In the TESCAN microscopy lab we have taken a closer look at the structure of an egg, since eggs are a symbol of Easter and Spring.
The structure of the eggshell of domestic fowl is made almost entirely of calcium carbonate crystals. It is a semipermeable membrane perforated by numerous pores that allow the exchange of gases necessary for the embryo to breathe. Between the eggshell and egg white are two membranes providing efficient defense against bacterial invasion.
The first membrane surrounds the egg white and the thinner inner membrane, presented in the SEM image, is attached to the mammillary cones. The membranes are a network of fibers made partly of keratin, a protein that is also in human hair.