Digestive System

Which macromolecule(s) is/are digested in the stomach and small intestine? Which macromolecule(s) is/are digested only in the small intestine?

Proteins. Fats/Sugars.

What is chemical digestion in the mouth? (What does it involve?)

Chemical digestion in the mouth involves the action of enzymes. Salivary glands moisten the food and contains amylase, which breaks down starches into sugars. The tongue then moves the food to the esophagus.

What is the digestive system?

A collection of organs that break down food into energy that can be used in cells.

What is digestion?

Digestion is the process by which large complex molecules in food are broken down into smaller molecules that can be used by the body.

What happens in the process of digestion (interactions?)

Digestion takes place through the interaction of enzymes, stomach acid, hormones, bile from the liver, and a network of nerves and muscles.

What flows through ducts to the duodenum to help complete digestion?

Enzymes and hormones from the pancreas, liver, and gallbladder.

What organ stores bile?

Gallbladder.

What are sphincters?

Sphincters are rings of muscle which separate one section of the body from another.

What is the function of pepsin? Where is it located?

Pepsin is located in the stomach, and it breaks down proteins.

What is the function of peptidase? Where is it located?

Peptidase breaks down proteins into amino acids, and is located in the small intestine.

What happens after the food gets digested in the stomach?

Peristaltic actions push the chyme against the sphincter that separates the stomach and the small intestine. Chyme squirts into the small intestine.

What is the primary function of the digestive system?

To break down and absorb nutrients, salts, and water, as well as to eliminate some wastes.

What is absorption?

Absorption is the process by which nutrients move out of the digestive organs and into the circulatory and lymphatic systems.

What is the function of amylase? Where is it located?

Amylase continues the breakdown of starches, and is located in the small intestine and pancreas.

What does the pancreas release when chyme first enters the small intestine?

An alkaline fluid to help neutralize the acid and stop the action of pepsin. Also releases enzymes to further break down starches into sugars.

What is mechanical digestion in the mouth? What organs perform mechanical digestion? What happens to the food?

Chewing/mastication. Teeth, tongue, lips. The food is turned into a bolus.

What is the stomach?

A muscular sac that can expand to nearly twice its original size, and hold up to 2 L of food.

What is the pancreas?

A small gland located behind the stomach.

In what three organs are nutrients absorbed in the small intestine?

Duodenum, jejunum, ileum.

What is gastric juice? What does it contain?

Gastric juice is secreted by the stomach lining and contains HCl (hydrochloric acid) and pepsin.

What is the function of salivary amylase? Where is it located?

It breaks down complex starch molecules into sugars. Mouth.

What are the mechanical and chemical digestion processes in the small intestine?

Mech: Muscular contractions break down food and mixes it with digestive enzymes, bile, and hormones. Chem: Enzymes, bile, and hormones finish the digestion of protein, sugars, and fats.

What does the remaining undigested material in the large intestine form? What is it called, where it is stored and how is it excreted?

The remaining undigested material forms a solid mass called feces. The feces is stored in the rectum, and eliminated through the anus.

What is the function of lipase? Where is it located?

Lipase helps break down fats, and is located in the small intestine and pancreas.

What does lipase do? What organ produces it?

Lipase, which is produced by the pancreas, splits fat into fatty acids and smaller molecules.

What happens in mechanical digestion in the stomach? Chemical digestion?

Mech: Smooth muscle contractions in the stomach churns food to break it down, and mixes it with digestive juices. Chem: The stomach lining secretes gastric acid. Digestive juices and enzymes turn the bolus into chyme (semi-liquid).

What are the two types of digestion that occurs in your mouth?

Mechanical and chemical digestion.

What are microvilli? What do they do?

Microvilli are thousands of tiny projections on the villi, which add even more surface area to absorb nutrients.

Where does most digestion take place? Describe the organ.

Most digestion takes place in the small intestine, which is a long, narrow tube.

What is absorbed by the villi in the duodenum? Where do the nutrients go?

Most simple sugars, amino acids, and minerals (calcium, iron) are absorbed by the villi in the duodenum. The nutrients are then diffused into the circulatory system and are distributed throughout the body.

What is the function of mucus in the stomach?

Mucus protects the stomach from its own acidic environment.

What leaves the small intestine and enters the liver? What do enzymes in the liver do? What is stored in the liver tissues?

Nutrient rich blood. Enzymes in the liver use some nutrients to build more complex molecules. Some nutrients are also stored in the liver tissues.

What happens after digestion is complete?

Nutrients are absorbed by the body and transported by the circulatory and lymphatic systems to all the cells. Undigested materials are then eliminated as liquids and solid wastes.

What is peristalsis?

Peristalsis is the contraction of smooth muscles to help push food down the esophagus.

What process keeps the food moving down the esophagus?

Peristalsis.

What does the large intestine/colon do?

The large intestine/colon absorbs water to maintain the body's fluid balance.

What does liver produce? What does it do?

The liver produces bile, which helps to further break down/digest fats.

What is absorbed by the villi in the ileum? Where do the nutrients go?

The villi in the ileum absorb fat soluble vitamins, vitamin B12, fatty acids, cholesterol, and some water. The nutrients empty into the lymph and blood vessels and are distributed to the cells.

What is absorbed by the villi in the jujenum? Where do the nutrients go?

The villi in the jujenum absorb glucose, amino acids, vitamin C, most B vitamins, some water. These nutrients are then diffused into the circulatory system and are distributed throughout the body.

What is the function of maltase, lactase, and sucrase? Where are they located?

They break sugars into simpler molecules, and are located in the small intestine.

Why is the lining of the small intestine ridged and folded?

To increase surface area, and slow the passage of material through the small intestine. This allows for a greater absorption of nutrients.

What is the function of trypsin? Where is it located?

Trypsin helps break down proteins. It is located in the small intestine and pancreas.

What are villi? What do they do?

Villi are small fingerlike projections, covered with epithelial cells, that absorb nutrients. They cover the folds of the small intestine lining.

What are the three main structures of the small intestine, and what is their purpose?

Villi, microvilli, and lining absorb most of the nutrients from chyme.