Uterus and Fallopian Tube

The wall of the Uterus and Fallopian Tube is composed of three layers:

• Serosa is a thin layer of connective tissue with mesothelium
• Muscularis is organized into an inner thick circular later and outer thin longitudinal layer
• Mucosa exhibits thin longitudinal folds projective into the lumen. The folds are numerous and complex in the ampulla and become smaller in the isthmus

The four gross segments of the fallopian tube include the following:

• Infundibulum is funnel shaped, adjacent to the ovary. It opens into the peritoneal cavity. Its fringed extensions are called fimbriae and extend from the opening of the infundibulum toward the ovary
• Ampulla is the longest segment, and the site of fertilization
• Isthmus is the narrow medial segment, adjacent to the uterus
• Uterine or intramural part or interstitial part is about 1 cm and lies within the uterine wall. It opens into the cavity of the uterus

The uterus is anatomically divided into two regions:

• Body is the large upper part. The upper rounded part of the body above the attachment of the fallopian tubes is called the fundus.
• Cervix is the lower, barrel shaped part. It is separated from the body by the isthmus. The lumen is called the cervical canal and has a constricted opening at each end. The opening into the uterus is called the internus os and the opening in the vagine is called the external os.

The uterine wall is composed of three layers:

• Perimetrium is the external serous layer, which consists of mesothelium and a thin layer of loose connective tissue
• Myometrium is the thickest layer of the uterine wall. It is composed of three indistinctly defined smooth muscle layers:
• The middle layer (stratum vasculare) is the thickest layer, with muscle bundles arranged in a circular or spiral orientation. It contains numerous large blood vessels and lymph
• The inner and outer layers are oriented parallel to the long axis of the uterus
• Endometrium is the mucosal layer of the uterus. It is lined with simple columnar epithelium, which contains a mixture of secretory and ciliated cells. It undergoes cyclic changes each month with the menstrual cycle and this pattern repeats throughout the reproductive life span. The cyclic changes prepare the uterus for implantation of the embryo and subsequent fetal development. Changes correlate with maturation of the ovarian follicle and the formation of the corpus luteum. The end of the cycle is characterized by partial destruction and sloughing of the endometrium accompanied by bleeding from the endometrial vessels. The discharge of tissue and blood from the vagina (3-5 days), is called menstruation. There are 2 layers during reproductive life:
• Stratum Functionale or Functional Layer is the thick part of the endometrium that is sloughed off during menstruation
• Stratum Basale or Basal Layer is retained during menstruation and serves as a source for regeneration of the stratum functionale