A scanning and transmission electron microscopic study of the membranes of chicken egg

Abstract

Questions regarding the structure of the inner and outer shell membranes of the chicken egg were addressed in this study by correlating observations from light microscopy and scanning and transmission electron microscopy. The egg membrane had a limiting membrane, which measured .9 to .15 pn in thickness and appeared to be a continuous and an impervious layer, but the shell membrane did not. Under the SEM, each membrane was seen to be made up of severa1 fibre layers. In the tear preparations viewed under the SEM two layers were observed in the egg membranes and three to five layers in the shell membrane, with an apparent plane of cleavage between each layer. Each fibre was made up of a central core and an outer mantle layers. The central core was perforated by channels which measured .O8 to 1.1 1 pn in diameter and ran longitudinally along the length of the fibre. Between the mantle layer and the fibre core was a gap or cleft measuring between .O3 to .07pn. The diameter of the fibres of the inner layer of the egg membrane ranged between .O8 to .64pn, whereas those of the outer layer of the same membrane ranged from .O5 to 1.11 p.m. Fibres in the shell membrane ranged from . l l to 4.14 pm diameter.