TEETH. 



75 



coarse bundles, and the cell processes remain evident. Elastic elements 

 are absent. The small arteries entering the apical foramen send capillaries 

 close to the odontoblasts, but they do not enter the dentine. There are no 

 lymphatic vessels in the pulp. The medullated dental branches of the 



Dental sac. 



Outer layer. Inner layer 



OutejAamel cells. 



Dental papilla (future 



FIG. 86. LONGITUDINAL SECTION OP A DECIDUOUS TOOTH OF A NEWBORN DOG. X 42- 

 The white spaces between the inner enamel cells and the enamel are artificial, and due to shrinkage. 



alveolar nerves pass through the foramen, lose their sheaths and form a loose 

 plexus beneath the odontoblasts, between which they terminate in free 

 endings. Odontoblasts persist throughout the life of a tooth, and in case 

 of disease or injury they may deposit dentine as a reparative process. 



