Definition - What does Endometrium mean?
The endometrium is the innermost lining of the uterus —a pear-shaped organ with three layers: perimetrium, myometrium, and endometrium. It lines the entire uterus and merges with the lining of the cervical canal. The endometrium prepares itself each month to receive a fertilized egg. If no egg is received, the inner layer of the endometrium is shed and expelled via menstruation. If the egg is received, it implants within the endometrium leading to pregnancy.
The endometrium is also known as endometrial lining or the uterine lining.
FertilitySmarts explains Endometrium
The endometrium consists of multilayers, several cells types, blood vessels, and glands. There are three layers of the endometrium:
- Stratum basalis (the basal layer)
- Stratum spongiosum
- Stratum compactum
Together the stratum spongiosum and stratum compactum make the functional layer of the endometrium. It is this layer that undergoes changes throughout the menstrual cycle and also receives a fertilized egg for implantation. Whereas, the basal layer is more like a base that remains unchanged and from which the functional layer grows.
Being a dynamic layer, the endometrium changes with the different stages of the menstrual cycle, which is guided by a fluctuation in hormones. The endometrium also undergoes hormone-induced changes during and after pregnancy and during menopause.
It, however, maintains a constant morphology before puberty and after menopause. The number, shape, activity, and function of endometrial cells also change during the menstrual cycle and pregnancy.