396 



THE SKIN AND ITS APPENDAGES. 



D. THE GLANDS OF THE SKIN. 



The glands in the skin are of two kinds sweat-glands and 

 sebaceous glands. In this connection we may also consider the 

 mammary glands, which may be regarded as a modified skin gland. 



I. The Sweat-glands. The sweat-glands, or sudoriparous 



Fig. 319. A, B, Two views of a model of the coiled portion of a sweat-gland 

 from the plantar region of a man, reconstructed by Bern's wax-plate method ; X Io 

 ( Huber-Adamson). 



glands, are distributed throughout the entire skin, but are especially 

 numerous in certain regions as, for instance, the axilla, palm of 

 the hand, and sole of the foot. They lie imbedded either in the 

 adipose tissue of the true skin, or still 'deeper in the subcutaneous 

 connective tissue. 



The sweat-glands are simple tubular in type, and their secreting 



portion is coiled ; hence 

 the name coil-glands. 

 The coiled portion of 

 these glands measures 

 0.3 to 0.4 mm. The 

 excretory duct is nearly 

 straight in its course 

 through the corium. 

 From here on its course 

 is spiral, and it should 

 be borne in mind that in 

 its passage through the 

 epidermis it has no other 

 wall than the epidermal 

 cells of the various lay- 

 ers through which it 

 passes, although these 

 cells are arranged con- 

 centrically around the lumen of the duct. The duct takes part in 

 the formation of the coiled portion of the gland, forming about one- 

 fourth of the length of the tubule which takes part in the formation 



Basement 

 membrane. 



Nonstriated 

 muscle-cell. 



Gland-cell. 



Fig- 3 20 - Cross - section of tubule of coiled 

 portion of sweat-gland of human axilla. Fixation 

 with sublimate ; X . 



