440 



THE FEMALE REPRODUCTIVE ORGANS 



The ducts of the mammary gland are lined by either a single 

 or double row of low columnar cells. They possess a relatively 

 broad lumen. Their membrana propria is supported by a thin 



connective tissue wall, containing 

 both circular and longitudinal elas- 

 tic fibres but no muscle (Kolliker,* 

 Schaferf). The elastic fibres of 

 the smaller ducts are poorly devel- 

 oped, but in suitable specimens the 

 longitudinal fibres are readily seen 

 even in very small branches. Be- 

 yond the lactiferous sinus the duct 

 epithelium changes to a stratified 

 squamous variety which is continu- 

 ous with that of the cutaneous sur- 

 face- of the nipple. 



The glandular lobules are firmly 

 united by strong septa derived from 

 the dense areolar tissue in which 

 they are embedded. In the deeper 

 parts of the gland occasional lobules 



of fat are found in this tissue. Within the nipple and beneath 

 the adjacent portions of the areola, smooth muscle fibres are also 

 found. These are arranged in circular bundles at the base of the 

 nipple, with longitudinal fibres within its substance which, at the 

 base of the mammilla, diverge in radiating bundles into the sub- 

 cutaneous tissue of the areolar zone. Contraction of these fibres 

 elevates and hardens the nipple, thus stimulating the action of 

 the erectile tissues. 



Embedded in the subcutaneous tissue of the areola are also a 

 number of small accessory lactiferous glands known as the Glands 

 of Montgomery (Areolar Glands of Duval). 



THE RESTING GLAND. With the cessation of lactation the 

 glandular alveoli undergo a rapid atrophy, and are replaced by 

 connective tissue derived from the interlobular stroma. The 

 ducts contract and the epithelium piles up to form a two-rowed, 

 or even thicker, layer. The alveoli are reduced to mere buds 

 from the terminal ducts, and their lumen is almost obliterated ; 

 their epithelium is similarly massed into a double layer of small 

 cells. The lobules are reduced in size and consist only of a few 



FIG. 354. MODEL OF A RECONSTRUC- 

 TION OF AN INTRALOBULAR DUCT 

 AND ITS ACINI FROM THE ACTIVE 

 MAMMARY GLAND OF A WOMAN. 



x 200. (After Maziarski.) 



* Handbuch, iii, 591. 



f Quain's Anat., iii, pt. iv. 



