SKIN HAIR 95 



APPENDAGES OF THE SKIN 



The appendages of the skin are the hairs, sebaceous glands, 



sudoriferous glands, and the nails. 



t 



THE HAIR 



A hair, consisting of a root and shaft, is constructed from 

 elongated, often pigmented cells, which are cemented together 

 and overlapped with cell -plates, which form the cuticle. The 

 central part of medullated hairs is composed of cubical cells and 

 occasional minute air -bubbles. 



The root penetrates the stratum corneum and (appearing to 

 have pushed the rete mucosum before it) passes through the true 

 skin and terminates in a bulb usually in the subcutaneous tissue, 

 where it rests upon a papilla composed of an extremely delicate 

 plexus of blood -capillaries. 



The Hair- Follicle. The root of the hair, in its passage to the 

 papilla, is invested with sheaths derived from the skin. The hair, 



E 



FIG. 68. TRANSVERSE SECTION OF HAIR AND HAIR-FOLLICLE. 

 PARTLY DIAGRAMMATIC. 



A. Medulla of hair. 



B. Cortex of same. 



C. Root-sheath. 



D. Glassy membrane. 



E. Fibrous wall of the follicle. 



with its follicle, is indicated in transverse section in Fig. 68. A 

 represents the medulla, and B the cortex of the hair. Outside the 

 root-sheath, C, and derived from the rete mucosum of the epider- 

 mis, is a thin layer, the glassy membrane, D. This is projected 

 from the basement membrane covering the surface of the corium, 



