STRUCTURE OF GALL-BLADDER. 



473 



The mucous coat is marked internally by numerous ridges and interven- 

 ing depressions, which give an areolar or honeycomb appearance to the sur- 

 face. On laying open the gall-bladder this condition 

 will be seen, with the aid of a lens, to be most developed Fig. 162. 



about the centre of the sac, and to diminish towards 

 each extremity. In the bottom of the larger pits 

 are depressions leading to recesses. The surface of 

 the mucous membrane is covered by a columnar epi- 

 thelium. 



Where the gall-bladder ends in the cystic duct (fig. 

 162) its coats project into the interior, and give rise 

 to ridges resembling those in the sacculated large in- 

 testine. 



The cystic duct (b) joins the hepatic duct at an 

 acute angle, to form the ductus communis choledo- 

 chus. It is about an inch and a half long, and is dis- 

 tended and somewhat sacculated near the gall-bladder. 



Structure. The coats of the duct are formed like 

 those of the sac from which it leads, but the muscular 

 fibres are very few. The mucous lining is provided 

 with glands, as in the hepatic and common bile ducts 

 (p. 472). 



On opening the duct the mucous membrane may be 

 observed to form about twelve semilunar projections 

 (fig. 162, c), which are arranged obliquely around the 

 tube, and increase in size towards the gall-bladder. 

 This structure is best seen on a gall-bladder which 

 has been inflated and dried : as in this state the parts 

 of the duct between the ridges are most stretched. 



Bloodvessels and nerves. The vessels of the gall- 

 bladder are named cystic. The artery is a branch 

 of the hepatic ; and the cystic vein opens into the vena 

 portae near the liver. The nerves are derived from 

 the hepatic plexus, and entwine around the vessels. 

 The lymphatics follow the cystic duct, and join the deep lymphatics on 

 the spinal column. 



GALL-BLADDER AND ITS 

 DUCT 



a. Gall-bladder. 



b. Bile duct sacculated. 



c. Ridges in the interior. 



d. Common bile duct. 



e. Common hepatic duct. 



THE KIDNEY AND THE URETER. 



The kidney has a characteristic form : flattened on the sides, it is larger 

 at the upper than the lower extremity, and is hollowed out at one part of its 

 circumference. For the purpose of distinguishing between the right and 

 left kidneys, let the excavated margin be turned to the spinal column, with 

 the ureter or the excretory tube behind the other vessels ; and let that end 

 be directed downwards, towards which the ureter is naturally inclined. 



With the special form above mentioned, the kidney is of a deep red 

 color, with an even surface. Its average length is about four inches ; its 

 breadth two ; and its thickness about one inch ; but the left is commonly 

 longer and more slender than the right kidney. Its usual weight is about 

 five ounces and a half in the male, and rather less in the female. 



The upper extremity of the kidney is rounded, is thicker than the lower, 

 and is surmounted by the suprarenal body. The lower end is flat, and 



