The Uterus . Also called the womb or womb, it is the organ of pregnancy and the largest organ of the female reproductive system in most mammals, including humans. It is a hollow, pear-shaped, extraperitoneal, muscular organ located in the woman’s greater pelvis , which when it adopts the position in anteversion rests on the urethral bladder in front, with the rectum behind. Located between the vagina and the fallopian tubes , it houses the blastula, which implants in the endometrium, starting gestation, which in humans lasts about 280 days.
• Simple: Found in humans and other primates.
Double: Characteristic of rodents (mice, rats and hamsters), marsupials and lagomorpha (rabbits and hares).


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  • 1 Anatomy of the uterus in women
  • 2 Regions
  • 3 Layers
  • 4 Location, form and function
  • 5 The three layers of the uterine wall
  • 6 The uterus during pregnancy
  • 7 Sources

Anatomy of the uterus in women

The uterus consists of a body, a base or bottom, a neck or cervix, and a mouth. It is suspended in the pelvis and is positioned with the base facing up and forward, and the neck facing slightly back. It is connected to the vagina through the cervix; On each of its sides there is an ovary that produces ovules or eggs that reach it through the fallopian tubes. When there is no pregnancy, the uterus is about 7.6 cm long, 5 cm wide, and 2.5 cm thick.
During gestation, the fertilized egg implants in the uterine lining, where it grows to maturity. The walls of the uterus are elastic and stretch during pregnancy to house the growing fetus. Although the uterus is a muscular organ, it has a lining of soft glandular material that becomes denser during ovulation, at which point it is ready to receive a fertilized egg. If fertilization does not occur, this lining is expelled during menstruation.


The uterus is made up of two anatomically and functionally distinct areas that are:

  • The uterine body, to which the fallopian tubes are attached at the sides. It is separated from the cervix or cervix by the uterine isthmus.
  • The cervix or cervixcommunicates with the isthmus at its upper end, while the lower end ends up protruding in the upper part of the vagina, which is called portio or snout of tench. The external cervical opening through which the cervix empties into the vagina takes a different shape depending on parity, an event that can be visualized by colposcopy or direct cervical examination.



The uterus is partially covered by peritoneum in the uterine fundus, in its most posterior part. On the sides it presents round ligaments and on the front to the bladder. The wall of the uterus presents to the section three layers of cells that are from the outside to the inside:

  • Serosa or Perimetrium, corresponds to the peritoneum in the posterior superior part, and to the loose tissue that extends along the sides of the uterus in what is called the parametrium.
  • Myometrium, consisting mainly of smooth muscle tissue. The innermost layer of the myometrium is a transition zone that thickens in adenomyosis.
  • Endometrium, is a specialized mucous layer that is renewed in each menstrual cycle if there is no fertilization.

It is the portion shed during the menstruation or period throughout the fertile years of the woman. In other mammals the menstrual cycle can be separated from each other for several days and up to six months.

Location, form and function

The uterus (Lat. Womb) is a muscular organ that is located between and slightly below the ovaries, approximately in the center of the lower abdomen. The shape of the uterus, which is almost 3 inches (7 cm.) In length, resembles that of a small inverted pear. The fallopian tubes enter the uterus on both sides near the top. The wide upper part, known as the body of the uterus, is usually inclined over the dome of the urinary bladder, and is separated from the narrow lower part by a thin contraction. This lower part is called the cervix or cervix, and it ends in the deep part of the vagina. The cervix contains a small opening where sperm cells can travel from the vagina to the uterus. However, except for a certain period during ovulation,

The three layers of the uterine wall

The thick walls of the uterus are made up of three layers:
1. The outer layer is called the perimeter.
2.The middle or muscular layer called the myometrium.
3.The interior is called the endometrium.
This endometrium consists of specialized tissue that thickens every month as the uterus prepares for the possible implantation of a fertilized egg. If no implantation occurs, the endometrium breaks down and is discharged through the cervix and vagina during menstruation.

The uterus during pregnancy

In case of pregnancy, the uterus expands with the growing fetus. The extraordinary muscular structure of the myometrium not only takes into account the capacity for such expansion, but also provides the necessary pressure during labor when the fetus is finally expelled. The uterine muscles also contract during orgasm.


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