266 



COORDINATION AND SENSATION 



tions, called papilla. These average about one one-hun- 

 dredth of an inch in height, and one two hundred and 



fiftieth of an inch in 

 diameter. 



\ \Epidermia most 

 [J 

 .Muscte 



Arte, 



.Connective 

 tissue 



Dermi's 



Con 



Fat 



FIG. 122. Diagram of section of skin showing 

 its different structures. 



They are 

 numerous on 

 the palms of the 

 hands, the soles of 

 the feet, and the 

 under surfaces of the 

 fingers and toes. At 

 these places they are 

 larger than in other 

 parts of the body, 

 and are closely 

 grouped, forming 

 the parallel curved ridges which cover the surfaces. 

 Each papilla contains a loop of capillaries and a small 

 nerve, and many of them are crowned with touch 

 corpuscles (page 342). 



The Epidermis is much thinner than the dermis. It is 

 made up of several layers of cells which are flat and scale- 

 like at the surface, but are rounded in form where the 

 epidermis joins the dermis. The epidermis has the ap- 

 pearance of being moulded onto the dermis, filling up the 

 depressions between the papillae and having correspond- 

 ing irregularities (Fig. 121). No blood vessels are found 

 in the epidermis, its nourishment being derived from the 

 lymph which reaches it from the dermis. . Only the part 

 next to the dermis is made up of living cells. These are 

 active, however, in the formation of new cells, which take 

 the place of those that are worn off at the surface. Some 

 of the cells belonging to the inner layer of epidermis con- 

 tain pigment granules, which give the skin its color (Fig. 



