i8o 



HISTOLOGY 



tr. 



long processes, as well as on account of its many and intense activities. 



It is not, therefore, all drawn out into processes, even in its most differ- 

 entiated forms, but retains a 

 large portion of its cytoplasm 

 for the undifferentiated trophic 

 functions. This part of the cy- 

 toplasm, the cell body, possesses 

 in its mass and usually near the 

 center a large, well-formed nu- 

 cleus (see Fig. 156). 



The nucleus in general re- 

 sembles that of an ovum or 

 spermatogonium. It is spheri- 

 cal (Figs. 156, 157, and 158) or 

 irregularly rounded (Figs. 160 

 and 161). The nuclear mem- 



FIG. 156. Nerve cell from the stellate ganglion of i .1- i j r i j 



a squid, Loligo Pealii. tr., trophofpongia or brane 1S thl <* and sharply ^de- 



lymph and blood channels; conn.l.fi., connec- fined, and while a distinct linin 



tive-tissue fibrils entering to support the cell body. netwQrk ig not always visible> j t 



is typical in most nerve cells, especially where the chromatin is distrib- 

 uted in masses of any considerable size (see Fig. 158). 



The chromatin is arranged in many ways. It may be distributed 

 throughout the nucleus in such fine particles as to appear merely as a 





FIG. 157. Large motor ganglion cell from the electric lobe of the brain of the torpedo, Tetron- 

 arce. imp.c., implantation cone; ch.nu., chromatin knot; den., dendriteS shown at their 

 beginning. The chromatin nucleolus is always placed opposite to the nucleolus or plasmo- 

 some and the axis thus formed is the same in all the electric cells. 



ground color when stained. More often it appears as a considerable 

 number of fine but visible particles of varying sizes strung out on the 

 linin network and especially at the intersections of the fibrils (see Fig. 



