Endometrium is a innermost glandular layer of uterus and myometrium is a middle muscular layer of the uterus.
Function of the endometrium is to maintain the patency of the uterine cavity and it create an optimal environment for the implantation of blastocyst by growing into a thick, blood-vessel rich glandular layer.
The myometrium has a very important function during pregnancy where it stretches to allow for the harbouring of pregnancy by increasing in size and contracts in coordinated fashion during the process of labour.
After the delivery myometrium contracts to expel the placenta and reduce blood loss.