BIOLOGY 12
12: Digestive System
Worksheet
Name:______
Block______
1. Food is received by the ______, which possesses ______to grind and break up particles. ______glands secrete ______that moisten food and binds it together for swallowing. The taste of food is detected by ______located on the ______.
2. At the back of the mouth, the muscular ______is involved in swallowing food. The epiglottis folds over the glottis during the swallowing ______.
3. The esophagus propels food toward the ______, using muscular contractions called ______At the lower end of the esophagus, a muscular ring called a(n) ______regulates the entrance of food to the stomach.
4. The stomach is lined with ______that secretes protective ______. Otherwise, the lining would be injured by the strong ______acid secreted by ______glands. Gastric juice also contains ______that breaks down proteins.
5. The first section of the small intestine is the ______. It receives secretions from the ______and ______and also receives food known as ______from the stomach.
6. The mucosa of the small intestine is folded into ______, which, in turn, have projections from individual cells called ______. Proteins in the microvilli transport nutrients such as ______directly into the bloodstream, and fats must be reconstructed so they can travel into vessels of the lymphatic system called ______.
7. A number of hormones control the secretions of digestive juices. ______is secreted in response to protein in foods and enhances gastric gland output, while ______inhibits gastric secretions. ______is secreted in response to acidic chyme. When fats are present in chyme, ______triggers the release of bile from the gallbladder.
8. The large intestine functions to store and compact ______. Unusual outgrowths of the lining of the colon, called ______, can be either benign or cancerous. Colon cancer incidence increases for people who do not have enough ______in their diet.
9. Pancreatic juice contains a mix of ______solution to neutralize stomach acid, and digestive ______to further break down food.
10. The liver produces a greenish substance called ______, which is stored and concentrated by the ______. The liver has been called the ______to the blood because it detoxifies substances entering the blood from the ______.
11. ______is a fat-digesting enzyme produced by the accessory organ, the ______. Starch digestion begins in the ______with salivary ______and continues in the ______with pancreatic ______.
12. Protein digestion begins in the ______where the enzyme ______is produced, and continues in the small intestine with the aid of the enzyme ______from the pancreas.