THE BILIARY APPARATUS. 



1719 



ends at the point at which the cystic duct opens into it. The duct is lined with 

 mucous membrane, covered with simple columnar epithelium, and presents many 

 minute pits, into which open the orifices of numerous small tubular glands. Its 

 walls consist of fibro-elastic connective tissue and unstriped muscular fibres. The 

 latter, neither numerous nor separated into a distinct layer, are grouped for the 

 most part into longitudinal bundles, but there are also circular and oblique ones. 1 



The gall-bladder (vesica fellea) is a pear-shaped receptacle for the bile, rest- 

 ing in its fossa on the under side of the liver, with the large end forward. The 

 long axis runs also somewhat inward.. The length is from 8 10 cm. (3^4 in.) 

 and the capacity some 50 c.c. (about 1^2 fl. oz. ). It narrows to a point where 

 it usually bends to the left and ends in the cystic duct without definite external 

 demarcation. The bent terminal portion, or neck, about i cm. long, is more or 

 less closely bound beneath the peritoneum to the side of the gall-bladder, so that 

 before this is separated it sometimes looks as if the duct arose from the side of 

 the latter. 



The fundus of the gall-bladder lies near the end of the ninth right costal carti- 

 lage. The neck is at the right end of the portal fissure. Anteriorly the bladder 

 rests on the transverse colon, behind which it lies first to the right of and then above 

 the first part of the duodenum. 



FIG. 1453. 



Surface view of portion of mucous membrane of gall- 

 bladder. X 12. 



Portion of gall-bladder and biliary 

 passages laid open, showing surface of 

 mucous membrane. Natural size. 



The wall of the gall-bladder is very resistant, being composed of a mixture of 

 fibrous tissue and of unstriped muscular fibres. Most of the latter are disposed circu- 

 larly, but oblique and longitudinal ones are interwoven. The fibro-muscular tunic is 

 lined by a layer of mucous membrane which is very adherent to it. The mucous 

 membrane, covered with simple columnar epithelium, presents slightly raised ridges 

 marking off a net-work of small irregular spaces some 5 mm. in diameter. The 

 small bifurcated tubular glands are few and may be wanting. The bent portion, or 

 neck, is separated from the bladder by a strongly raised fold. There are, or may 

 be, one or two smaller folds within the neck, the separation of which from the duct 

 is usually arbitrary. 



Vessels of the Gall-Bladder. Arteries. The chief distribution of the 

 cystic artery, a branch of the hepatic, is on the free under surface, which it ap- 

 proaches from the left, running on the cystic duct. There is a smaller branch 

 which lies deeply on the right between the gall-bladder and the liver-substance. 

 Veins. The superficial veins join the cystic vein and empty into the right divi- 

 sion of the portal vein. According to Sappey, a number of small veins run 

 directly into the liver-tissue joining the portal system. The lymphatics, for the most 



1 For the musculature of the biliary apparatus, see Hendrickson : Johns Hopkins Hospital 

 Bulletin, Nos. 90, 91, 1898. 



