Microanatomy - The cellular anatomy of invertebrate ganglia can be readily examined in whole mounts, in situ, using Methylene blue staining in freshly dissected preparations. A detailed protocol for the use of Methylene blue is attached. The goal of this laboratory is to compare and contrast the ladderlike chain organization of the central nervous system in distantly related animal groups. Your goal is to identify analogous structures in the different groups. Polychaetes - Polychaetes have a relatively primitive nervous system, characterized by diffusely organized ganglia.
Serial homology is the rule.
Identify the supra and subesophageal ganglia and circumesophageal ganglia. How many nerves ramify from each ganglia. Can you recognize any central neurons in methylene blue preps. In the crayfish, Identify the supra and subesophageal ganglia, the five thoracic ganglia and the 6 abdominal ganglia. Several visceral ganglia occur including the commissural ganglia on the circumesophageal ganglia, the stomatogastric ganglia in the lumen of the dorsal median artery and the cardiac ganglia in the lumen of the heart.