262 HUMAN PHYSIOLOGY. 



The Fallopian tubes are about four inches in length, and extend 

 outward from the upper angles of the uterus, between the folds of 

 the broad ligaments, and terminate in a fringed extremity which is 

 attached by one of the fringes to the ovary. They consist of three 

 coats : 



1. The external, or peritoneal. 



2. Middle, or muscular, the fibers of which are arranged in a cir- 

 cular or longitudinal direction. 



3. Internal, or mucous, covered with ciliated epithelial cells, which 

 are always waving from the ovary toward the uterus. 



The Uterus is pyriform in shape, and may be divided into a body 

 and neck ; it measures about three inches in length and two inches 

 in breadth in the unimpregnated state. At the lower extremity of 

 the neck is the os externum ; at the junction of the neck with the 

 body is a constriction, the os internuni. The cavity of the uterus 

 is triangular in shape, the walls of the triangle being almost in 

 contact. 



The walls of the uterus are made up of several layers of non- 

 striated muscle-fibers, covered externally by peritoneum, and lined 

 internally by mucous membrane, containing numerous tubular glands, 

 and covered by ciliated epithelial cells. 



The vagina is a membranous canal, from five to six inches in 

 length, situated between the rectum and bladder. It extends obliquely 

 upward from the surface, almost to the brim of the pelvis, and em- 

 braces at its upper extremity the neck of the uterus. 



Discharge of the Ovum. As the Graafian vesicle matures it 

 increases in size, from an augmentation of its liquid contents, and 

 approaches the surface of the ovary, where it forms a projection, 

 measuring from J4 to J4 of an inch. The maturation of the vesicle 

 occurs periodically, about every twenty-eight days, and is attended 

 by the phenomena of menstruation. During this period of active 

 congestion of the reproductive organs the Graafian vesicle ruptures, 

 the ovum and liquid contents escape, and are caught by the fimbriated 

 extremity of the Fallopian tube, which has adapted itself to the pos- 

 terior surface of the ovary. The passage of the ovum through the 

 Fallopian tube into the uterus occupies from ten to fourteen days, 

 and is accomplished by muscular contraction and by the action of 

 the ciliated epithelium. 



