Initial Shell Formation Research Articles

Formation of an Egg Shell

Evidence has been presented which indicates that calcification of the egg shell begins just prior to the egg entering the uterus. Initial shell formation has been shown to be crystalline in nature. Small calcium rich clusters are deposited on the outer shell membrane in the isthmus and these small clusters are the initiation sites for calcium deposition. As the deposition continues, there is a period in which the individual sites become crystalline in appearance. These deposition sites lose their individual integrity due to being covered by an amorphous calcium rich layer. When the shell is viewed cross-sectionally, the arrangement of the individual sites on the membrane can be seen as well as their transformation into the more solid outer portion of the shell.