i believe you're talkin about the cervix.
The wall of the uterus is made up of three main layers. The inner most layer is the Endometrium. The middle layer is the Myometrium and the outer most layer is the Perimetrium, or adventitia or serosa.
A woman's uterus is a pear-shaped organ located in the pelvis. It is made up of three layers: the outer layer called the perimetrium, the middle layer called the myometrium, and the inner layer called the endometrium. The uterus is where a fertilized egg implants and grows during pregnancy.
The lower part of the mantle is called the mesosphere.
Perimetriumperimetrium
outer core
The outer cervical os is the opening in the uterine cervix (the neck of the uterus) closer to the vagina. Its counterpart is the interior cervical os, which is opening in the cervix closer to the uterus.
The strong lower part of the mantle between the asthenosphere and the outer core is called the lower mantle. The layer of the atmosphere between the stratosphere and the thermosphere is called the mesosphere.
When the embryo reaches the uterus, it is a hollow ball of about 100 cells called a blastocyst. The blastocyst is made up of an outer layer of cells that will develop into the placenta and an inner cell mass that will develop into the embryo.
The perimetrium is essentially a coat to the uterus. It is the outer serosa layer of the uterus and it is part of the visceral peritoneum membrane.
The Outer Limits - 1995 Straight and Narrow 2-8 was released on: USA: 23 February 1996
The uterus is divided into three main parts: the fundus (upper portion), the body (middle portion), and the cervix (lower portion). The cervix further consists of the inner cervical canal, which connects the uterus to the vagina, and the outer cervical os, which is the opening of the canal into the vagina.
The perimetrium is the outer layer of the uterus in the female reproductive system and its function is primarily to provide support to the uterus.