the parasympathetic nervous system is the type of nervous system.
the parasympathetic nervous system is the type of nervous system.
how many types of nervous systems are there?
parasympathetic nervous system
the evolution of nervous systems dates back to the first development of nervous systems in animals (or metazoans). neurons developed as specialized electrical signaling cells in multicellular animals, adapting the mechanism of action potentials present in motile single-celled and colonial eukaryotes. simple nerve nets seen in animals like cnidaria (jellyfish) evolved first, consisted of polymodal neurons which serve a dual purpose in motor and sensory functions. cnidarians can be compared to ctenophores (comb jellyfish), which although are both jellyfish, have very different nervous systems. unlike cnidarians, ctenophores have neurons that use electrochemical signaling. this was perplexing because the phylum ctenophora was considered to be more ancient than that of porifera (sponges), which have no nervous system at all. this led to the rise of two theories which described how the early nervous system came about. one theory stated that the nervous system came about in an ancestor basal to all of these phylum, however was lost in porifera. the other theory states that the nervous system arose independently twice, one basal to cnidarians and one basal to ctenophores. bilateral animals – ventral nerve cords in invertebrates and dorsal nerve cords supported by a notochord in chordates-- evolved with a central nervous system that was around a central region, a process known as cephalization.
evolution of nervous systems
pavlov looked at the balance between excitation and inhibition and determined that there were different types of nervous systems. these observations were made about dogs, but pavlov believed that they could be generalized to humans as well. the different types of nervous systems were categorized by pavlov into strong and weak nervous systems with different sub-types under the strong type. these different types of systems were categorized based on the strength of excitation or inhibition in the system of the observed individual. those individuals with weak nervous systems were thought by pavlov "to have limited adaptive abilities," while strong nervous systems were more adaptable.
pavlov's typology