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48 ORGANS OF DIGESTION AND ALIMENTARY TRACT. 
are seen here and there single, large, oval cells, each having a large 
nucleus. These are called oxyntic cells ; they are supposed to secrete the 
free acid of the stomach and are a characteristic feature of the cardiac 
end. Little nodules of lymphoid tissue, sometimes visible to the naked 
eye, are seen in the mucous membrane and are called lenticular glands 
or nodules, 
How are the blood and lymphatic vessels distributed to the 
stomach and intestines ? 
They branch and subdivide in the sub-mucous coat and send 
branches up between the gland tubules. 
How are the nerves distributed ? 
Branches from the sympathetic and pneumogastric anastomose and 
form the plexus of Auerbach in the muscular coat of the canal, 
dividing and anastomosing again in the sub-mucous coat to form Meiss- 
ner’s plexus; they are finally distributed between the gland tubules. 
What are the peculiarities of the mucous membrane of the small 
intestine ? 
It is much more complex than the mucous membrane of the stomach. 
The connective-tissue framework of the mucous membrane is more 
richly infiltrated with lymphoid cells than that of the stomach. Situ- 
ated in this mucous membrane are numerous tubular glands (erypts 
of Lieberkiihn). Between them the mucous membrane projects up 
into cylindrical or cone-shaped bodies, called eZ. In the sub-mucous 
coat of the upper part of the small intestine are a number of racemose 
glands called Brunner’s glands. 
Describe the structure of the villi of the small intestine. 
They consist of a connective-tissue framework infiltrated with round 
cells, and in this loose structure the bloodvessels and lymphatics 
ramify. The villi are covered with a layer of cylindrical cells, the free 
borders of which are quite thick. 
Some of the cells seem to have lost this free border and to have 
become goblet shaped on account of a swelling up and expulsion of 
the cell-protoplasm ; they are called goblet cells. Smooth muscle cells 
pass up into the villi from the muscularis mucosze. 
What is the structure of Brunner’s glands ? 
They are racemose glands having rather oval-shaped alveoli lined 
with polyhedral-shaped epithelium. The ducts are lined with cylin- 
drical epithelium. These glands probably-secrete nothing but mucus. 
