The endometrium is the mucous membrane covering the cavity inside the womb. During a woman's
productive life it constantly changes.
All the changes occuring in the endometrium during the menstrual cycle are described
The next drawing summarises all the changes occuring in the endometrium during the menstrual cycle. It also
relates these changes to whats happening in the ovary during the reproductive cycle
The following video clip shows the endomtrium (as seen during hysteroscopy examination) after ovulation , about five days
before the onset of menstruation.
For those of you who wanted a more detailed description of the endometrium, here it is.
The endometrium is a complex organ. It consists of a surface epithelium ( columnar
epithelium), glands and blood vessels.
Here is a short explanation of a gland. The surface epithelium bends inward
to form indentations. The cells at the base
of these indentations, usually change and becomes cells with special secretory functions.
In the endometrium these cells secrete large amounts of proteins.
The next drawing shows the endometrium immediately after the menstruation stopped. The
endometrium is thin and the glands are wide and shallow with very little glandular activity.
Remember this layer covers the whole cavity inside the uterus.
Only one of million glands are shown here.
The endometrium growths thicker due to oestrogen stimulation. It continues to
grow until ovulation occurs approximately two weeks after the menstruation began.
The next drawing shows the endometrium just before ovulation is going to
take place. The scientific name for this stage is " the follicular phase".The
glands are deeper and the cells at the base are changing into glandular cells
(cells with secretory functions)
Following ovulation, a structure called the corpus luteum, develops
in the ovary. The corpus luteum secretes oestrogen and progesterone. Progesterone
increases the glandular activity of the glands, blood supply increases and arteries
become tortuous (spiral arteries) The cavities of the glands are filled with proteins.
The scientific name for this stage is " Secretory endometrium".
The next drawing shows the endometrium prior to menstruation during the secretory phase.
The spriral areteries are shown. There is secretions present in the lumen of the
The next drawing shows the endometrium at the onset of menstruation.
The spiral arteries begin ti disintegrate and blood is leaking into the endometrium
The next drawing shows the menstruating endometrium.