14 



PHYSIOLOGY OF FARM ANIMALS 



FCH. 



manner of flat paving-stones closely fitted together such as we find 

 surrounding the air sacs of the lungs. Such a tissue is described 

 as a pavement epithelium. 



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Fig. 4. Ciliated epithelium from trachea 

 (from Gray), a elastic fibres within, 

 b, c, d epithelial cells of mucous 

 membrane, e ciliated ej)ithelial cells. 



Fig. 5. Transitional epithelium (from Gray). 



Fig. 6. Stratified epithelium from 

 oesophagus (from Gray). 



In compound epithelia the tissue consists of more than one 

 layer of cells. When the cells are arranged in two, three or four 

 superimposed layers the epithelium is frequently called transi- 

 tional, but if the number of layers is considerable, we speak of 

 a stratified epithelium. The tissue lining the urinary bladder is 



