866 



GENERATION. 



submucous areolar tissue, the membrane being applied directly to the uterine walls. It is 

 covered by a single layer of cylindrical epithelial cells with delicate cilia, the movements 

 of which are from without inward, toward the openings of the Fallopian tubes. Ex- 

 amination of the surface of the membrane 

 with a low magnifying power shows the 

 openings of numerous tubular glands. 

 These glands are usually simple, some- 

 times branched, dividing, about midway 

 between the opening and the lower ex- 

 tremity, into two and, very rarely, into 

 three secondary tubules. Their course is 

 generally tortuous, so that their length 

 frequently exceeds the thickness of the 

 mucous membrane. The openings of these 

 tubes are about F |^ of an inch in diameter. 

 The uterine tubes are of considerable 

 physiological interest and have been the 

 subject of much discussion. Their secre- 

 tion, which forms a thin layer of mucus 

 on the surface of the membrane in health, 

 is grayish, viscid, and feebly alkaline. The 

 tubes themselves have exceedingly thin, 

 structureless walls, and are lined with 

 cylindrical ciliated epithelial cells. 



The changes which the mucous mem- 

 brane of the body of the uterus undergoes 

 during menstruation are remarkable. Un- 

 der ordinary conditions, its thickness is 

 but it measures, during the menstrual period, from to of 



276. Inner layer of muscular fibres of the uterus. 



(Liegeois.) 



a, a, rin^s around the openings of the Fallopian tubes ; b, &, 

 circular fibres of the cervix. 



of an inch 



from 3*5- to 

 an inch. 



In the cervix, the mucous membrane is paler, firmer, and thicker than the mem- 

 brane of the body of the uterus, and between these two surfaces, there is a distinct 

 line of demarkation. It is here more loosely attached to the subjacent tissue in the 

 cervix, and the anterior and posterior surfaces of the neck present an appearance of 

 folds radiating from the median line, forming what has been called the arbor vita3 uteri, 

 or plicaa palmatse. These so-called folds are supposed by some anatomists to be formed 

 by rows of large, papillary elevations of the membrane. Throughout the entire cervical 

 membrane, are numerous mucous glands, and, in addition, in the lower portion, are a 

 few rounded, semitransparent, closed follicles, called the ovules of Naboth, which are 

 probably cystic enlargements of obstructed follicles. The upper half of the cervical 

 membrane is smooth, but the lower half presents numerous villi. The epithelium of 

 the cervix presents great variations in its character in different individuals. Before the 

 time of puberty, the entire membrane of the cervix is covered with ciliated epithelium. 

 After puberty, however, the epithelium of the lower portion changes its character, and 

 we have cylindrical cells above, with squamous cells in the inferior portion. The latter 

 extend upward in the neck to a variable distance. 



The blood-vessels of the uterus are very large and present certain important peculi- 

 arities in their arrangement. The uterine arteries pass between the layers of the broad 

 ligament to the neck, and then ascend by the sides of the uterus, presenting an exceed- 

 ingly rich plexus of convoluted vessels, anastomosing above with branches from the 

 ovarian arteries, sending branches over the body of the uterus, and Bnally penetrating 

 the organ, to be distributed mainly in the middle layer of muscular fibres. In their 

 course, these vessels present the convoluted arrangement characteristic of erectile tissue 



