418 DIGESTIVE SYSTEM OF THE HORSE 
Saccus ceecus 
(left extremity) 
(Esophageal region 
(@sophagus 
Margo 
plicatus 
Fundus 
gland 
region Pyloric gland region 
Fic. 357.—FRontTAL Section or STOMACH AND First Part or DuopEeNuMm or Horse. 
C, Cardiac orifice. Photograph of specimen fixed in situ. 
tissue which connects the muscular and mucous coats; in it the vessels and nerves 
ramify before entering the mucosa. The mucous coat (Tunica mucosa) is clearly 
divided into two parts. That which 
lines the greater part of the left sac re- 
sembles the cesophageal mucous mem- 
brane, and is termed the cesophageal 
part (Pars cesophagea). It is white in 
color, destitute of glands, and covered 
with a thick, squamous, stratified epi- 
thelium. At the cardiac orifice it pre- 
sents numerous folds which occlude the 
opening.' It terminates abruptly, form- 
ing an irregular, sinuous, raised edge, 
termed the margo plicatus (or cuticular 
ridge). Below and to the right of this 
line the mucous membrane has a totally 
different character, being soft and vel- 
Fie. 358.—Diacram or Zones or Mucous MEMBRANE vety to the touch, and covered by uate 
or Sromacu or Horse. coid secretion. It contains the gastric 
glands (Glandul gastric), and is there- 
fore termed the glandular part (Pars glandularis). It is subdivided into three zones 
according to the types of glands which it contains, but no distinct lines of demar- 
- ? This occlusion is usually so complete that distention of the stomach by air or fluid forced 
in through the pylorus may be carried far enough to rupture the stomach without ligating the 
cesophagus. 
