[Evolution of encapsulated sensory nerve endings in the hairless part of the lips of mammals].
The simple cylindrical end-bulb is the unique type of encapsulated receptors of the hairless part of the lips in Rodentia, Carnivora and Ruminantia. For the first time, more complex sensory structures have been established in Apes. Having regard to the terminal nerve arborization, three types of sensory corpuscles can be differentiated. The 1st one is the transitional type between the simple end bulb and more complicated receptors in Primates. The terminal nerve fibres are very thick and simply convoluted. The 2nd type comprises thick nerve coils surrounded by intermingled thin nerve branches. The 3rd type contains mainly thin nerve branches which form twisty configuration. Meissner's corpuscles have been proved only in Primates - Apes and Man. The results give strong evidence that the complex structure of apes sensory corpuscles is an quantitative evolutionary improvement. The man encapsulated receptors do not differ substantially from apes corpuscles. In other words, the man evolution does not present so significant evolutionary leap as the apes do.
D000818:Animals; D005075:Biological Evolution; D002417:Cattle; D006168:Guinea Pigs; D006801:Humans; D008046:Lip / Q000294:innervation*; D008253:Macaca mulatta; D008322:Mammals / Q000033:anatomy & histology*; D051379:Mice; D009412:Nerve Fibers / Q000648:ultrastructure; D011817:Rabbits; D051381:Rats; D011984:Sensory Receptor Cells / Q000033:anatomy & histology*; D013552:Swine
Die Evolution der eingekapselten sensiblen Nervenendapparate in dem unbehaarten Lippenteil der Säugetiere.