Some examples of visceral reflexes include coughing, sneezing, swallowing and vomiting. These reflexes are triggered by stimulation of a nerve receptor in a visceral organ.
Visceral reflexes are controlled by the autonomic nervous system and initiated in visceral organs, which are the internal organs of the chest, such as the heart and lungs, as well as the abdomen, such as the stomach and intestines. These muscles are surrounded by viscera and function with the aid of smooth muscle, which is involuntary muscle. They function independently and therefore respond only to internal triggers, such as food ingestion, or irritation, such as mucus in the lungs.
One classic example of a visceral or autonomic reflex is peristalsis. When food enters the esophagus, smooth muscle causes the viscera surrounding the entire digestive tract to rhythmically expand and contract, pushing the food through the digestive system to be further digested. Irritation of the lungs or stomach are also classic triggers of visceral reflexes. Irritation of the stomach lining can cause vomiting, and particulate matter in the lungs can cause coughing or sneezing. Like all other visceral reflexes, these are unconsciously initiated and can only be controlled by will power to a small extent, such as when holding in a cough.