestration driven by various types of stimuli, encompassing neural, humoral, and hormonal signals. Environmental cues instigate neural stimuli, where action potentials traverse nerve fibers to reach their designated targets. An illustrative scenario is the body's response to stress, wherein the sympathetic nervous system releases epinephrine from the adrenal glands, inducing the well-known 'fight or flight' reaction.
Humoral stimuli,...

The salivary glands, of which there are three pairs known as the parotid, submandibular, and sublingual glands, play a crucial role in maintaining oral health and initiating the digestive process. Positioned near the ears, beneath the masseter muscle, the parotid glands secrete saliva into the oral cavity through the parotid duct of Stensen. Meanwhile, the submandibular glands, located on the floor of the mouth, secrete saliva through channels named submandibular ducts. The sublingual glands,...