DIGESTIVE ORGANS 
409 
(ap-pend-i-sl'tis) affects this organ. The 
large intestine ends in a special region 
called the rectum. The opening of the 
rectum to the outside is the anus (a/nus). 
The esophagus, stomach, and intestine 
are each lined with a membrane that is 
similar to that found in the mouth cavity. 
This membrane is called the mucous 
membrane. In the esophagus, the mucous 
membrane is smooth and moist thus fur¬ 
nishing an easy passage for the food; in 
the stomach this membrane is in folds 
except when the stomach is full of food; 
and in the intestine, it has a velvet ap¬ 
pearance due to projections called villi 
(Figure 374). The numerous glands of 
the stomach and intestine are located 
in the mucous membrane. 
Glands. — A gland is a group of special cells which secrete a 
fluid. The glands which produce 
the digestive fluids are (1) the three 
pairs of salivary (sal'i-va-ry) glands, 
located below the ear, and beneath 
the tongue and lower jaw; (2) the 
numerous gastric (gas'trik) glands 
found in the lining of the stomach, 
possibly 5,000,000 in number (Fig¬ 
ure 373); (3) the pancreas; (4) the 
liver, the largest gland in the body; 
and (5) numerous intestinal glands 
in the small intestine. 
STUDENT REPORT 
Fill out the following table and de- 
The constrictions are natural, scribe the digestive system of the animals 
Figure 372. — X-ray Photo¬ 
graph of Large Intestine 
of Man Showing Appendix. 
Figure 371. — X-ray 
Photograph of 
Human Stomach. 
This is a shape 
familiar to physi¬ 
cians and is just as 
normal as the shape 
shown in Figure 370. 
