9. The Gullet.—At the back part of the throat begins a narrow tube, which passes down to the stomach. This tube is about nine inches long. It is called the gullet, food-pipe, or œsophagus (e-soph´-a-gus).
10. The Stomach.—At the lower end of the œsophagus the digestive tube becomes enlarged, and has a shape somewhat like a pear. This is the stomach. In a full-grown person the stomach is sufficiently large to hold about three pints. At each end of the stomach is a narrow opening so arranged that it can be opened or tightly closed, as may be necessary. The upper opening allows the food to pass into the stomach, the lower one allows it to pass out into the intestines. This opening is called the pylorus (py-lo´-rus), or gate-keeper, because it closes so as to keep the food in the stomach until it is ready to pass out.
11. In the membrane which lines the stomach there are many little pocket-like glands, in which a fluid called the gastric juice is formed. This fluid is one of the most important of all the fluids formed in the digestive canal.
GASTRIC GLAND.
12. The Intestine(in-tes´-tine).—At the lower end of the stomach the digestive canal becomes narrow again. This narrow portion, called the intestine, is about twenty-five feet long in a grown person. The last few feet of the intestine is larger than the rest, and is called the colon. This long tube is coiled up and snugly packed away in the cavity of the abdomen. In the membrane lining the intestines are to be found little glands, which make a fluid called intestinal juice.
13. The Liver.—Close up under the ribs, on the right side of the body, is a large chocolate-colored organ, called the liver. The liver is about half as large as the head, and is shaped so as to fit snugly into its corner of the abdomen. The chief business of the liver is to make a fluid called bile, which is very necessary for the digestion of our food.
14. The bile is a bitter fluid of a golden-brown color. It is carried to the intestine by means of a little tube or duct, which enters the small intestine a few inches below the stomach. When the bile is made faster than it is needed for immediate use, it is stored up in a little pear-shaped sac called the gall-bladder, which hangs from the under side of the liver.
15. The liver is a very wonderful organ, and does many useful things besides making bile. It aids in various ways in digesting the food, and helps to keep the blood pure by removing from it harmful substances which are formed within the body.
16. The Pancreas(pan´-cre-as).—The pancreas is another large and very important gland which is found close to the stomach, lying just behind it in the abdominal cavity. The pancreas forms a fluid called the pancreatic juice, which enters the small intestine at nearly the same place as the bile.