CH. xxvii.] STRUCTURE OF THE STOMACH. 443 



cardiac portion of the stomach ; they form a sphincter around the 

 cardiac orifice. The muscular fibres of the stomach and of the 

 intestinal canal are unstriated, being composed of elongated, 

 spindle-shaped fibre-cells. 



(3) The submucous coat consists of loose areolar tissue, which 

 connects the muscular coat to the mucous membrane. It con- 

 tains blood-vessels and nerves; in the contracted state of the 

 stomach it is thrown into numerous, chiefly longitudinal, folds 

 or rugae, which disappear when the organ is distended. 



(4) The mucous membrane is composed of a corium of fine 

 connective tissue, which approaches closely in structure to adenoid 

 tissue ; this tissue supports the tubular glands of which the 

 superficial and chief part of the 



mucous membrane is composed, 

 and passing up between them 

 assists in binding them together. 

 The glands are separated from 

 the rest of the mucous membrane 

 by a very fine homogeneous base- 

 ment membrane. The corium is 

 covered with a layer of columnar 

 epithelium, which passes down 



intr thp months of thp elands Fi S- 374- Transverse section through 



e gianas. lower p art of g^a^ glandg of a ^ 



At the deepest part of the . parietal cells; 6, central cells; 



. . c, transverse section of capillaries. 



mucous membrane are two thin (Frey.) 



layers (circular and longitudinal) 



of unstriped muscular fibres, called the muscularis mucosce, 



which separate the mucous membrane from the scanty submucous 



tissue. 



When examined with a lens, the internal or free surface of the 

 stomach presents a peculiar honeycomb appearance, produced by 

 shallow polygonal depressions, the diameter of which varies 

 generally from ^-^th to 7 ^th of an inch (about 125^); but near 

 the pylorus is as much as y^j-th of an inch (250/^1). In the 

 bottom of these little pits, and to some extent between them, 

 minute openings are visible, which are the orifices of the ducts of 

 I>erpendicularly arranged tubular glands (fig. 373), imbedded side 

 by side in sets or bundles, on the surface of the mucous 

 membrane, and composing nearly the whole structure. 



The glands of the mucous membrane are of two varieties, 

 {a) Cardiac, (b) Pyloric. 



(a) Cardiac glands are found throughout the whole of the 

 cardiac half and fundus of the stomach. They are arranged in 

 groups of four or five, which are separated by a fine connective 



