FOOD AND DIGESTION 343 



The portal vein which takes blood from the stomach, in- 

 testine, pancreas, and spleen breaks up in the liver (fig. 107, 

 p. 225), and carries the blood between the lobules. From the 

 interlobular branches, capillaries run inwards and enter a 

 central vein which carries the blood from each lobule, and 

 pours it into the hepatic veins which join the inferior vena 

 cava. The supporting tissue of the liver is supplied by the 

 hepatic artery ; and the terminal branches have a very free 

 communication with those of the portal vein. 



The Pancreas is essentially the same in structure as the 

 parotid gland. But in the 



lobules are certain little ^-. ' ^>'v 



masses of epithelium - like 

 cells closely packed together, 

 the Islets of Langerhans (fig. 

 153). 



The Nerve Supply of the ali- 

 mentary canal. The muscles 

 round the mouth are supplied 

 by the fifth, seventh, and 

 twelfth cranial nerves. The 

 nerve supply of the salivary 

 glands will be considered 

 later. The pharyngeal 

 muscles are supplied by the 

 ninth and tenth cranial 

 nerves, and the oesophagus 



' . FIG. 153. Section of Pancreas to show 



is Supplied by the tenth. Acini of Secreting Cells ; a large duct ; 



The Stomach and intestine and in the centre an Island of Langer- 



get their nerve fibres from hans> 



two sources (fig. 76, p. 153) above the descending colon from 

 the vagus and the abdominal sympathetic, and below this from 

 the nervi erigentes and abdominal sympathetic the various 

 fibres passing through the abdominal sympathetic ganglia. 

 In the wall of the stomach and intestine, these nerves end 

 by forming an interlacing set of fibres, with nerve cells upon 

 them, from which fibres pass to the muscles and glands. One 

 of these plexuses (Auerbach's) is placed between the muscular 

 coats the other (Meissner's) is placed in the submucosa. 



