LECTURE XIV 



MAMMARY GLANDS 



The cow's udder is taken as a type of mammary gland. It is 

 located under the inguinal region and supported by skin, loose 

 connective tissue, and bands of white fibrous tissue which attach 

 to the fibrous tunic of the abdomen and act as ligaments to help 

 support the organ. The udder is covered by thin soft skin and 

 fine hair. 



Anatomy. — The udder is divided into two lateral halves, each 

 of which has two glands, the front and the back. Each half is 



incased in a fibrous sac of yellow elas- 

 tic tissue, thus the two lateral halves 

 are well separated by the double, con- 

 nective tissue membrane. The two 

 quarters in each half are not so sepa- 

 rated. 



The stxbstance of each gland is 

 made up of yellow glandular tissue, 

 connective tissue, nerves, blood ves- 

 sels, etc. Each gland is divided into 

 lobes, which are subdivided into 

 lobules. Each quarter of a cow's 

 udder is merely a compound gland, 

 with its connective ■ tissue framework, 

 nerves, blood and lymph vessels, etc. The gland tissue proper 

 consists of a mass of branching tubes. The terminal branches 

 end in little sac-like cavities called alveoli. These and the milk 

 ducts (tubes) are lined with epithelial cells like all other similar 

 structures. These lining cells are the factories in which the 

 casein, sugar, fat, etc., are produced, from materials brought to 

 them by the blood and lymph. 



There is one milk duct for each lobule. These small ducts 

 unite to form larger and larger ducts, and thus the milk is con- 

 veyed into the milk cistern which is located at the base of each 



72 



Fig. 33. — One Quarter and 



Teat of Cow 's Udder. 



(0. K. C.) 



C, milk cistern. Note con- 

 striction at end of teat. 

 Holes, shown in the gland 

 above, are milk ducts cut 

 across. 



