The ovary consists of two parts, the central part or medulla, composed of connective tissue, nerves, blood and lymph vessels, and the cortex, in which are embedded the vesicular Graafian follicles containing the ova. At birth each ovary contains upwards of 50,000 of these ova, which are the germ cells concerned with reproduction and the process of menstruation.
These ovarian glands perform two vital functions, for in addition to their prime function of producing and maturing the germinal cell of the female, they provide an internal secretion which exercises an immeasurably important, though imperfectly understood, influence upon the general well-being of the entire organism.
Fig. 12.—Sagittal section of female generative tract. Drawn by Max Brodel. (Used by permission of A. J. Nystrom & Co., Chicago.)
The vagina is an elastic, muscular sheath or tube, about four inches long, lying behind the bladder and urethra and in front of the rectum. It leads interiorly up and backward from the vulva to the cervix, which it encases for about half an inch. The space between the outer surface of the cervix that extends into the vagina, and the surrounding vaginal walls, is called the fornix. For convenience of description, this is divided into four sections or fornices: the anterior, posterior and lateral fornices.
Between the posterior fornix and the rectum a fold of the peritoneum drops down and forms a blind pouch known as Douglas’ cul-de-sac. At this point the delicate peritoneum is separated from the vagina by only a thin, easily punctured, muscular wall. This is a fact of grave surgical significance, for unless instruments and nozzles introduced into the vagina are very gently and skillfully directed, they may easily pierce this thin partition. Septic material may thus gain entrance to the peritoneal cavity and peritonitis result.
The bore of the vaginal canal ordinarily permits of the introduction of one or two fingers. It is somewhat flattened from before backward, and on cross section resembles the letter H. During labor this canal becomes enormously dilated, being then four or five inches in diameter, and permits the passage of the full term child.
The vagina is lined with a thick, heavy, mucous membrane which normally lies in transverse folds or corrugations called rugæ. These folds are obliterated and the lining stretched into a smooth surface as the canal dilates during labor.
Attention must be drawn to the fact that the vagina, cervix, uterus and tubes form a continuous canal from the vulva to the easily infected peritoneum, a fact which makes absolute surgical cleanliness in obstetrics virtually a matter of life or death to the patient.
This muscular tube is lined throughout its entire length with mucous membrane, which, though continuous, changes somewhat in character along its course. The epithelial cells of the lining of the tubes and body of the uterus have hair-like projections, cilia, which maintain a constant waving motion from above downward. The effect of this sweeping current is to carry down toward the outlet any object or secretion which may be upon the surface of the lining of the tubes or uterine cavity. The unfertilized ovum is thus swept down to meet the germ cell of the male and become fertilized.