2030 



Hf.MAN ANATOMY. 



Excretory duct 



At fn mall and much like the terminal compartments of the gland and 



with a thin >t rat um of longitudinally disposed involuntary muscle, upon which 

 of cuboid epithelial cells. The latter give place to cells of col- 

 umnar type within the lactiferous 



' ~ ' 2 - ducts that are formed by the 



junction of the smaller canals. 

 On approaching the base of the 

 nipple, beneath the areola, each 

 milk-duct presents a spindle-form 

 enlargement or ampulla (sinus 

 lactiferus), from 10-12 mm. long 

 and about half as wide, that 

 serves as a temporary reservoir 

 for the secretion of the gland. 

 Beyond the ampulla the duct 

 narrows to a calibre of little over 

 2 mm., passes into the nipple, 

 and ends, after traversing the lat- 

 ter parallel with the other ducts, 

 in a minute orifice from .5-. 7 

 mm. in diameter, at the summit 

 of the papilla. On gaining the 

 last-named point, the lining epi- 

 thelium of the duct assumes the 

 stratified squamous type of the 

 adjacent epidermis. Embedded 

 within the delicate but more or 



Involuntary 

 muscle 



Section of mammary gland before lactation. X 170. 



mark 



' 



. . ,, ,.,, aycr> aces almos( en Cr c, 



e the skin is 



FIG. 



1713. 



during lactation and 



for protection while nursing. 



alent over 



the nipple, but lar^e and modj- 

 ti-d in the vicinity ol the periph- 



1.1." Thr Mil face,, f 



tin- latter is modelled. es|,e< ially 



IU the dose of |.l 



!'-vation> that 

 indi.ate tin- |.< ,,iti, ,ns of th. 



Hi.- lati. 



rudimentary 



t"n i , nun. 

 id in 



"IK tin. with that 

 <-f tin- mammary glands. Their 



on th 



Milk. I he fully fstali 



!ll( - mamnuiv dim! n,. r 



sus,K.-nded i,, \ \ J, t a,^'" 1 " 11 " 11 "^'"emulsion, the fatty milk- 

 111 llllt '""" 1'luish to yellowish v MS, and waterv plasma, the variations 



-depending upon the amount of fat. The 



Section 



distended 





