THE SALIVARY GLANDS 



The glands of the neck should be studied first, because 

 they or their ducts are likely to be injured during the dis- 

 section of the blood vessels of this region. Cautiously 

 remove the skin from the head and neck, taking care to 

 avoid injuring the underlying muscles, blood vessels, and 

 glands. Removal of the subcutaneous connective tissue on 

 the ventral and lateral surfaces of the neck will now reveal 

 the glands. These are of three types, salivary, lymph, and 

 lacrimal. 



The salivary glands secrete the saliva, which is mixed 

 with the food in the mouth during mastication. Look for 

 two of them in the rat, the parotid and the suh maxillary 

 glands. The parotid is the rather loosely organized, elon- 

 gated, mass extending from the base of the external ear 

 along the side of the neck to the ventral surface of it. Find 

 and trace the parotid duct (Stenson's duct) which trans- 

 ports the salivary secretion from the gland to the mouth 

 cavity. The duct is formed by the union of several tribu- 

 taries from different parts of the gland, traverses the lat- 

 eral surface of the jaw muscle (masseter), then turns 

 inward to the mouth cavity. The duct should not be con- 

 fused with the nerves which cross the surface of the muscle 

 in this region. Immediately anterior to the dorsal portion 

 of the parotid is the extra-orbital portion of the lacrimal, 

 or tear, gland. Locate its duct and trace it to the eye. 

 The submaxillary glands are the large elongated pair on 

 the ventral surface of the neck. The median faces of these 

 glands are in contact with one another, in the sagittal plane 



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