Innervation, Especially, Sensory Innervation of Urethra in the Distal Part of Pig Penis

Abstract

The nerves penetrating into the mucous membrane of pars cavernosa urethrae in pig comprise a large number of thin medullated fibres and a small number of thick medullated fibres, including also a few vegetative nerve fibres.
The termination of vegetative fibres is represented by STÖHR's terminalreticulum also in pig urethra.
The sensory nerve fibres and their terminations in pig urethra are far below in evolution in comparison with those in human urethra. The genital nerve bodies type III can be mentioned first as the sensory endings not rarely found in pig urethra. They originate from thick medullated fibres and are formed in the periphery of the lamina propria mucosae in main.
Branched terminations are also not rare and these are composed of 2 or 3 branches only. Unbranched terminations are the most numerous sensory terminations in the urethra. These two types of terminations come from the thin medullated fibres in general, and only rarely from thick fibres.
Intraepithelial fibres are in inferior stage of development and are represented by the unbranched type in all cases. These are derived mainly from thin medullated fibres but sometimes from thick medullated fibres.