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How does the myometrium differ from the endometrium?
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human reproductive system
Organs and structures of the male and female reproductive systems.
The myometrium and endometrium are distinct layers of the uterus that differ significantly in composition and function:
- Myometrium: This is the middle, muscular layer of the uterine wall and constitutes the bulk of the organ's mass. It is composed of densely packed, unstriped smooth muscle fibers arranged in three layers running in different directions, which provide the structural strength and contractile power of the uterus.1
- Endometrium: This is the innermost layer, serving as the glandular mucous membrane that lines the uterine cavity. Unlike the muscular myometrium, the endometrium is highly dynamic; it undergoes dramatic, hormonally induced cyclical changes throughout the menstrual cycle. It contains uterine glands and a cellular stroma that prepare the lining for the implantation of a fertilized ovum.21
While the myometrium provides the physical structure and muscular support for the uterus, the endometrium acts as the functional lining that supports potential pregnancy or is shed during menstruation.21