Page 28 - Ebook Digestive System Grade XI

3. Stomach
The stomach (ventricle) is a muscular organ on the upper abdomen's left side.
The stomach receives food from the esophagus. When Food reaches the end of the
esophagus, it enters the stomach through a muscular valve called the lower
esophageal valve. The stomach secretes acids and enzymes that digest food. The
stomach is composed of 3 parts, namely:
a.Cardiac, there is a cardiac sphincter muscle that will open if there is one
incoming food.
b. Fundus is the middle part of the stomach
with the shape of around.
c. The pylorus, the lower part of the stomach
adjacent to the small intestine,
Near the pylorus, there is a pyloric
sphincter that can move freely. Peristalsis is
the same as a movement in the esophagus. The
stomach wall produces the hormone gastrin
and gastric juice, which stimulates the
stomach wall to secrete sap stomach. Gastric juice contains hydrochloric acid
(HCl), the enzyme pepsin, lipase, and renin. Hydrochloric acid (HCl) kills germs
that come along with food, activates pepsinogen to pepsin, stimulates opens and
closes the pyloric sphincter, and stimulates the secretion of intestinal juice. Pepsin
functions to break down protein into peptones. Lipase functions to digest fat.
Renin functions to coagulate casein in milk.

Figure 11. Structure and anatomy stomatch

19