ELECTRON iMICROSCOPY 



Structure are attached lo the nienihraiiesof the rough- 

 Goblet cell. The goblet cell cytoplasm is surfaced endoi)lasinic reticulum (ergasto- 

 characterized by a high content of ribonu- plasm). Precursors of the mucin are evi- 

 cleic acid (RNA) particles, some of which dently formed within the cisternae which are 



Fig. 2. Detail ol I'ig. 1 shuwing twu muc-ous cells (G) and one ciliated cell (C). 

 The mitochondria (m) are abundant in the upper part of the ciliated cell in which the 

 Golgi apparatus (go) is also seen. The cilia (cl) emerge from basal bodies at the top 

 of the cell into the tracheal lumen together with a nmnber of microvilli (mv) beneath 

 which a dense structure, the terminal web (tw), is resolved. The cells are attracted 

 by the terminal bar (tb). The mucous cells (G) are filled with mucin granules which 

 are about to be discharged at the cell surface. Magnification 6,000X 



118 



