Enteric nervous system

The enteric nervous system (ENS), often called the "second brain," is an intrinsic nervous system of the gastrointestinal tract. It's a complex network of neurons and glial cells embedded in the walls of the esophagus, stomach, small intestine, and large intestine.

The ENS controls many digestive functions independently of the central nervous system (CNS), although it is modulated by the autonomic nervous system. Its primary functions include:

• Motility: It regulates the muscular contractions of the gut wall, controlling peristalsis and segmentation.
• Secretion: It controls the release of digestive enzymes, hormones, and mucus from the glands in the gut lining.
• Blood Flow: It influences local blood flow to the digestive organs.
• Absorption: It plays a role in regulating the absorption of nutrients.

The ENS contains millions of neurons, organized into two main plexuses: the myenteric plexus (Auerbach's plexus), located between the longitudinal and circular muscle layers, primarily controlling motility, and the submucosal plexus (Meissner's plexus), located in the submucosa, primarily controlling secretion and absorption.