ZOOL342 Lecture Notes - Lecture 1: Thoracic Ganglia, Posterior Grey Column, Symmetry In Biology
Document Summary
Structure: throughout evolution the nervous system changed. Earlier there was only a nerve net that could pass information through the body. Then, bilateral symmetry evolved the nervous system cut down half is more or else the same. This allows to move the head and sense environment in front of them: then there is hierarchal organization information moves upwards from cells to multiple cells or other way around, these are generalized trends through evolution. Nd axons of the neurons that run up and down the length of the organism. Commissure is regions where axons are projected laterally, and neuropile is where all the synaptic connections occur and all the cells talk to each other in this region. Depending on the invertebrate they have different amount of ganglia. like cockroach has more thoracic ganglia. These axons project all the way up to the thoracic ganglia and send synapse to the motor neurons. designed for rapid information transfer.