Fig. 3. Electron micrographs of the intestinal nerve in cross section. (A) Section of the nerve at the level of the seminal vesicle. There are 3025 fibre profiles, of which 1732 (57%) have diameters <0.20 µm. (B) Enlargement of the boxed area in A showing the region of very small diameter fibres. Note the surrounding boundary formed by processes of darkly staining glial cells (arrowheads).