340 THE UEINO-GENITAL SYSTEM, THE ADEENALS, ETC. 



The cells of all three layers possess a cell-wall, and finely gran- 

 ular contents, and each cell has a large oval nucleus (List). 



The goblet-cells (Fig. 221 I and IV, d] vary very much in shape; 

 they are always more or less rounded in outline : they vary greatly 

 in size (from 190 /x to 54 ju in length) ; some possess ' feet ' or basal 

 prolongations, in others these are absent. They usually open freely 

 by rounded apertures on the surface of the mucous membrane, 

 but are sometimes closed. The nucleus is placed towards the base 

 of the cell and surrounded by a smaller or larger amount of proto- 

 plasm. These cells usually extend into the middle layer of the 

 epithelium, and they probably constitute unicellular mucous glands 

 (List). 



(4) The blood-vessels of the urinary bladder (p. 235) are very 

 numerous and run in very tortuous courses ; they are accompanied 

 by large lymphatics and by nerves. 



(5) The nerves of the urinary bladder (p. 191) are of both medul- 

 lated and non-medullated fibres, which course together towards 

 their points of distribution ; the non-medullated fibres are, however, 

 much more frequent than the medullated fibres (Wolff). 



The non-medullated nerve-fibres stand in close relation with the 

 nerve-ganglia of the bladder. These ganglia may be unicellular, or 

 composed of groups of nerve-cells ; the cells vary considerably in 

 shape, round, oval, triangular, and other forms being equally 

 frequent in their occurrence ; to some extent the form appears to 

 depend upon the number and position of the processes of the cells. 

 The diameter of the cells varies from 0*05 mm. to o - i mm.; the 

 nucleus has a diameter of 0-025 mm., that of the nucleolus measures 

 0-005 mm - (Wolff). 



The cells may be unipolar or multipolar ; the former are however 

 rare. The processes of these cells supply the muscle-fibres (Fig. 

 221 V, a), and other non-medullated processes connect the cells 

 with the nerves (V, 6 (Wolff) ). 



The number of muscular fibres is far in excess of the number of 

 the fibres of distribution of the ganglia ; Wolff hence concludes 

 that the nervous impulse may pass from one muscle-fibre to 

 another.] 



