PHYSIOLOGICAL ANATOMY OF THE STOMACH. 229 



quite small. The size of the pits is very variable, but the average is about ^TJ of an 

 inch. This appearance is not distinct toward the pylorus; the membrane here present- 

 ing irregular, conical projections and well-marked villi resembling those found in the 

 small intestine. The surface of the mucous membrane is covered with columnar or pris- 

 moidal epithelium, the cells being tolerably regular in shape, each with a clear nucleus 

 and a distinct nucleolus. 



The thickness of the mucous membrane of the stomach varies in different parts. It 

 is usually thinnest near the oesophagus and thickest near the pylorus. Its thinnest portion 

 measures from 7 ^ to ^ of an inch ; its thickest portion, from T \ to ^ of an inch ; and 

 the intermediate portion, about ^ of an inch. 



Glandular Apparatus of the Stomach. Extending from the bottoms of the pits in the 

 mucous membrane of the stomach to the submucous connective tissue, are immense num- 

 bers of racemose glands. These are generally arranged in tolerably distinct groups, sur- 

 rounded by fibrous tissue, each group belonging to one of the polygonal depressions. 

 The tissue which connects the tubes is dense but not abundant. There are marked dif- 

 ferences in the anatomy of the glands of the stomach in different parts of the organ, 

 which are particularly interesting, as they are supposed to correspond with differences in 

 the function of various parts of the mucous membrane. There are, indeed, two distinct 

 varieties of glands; the gastric glands, found throughout the organ, except in the pyloric 

 portion, and the mucous glands found chiefly in the pyloric portion, with a few scattered 

 irregularly through the other portions of the mucous membrane. These demand special 

 consideration, as the former are supposed to secrete the gastric juice and are active only 

 during digestion, while the latter secrete a glairy mucus, which is not produced specially 

 during digestion and which has no distinct digestive function with which we are ac- 

 quainted. 



Gastric, or Peptic Glands. These glands are found throughout the entire extent of 

 the mucous membrane of the stomach, except around the pyloric orifice and in the lesser 

 pouch. In the human subject, their distribution, as compared with that of the mucous 

 glands, is much wider than in most of the inferior animals. They vary in their length 

 with the variations in the thickness of the mucous membrane. Recent researches have 

 shown that all of these glands are racemose. They present, in the upper fourth or fifth of 

 their length, a single tube, lined by a continuation of the columnar epithelium covering the 

 surface of the mucous membrane. Below this, they divide into several branches, pri- 

 mary and secondary, and are lined with rounded cells of glandular epithelium, having the 

 appearance of simple racemose glands. The cells lining the branching tubes are some- 

 times called peptic cells. They each have a nucleus and a nucleolus, contain numerous 

 granules, and are about T ^Vir of an in ch in diameter. This is the general character of the 

 glands in the greater part of that portion of the mucous membrane which secretes the 

 gastric juice. They readily undergo post-mortem alteration, and, in the human subject, 

 are only to be seen satisfactorily in the fresh stomachs of subjects who have died sud- 

 denly, having previously been in a condition of perfect health. 



Mucous Glands. Near the pyloric extremity of the stomach and in the lesser pouch, 

 where the mucous membrane is decidedly paler than over the rest of the organ, the 

 character of the glands is peculiar. As a rule, the glands in these situations are com- 

 pound ; but they do not present more than two or three divisions until they have passed 

 through about one-half of the thickness of the mucous membrane, when they break up 

 into numerous small secondary tubes. The important peculiarity of these glands is 

 that they are lined throughout with columnar epithelium and are everywhere deprived 

 of the cells found in the true peptic glands. The structure of the glands from different 

 portions of the stomach is shown in Fig. 57. 



Closed Follicles. In the substance of the mucous membrane, between the tubes and 

 near their c&cal extremities, are occasionally found closed follicles, like the solitary glands 



