VIII 



LIVER 



133 



The submucosa of the stomach is traversed by a narrow 

 band of unstriped muscle, the vniscularis mucnsce, formed, 

 Hke the main muscular layer, of an outer layer of longitudinal 

 {l.iii.m) and an inner of circular (cm. in) fibres. 



A nnisciilaris niucosn; is also present in the intestine, Ijiit as it is very 

 thin, it may easily l)e overlooked. 



The Liver. — Sections of the liver show it to be made up 

 of innumerable large, polyhedral cells (Fig. 41, <■), which are 





Fro 4T. — A, portion ol a <;ection of the frog's liver ; R, smal' portion of the =:ame, 

 showing the origin of a bile-duct, 

 /j. c. blood-capillaries, in section; /•./. bile-passages ; c. liv'er cells; </, smallest 

 bile-duct ; nn. nuclei. (After Hoffmann.) 



so arranged as to bound extremely fine channels or hik- 

 passai;es {b.p). These are found to open into one another, 

 and finally to discharge into definite tubes (B, d), lined with 

 epithelium. These, in their turn, unite into larger and larger 

 tubes, which form the hepatic ducts and ultimately open into 

 the common bile-duct (p. 68). 



The liver-cells are glandular and secrete the bile, which, 

 as it is formed, drips into the bile passages and passes into 



