The Female Reproductive System - Accessory Ducts

Accessory ducts:

The fallopian tubes (uterine tubes or oviducts), uterus, and vagina constitute the female accessory organs.

1) Oviduct (fallopian tube or Uterine tubes):

• Each ovary is positioned in front of a funnel-shaped hole in the uterus called the oviduct.
• Each fallopian tube extends from the periphery of each ovary to the uterus.
• Each oviduct is a muscular tube that is roughly 10-12 cm long.
• The oviducts are also referred to as the uterine tubes or the fallopian tube.
• It has ciliated epithelium lining its lumen.
• The embryo's mullarian duct gives rise to oviducts.
• It transports the egg from the ovary to the uterus and provides the necessary conditions for fertilization.
• It is supported by the mesosalpinx, a double fold of the peritoneum.
• The oviduct is divided into four regions:
  i) Infundibulum:  The proximal part of the fallopian tube bears a funnel-shaped infundibulum. The edges of the infundibulum have many motile, finger like projections called fimbriae which help in the collection of the ovum after ovulation. It enters the body cavity through an orifice known as the ostium. The latter is located near the ovary in order to accept the egg discharged by the ovary. Cilia on the fimbriae beat toward the ostium, directing the egg into the infundibulum.
  ii) Ampulla: The ampulla is the long, wide, thin-walled, tortuous main portion of the fallopian tube located close to the infundibulum.
  iii) Isthmus: The last part of the oviduct is the isthmus which is short and thick-walled connecting the ampulla and infundibulum to the uterus.

2) Uterus:

• The uterus is also narrow, passing through the uterine wall and communicating with the uterine cavity.
• The oviduct is frequently ciliated in its ampullary part.
• Peristaltic and ciliary activity propels eggs along the oviduct.
• The oviducts open into the uterus's upper corners, known as the cornua (plural-conru).
• The ovaries and oviducts are both functioning in most vertebrates.
• The right ovary and oviduct are atrophied in birds (Degenerated). Because birds are nonmammalian, they lack mammalian sex organs and characteristics such as the uterus, external genitalia, and mammary glands. 
• The wall of the uterus has three layers of tissues.
  i) Perimetrium (serosa or adventitia): It is the outermost thin layer of the visceral peritoneum.
  ii)  Myometrium (Muscle-layer): The middle layer of the oviduct is made up of unstripped-muscle. In the uterus, thick smooth, muscle bundles are found, these are called the myometrium. 
  iii) Mucous membrane: It is the innermost layer. The mucosa consists of simple columnar epithelium. The epithelium contains both ciliated cells and secretory cells. The secretory cells produce a viscous liquid film that provides nutrition and protects the ovum. The mucosa of the uterus is called endometrium (glandular layer), it contains simple - branched tubular glands, many fibroblasts, and blood vessels. In the uterus, the embryo is attached to the endometrium. The endometrium undergoes cyclical changes during the menstrual cycle while the myometrium exhibits strong contraction during delivery of the body.

3) Vagina:

• Vagina is a large fibromuscular tube that extends from the cervix to the exterior.
• It is the female organ of copulation.