THE SKIN 



scalp, the cells stick together and form flakes called 

 dandruff. 



5. Organs in the Dermis. The tough, flexible sheet 

 called the dermis is called by what other name ? Lodged 

 among its fibers and supported by them (Fig. 2) are 

 (i) a fine network of blood vessels; (2) a fine network 

 of nerves; (3) several 



million sweat glands; 

 (4) a great number of 

 oil glands. Suppose 

 you were to stick a 

 pin into the true skin. 

 You would find evi- 

 dence that you had 

 wounded which two 

 of these possessions 

 of the true skin ? Are 

 they so numerous that 

 you could penetrate 

 the skin anywhere 



without Striking FIG. 4. Coiled End of a Sweat Gland, Epidermis 



them? You learned 



that the dermis is 



composed chiefly of 



fibers, and that the epidermis is composed of cells. 



cells are very simple and are called epithelial cells. 



6. The Sweat Glands, or perspiratory glands (Figs, i 

 and 4), are little tubes, lined with epithelial cells, which 

 pass through the epidermis and down into the dermis. 

 The tube is coiled into a ball in the true skin, where it is 

 surrounded by a network of capillaries. Its course through 

 the epidermis is spiral like the turns of a corkscrew. Its 

 opening on the surface is called a pore. The coiled part 

 is supplied with nerves which stimulate the cells to secrete 

 the perspiration. The cells obtain their supply of material 



not shown. 



, the coil; b, the duct; c, network of capillaries, inside 

 of which the gland lies. Does the sweat gland lie in 

 the skin or beneath the skin? (See Fig. i.) 



These 



