Uterus is an inverted pear-shaped muscular organ of the female reproductive system. It is located in the pelvis when a woman is not pregnant. The uterus is 7,5 cm long (3 inches), 5 cm wide (2 inches), thickness is 3 cm (1.2 inches). The average weight of the uterus of an adult woman is 70 g (2.5 ounces). The uterus has 3 parts: fundus, body, cervix. The place where the cervix is connected to the body is called isthmus uteri. The cervix is linked to the vagina.
The uterus cavity is an inverted triangle with the fallopian tubes.
Cervix (cervix uteri)
The upper part of the cervix consists mainly of smooth muscle fibers. The lower part is built up of the fibrous connective tissue. The cervix produces a mucus that helps carry sperm from the vagina to the uterus, where it can fertilize an egg if the woman is ovulating. When the woman isn’t ovulating, the cervical mucus thickens and does not allow sperm enter the uterus. The discharge of the cervical mucus also depends on the level of sex hormones. During ovulation, the mucus is abundant and watery. After ovulation, it is thick and poor.
During childbirth, the cervix expands in order to allow the baby to pass through the birth canal. Once the baby is born and the placenta is expelled, the cervix begins to close.
Carcinoma sometimes develops in the cervix of the uterus. Dysplasia is a fully treatable pre-cancer condition of the cervix. If dysplasia is unnoticed and untreated, cervical cancer, which is usually caused by the human papillomavirus, begins to spread.
The body (corpus uteri)
The shape and size of the uterus depend on the level of sex hormones and how many times the woman gave birth. The cervix and the body of the newborn girl are of the same size. While the uterus body of the adult women is 2-3 times bigger than the cervix.
The uterus walls consist of the endometrium, myometrium and perimetrium membranes. The walls of the body are much thicker than those of the cervix as they protect and support the developing fetus and contain the muscles that propel the fetus out of the mother’s body during childbirth.
The cavity of the uterus is triangle-shaped and covered with mucous columnar epithelium.
Age-related changes in the uterus
Because of the disappearance of maternal estrogen after birth in the newborn girl, the uterus becomes smaller and loses the half of its weight. The cervix is 2 times longer than the uterus. At puberty, the body grows rapidly, the uterus and the cervix are of the same size. After menopause, the uterus changes, the mucous membrane becomes very thin. The glands disappear and the muscle structure decreases. These changes affect the cervix rather than the body of the uterus.
The blood supply of the uterus
The body is supplied with blood by the uterine artery. The uterine artery usually arises from the anterior division of the internal iliac artery. It travels to the uterus, crossing the ureter anteriorly, reaching the uterus by traveling in the cardinal ligament. It travels through the parametrium of the inferior broad ligament of the uterus. It basically connects with the ovarian artery.
Innervation of the uterus
You’ve got acquainted with general information about the uterus and its anatomy. In addition, its main function is child-bearing which usually lasts about 38-42 weeks. Knowing your own body is a duty of the educated person in order to understand better the natural processes.