9d Chicken Hindgut
The tissue is stained with Anna-1 in green (neuronal cell bodies) and TUJ1 in red (neuronal projections).

The cell bodies are clustered in small bundles in the myenteric plexus of the developing enteric nervous system with projections connecting these primitive ganglia along the entire length of the hindgut. The transformation between 8 and 9 days of development is dramatic. It appears that the wave of differentiation accelerates as it approaches the terminus of the hindgut. We can see that the primitive plexus of neurons is much more dense than at 8 days of development, with small clusters of neurons surrounded by many projections connecting the individual clusters within the myenteric plexus.

Note the large Nerve of Remak attached to the dorsal wall of the hindgut. This nerve is unique to birds and serves a poorly characterized regulatory function similar to the pelvic ganglia in mammals.
image by helen mcbride