Anatomy of the Women Reproductive System
The uterus is the main female reproductive organ that holds the baby during pregnancy. In the absence of pregnancy, menstruation originates from the uterus every month what is generally called periods.
Non pregnant uterine size is approximately 3 inches long and weighs about one one third of a pound. Uterus has a shape like pear.
Two anatomic regions separate in functions make up the uterine body, the Cervix is the mouth opening to the vagina, and the corpus holding the fetus for nine months.
The corpus is composed of the fundus and the collus (Isthmus) which is the lower uterine segment
The cervix is a tight cylindrical passage composed if very dense collagen fibers. The length and tightness of cervix differs by age and parity from one women to another. The upper and lower ends of the again differs in specific ways; while the lower opening to vagina is tighter in nulliparous , it is clinically different in multiparous ; the upper end opening up to the cavity is typically tighter and acutely angulated usually anteriourly. The variation of the anatomy and injuries to the cervical body is associated with series of medical conditions from cervical incompetance causing premature birth to severe dysmenorhea related with endometriosis.
The corpus is the body of the uterus which grows during pregnancy to carry a fetus.
Extending from the top of the uterus on either side are the fallopian tubes (oviducts); these tubes are continuous with the uterine cavity and allow the passage of an egg (ova) from the ovaries to the uterus where the egg may implant if fertilized
The thick wall of the uterus is formed of three layers:
The uterine mucosa (endometrium) is the innermost layer that lines the cavity of the uterus (inner walls), nourishes the fetus during pregnancy.
Throughout the menstrual cycle, the endometrium grows progressively thicker with a rich blood supply to prepare the uterus for potential implantation of an embryo.
In a woman who is not pregnant, a portion of this layer is shed each month during menstruation.
The walls of the uterus (myometrium)is the middle and thickest layer of the uterus and is composed of involuntary (smooth) muscle.
The myometrium contracts during menstruation to help expel the sloughed endometrial lining and during childbirth to allows a woman to give birth.
The outermost layer, or serosa, is a thin fibrous layer contiguous with extrauterine connective tissue structures such as ligaments that give mechanical support to the uterus within the pelvic cavity.