They are, however, less excitable than are the nerve cells which innervate them.
In the Metanemertini, where the longitudinal stems lie inside the muscular body-wall, definite and metamerically placed nerve branches spring from them and divide dichotomously in the different tissues they innervate.
The nervous system is represented by an oesophageal collar and a suboesophageal ganglion, whence paired nerves pass outwards to innervate the anterior extremity and backwards towards its posterior end.
Poliomyelitis causes an overall loss of motor units; therefore, the remaining units must innervate many more muscle fibers than they did originally.
Sensory nerves supply or innervate particular regions of the body.