What is my ’2nd brain’?
You may have heard the term ‘2nd brain’ in reference to your gut. This is really referring to the guts own nervous system called the Enteric Nervous System(ENS) which is wrapped around the length of the intestine. This nervous system has 50-100 million nerve cells and is connected to our brain(in our head!) by nerves and the gut sends signals to the brain about conditions and goings on in the gut and the brain sends some signals back.
The ENS manages to move food along the gut as it is digested, nutrients absorbed and waste eventually eliminated. In between meals it performs housekeeping by waves of contraction that keep gut function in tip-top shape.
The ENS, or ‘2nd brain’, is part of the system of gut communication with the brain.
The other ways the gut and brain communicate is through other cell types in the gut which include:
- Immune cells that release cytokines that enter the blood stream and thus reach the brain and other systems. Immune cells are cited here as they are exposed to bacteria, viruses and other potentially harmful pathogens from the outside world
- Endocrine cells(15 types) throughout the gut which release a range of hormones into the bloodstream including gastrin, histamine, serotonin, cholecystokinin (CCK), somatostatin and glucagon-like peptides. These cells are thought to be essential regulators of digestion, gut motility, appetite, and metabolism
- The gut microbes – the guts microbes digest remaining food components and produce metabolites. These affect the nerves and immune cells of the gut and enter the bloodstream signalling the brain and other organs in a way we are only just starting to understand
In future posts we will look at these communication channels further.
Images from Vecteezy