Figure 5: Electron micrograph of a twenty day rat’s skin showing: (a) Collagen fibres longitudinally and cross-sectioned (C), fibroblast (F), skeletal muscle (S) and its nucleus (Ncl) (X 4000). (b) Collagen fibres (C) and myelinated derm nerves (N) (X 2500). (c) Collagen fibres (C) and normal dermal mast cell (M) filled with granules (g) (X 4000).