Anatomy Bones and Muscles · MU Pleven

182. Autonomic plexuses and ganglia in the region of the head and neck.

Covers the enteric nervous system, often called the second brain, which lies within the gut wall from the oesophagus to the anus. It describes the myenteric and submucosal plexuses and their locations, the main gut functions they control, and their capacity to work independently of the brain and spinal cord. A stepwise account of how peristalsis moves a food bolus forward is also given, with the excitatory and inhibitory neurotransmitters involved.

Inside: 5 sections · 1 labelled picture · 15 flashcards · 3 min

Topic 181 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 5 sections, about 365 words (3 min of reading), with 15 flashcards.

In this note

  1. ENTERNIC Nerve System (Second brain)
  2. Structure & Location :
  3. Functions :
  4. Independence :
  5. Mechanism

Structure & Location :

  • The ENS consists of a network of more than 100 million nerve cells (neurons) embedded in the lining of the gastrointestinal system.
  • It extends from the esophagus to the anus and is distributed throughout the entire digestive tract.
  • The neurons of the ENS are collected into two types of ganglia:
  • Myenteric (Auerbach's) plexus: Located between the inner and outer layers of the muscularis externa. ← Controls digest. tract motility
  • Submucosal (Meissner's) plexus: Located in the submucosa 1. ← - Local secretion - Absorption - Local movement

Functions :

  • The ENS controls various aspects of gastrointestinal function, including:
  • Motor functions: Regulating muscle movements in the intestines (such as peristalsis).
  • Secretion of gastrointestinal enzymes: Coordinating the release of digestive enzymes.
  • Local blood flow: Modulating blood supply to different parts of the gut.
  • Mucosal transport: Facilitating the movement of nutrients and waste.
  • Immune and endocrine functions: Influencing immune responses and hormonal signaling 2 3.

Independence :

  • The ENS is capable of acting independently of the brain and spinal cord.
  • It is often referred to as the "second brain" due to its intricate control over gut functions.
  • Although it can operate independently, it may still receive innervation from the vagus nerve and prevertebral ganglia.
  • Notably, studies have shown that the system remains functional even with a severed vagus nerve 1.

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