Egg Sandwich

Posted by Kathryn Trout on May 7, 2005

Q: I know this sounds like a silly question..so dont laugh...but how exactly does an eggshell form inside its mother.

A: Kathryn: without getting too deep into the physiology of the subject, suffice it to say that after an uncalcified egg is formed in the bird's uterus it enters the oviduct. At this point it is yolk and albumen. The yolk is the yellow part of the egg and it is surrounded by the albumen, or white part of the egg.

The shell membranes are then deposited on the outside of the albumen in the

isthmus region of the oviduct.

Calcification begins at the junction of the

isthmus and the shell gland in the tubular shell gland region of the

isthmus. Hen's eggs spend about 15 to 20 minutes in the region during

formation.

Jim Berry ( May 10, 2005)

Filed under: Birds