The Uterus, Endometrium, and Its Derived Stem Cells
Reproduction can be defined as the process by which an organism continues its species. The development of the normal female reproductive tract is a complex process. The paramesonephric ducts arise from the intermediate mesoderm, which are the precursors of the female reproductive organs that includes uterus, fallopian tubes, cervix, and upper vagina. The female reproductive system is designed to carry out several functions. It produces the female egg cells, the oocyte necessary for reproduction. This oocyte gets transported to the site of fertilization. Conception normally occurs in the fallopian tubes. The fertilized egg implants into the uterine wall to begin the initial stages of pregnancy. If fertilization and/or implantation do not take place, the system is designed to menstruate (the monthly shedding of the uterine lining). The female reproductive system produces female sex hormones that maintain the reproductive cycle. The fallopian tubes lead to the uterus, a muscular organ in the pelvic cavity. The inner lining, called the endometrium, thickens with blood and tissue in anticipation of a fertilized egg cell. If fertilization fails to occur, the endometrium degenerates and is shed in the process of menstruation. The endometrium begins to reach full development at puberty and thereafter exhibits remarkable changes during each menstrual cycle. It undergoes further changes before, during, and after pregnancy, during the menopause, and in old age. It undergoes unique tissue remodeling and regeneration, it remains as a dynamic tissue undergoing more than 400 cycles of regeneration, differentiation, and shedding during a woman’s lifetime. Thus, endometrium becomes the most important source of study. Based on these dynamic properties, it is ideal that stem cells of the endometrium possess an inherent and higher regenerative potential as compared to other post-natal stem cells.