1.17. Enzymes in the Digestive System http://www.ck12.org
- Deoxyribonuclease and ribonuclease, produced in the pancreas. They are enzymes that break bonds in nucleic
acids like DNA and RNA.
Bile salts are bile acids that help to break down fat. Bile acids are made in the liver. When you eat a meal, bile is
secreted into the intestine, where it breaks down the fats (Figure1.32).
FIGURE 1.32
Bile is made in the liver, stored in the
gallbladder, and then secreted into the
intestine. It helps break down fats.Hormones and Digestion
If you are a typical teenager, you like to eat. For your body to break down, absorb and spread the nutrients from
your food throughout your body, your digestive system andendocrine systemneed to work together. The endocrine
system sendshormonesaround your body to communicate between cells. Essentially, hormones are chemical
messenger molecules.
Digestive hormones are made by cells lining the stomach and small intestine. These hormones cross into the blood
where they can affect other parts of the digestive system. Some of these hormones are listed below.
- Gastrin, which signals the secretion of gastric acid.
- Cholecystokinin, which signals the secretion of pancreatic enzymes.
- Secretin, which signals secretion of water and bicarbonate from the pancreas.
- Ghrelin, which signals when you are hungry.
- Gastric inhibitory polypeptide, which stops or decreases gastric secretion. It also causes the release of insulin
in response to high blood glucose levels.
Vocabulary
- endocrine system: Body system of endocrine glands, each of which releases a hormone directly into the
bloodstream to regulate body processes. - enzyme: Protein that speeds up chemical reactions in the body.
- hormone: Chemical messenger used to communicate between cells.