The Digestive Process

Explain chemical digestion in the stomach.

1. The churning food makes contact with digestive juice (produced by cells in the stomach lining). This has pepsin, which chemically digests proteins in your food, making them into short chains of amino acids. 2. Digestive juice also has hydrochloric acid; it is important because pepsin functions best in an acid environment. It also kills a lot of bacteria that you swallow with your food.

What is the stomach?

A J-shaped pouch in the abdomen that expands to hold all of the food you swallow. Most mechanical digestion and some chemical digestion occur in the stomach.

Explain chemical digestion in the mouth.

A chemical called an enzyme in saliva breaks down food molecules.

What is bile? Where does it go?

A substance that breaks up fat particles. It flows to the gallbladder, the bile-storing organ.

Complete the sentence: Almost all _______ and _______ of _______ takes place in the small intestine.

Almost all chemical digestion and absorption of nutrients takes place in the small intestine.

What is an enzyme?

An enzyme is a protein that speeds up chemical reactions in the body. Each has a specific chemical shape. This shape enables it to take part in only one kind of chemical reaction.

Why doesn't hydrochloric acid burn a hole in your stomach?

Cells in the stomach lining produce a thick coat of mucus that protects the lining. Also, cells that line the stomach are quickly replaced as they are damaged or worn out.

What is the process by which your body breaks down food into small nutrient molecules?

Digestion

What are the three main functions of the digestive system?

First, break down food into molecules that the body can use. Second, molecules are absorbed into the blood and carried throughout the body. Third, wastes are eliminated from the body.

What happens in the esophagus?

Food stays in the esophagus for ten seconds. When it enters, contractions of smooth muscles push the food towards the stomach.

Where does the large intestine end?

In a tube called the rectum, where material is compressed into a solid form, and eliminated through the anus.

Where do mechanical and chemical digestion begin?

In the mouth.

What is the state of the food when it reaches the small intestine?

It has already been mechanically digested into a thick liquid. Chemical digestion has just begun, and starches and proteins have been partially broken down, but fats haven't been digested at all.

What is bile NOT? Why?

It is NOT an enzyme because it doesn't chemically digest food, but it breaks up large fat particles into smaller fat droplets.

What happens as the liquid moves into the small intestine?

It mixes with enzymes and secretions produced by the small intestine, the liver, and the pancreas.

What are the two forms of digestion? Explain both.

Mechanical: Foods are physically broken down into smaller pieces. It occurs when you bite into a food and chew it into smaller pieces. Chemical digestion: Chemicals produced by the body break foods into their smaller chemical building blocks

What has happened by the time material reaches the end of the small intestine? What is in the material? Where does it go?

Most nutrients have been absorbed. It is mostly water and undigested food. It goes to the large intestine.

What is saliva?

The fluid released when your mouth waters.

What is peristalsis?

The involuntary wave of muscle contractions that pushes food towards the stomach. It also occurs in the stomach and other places. It keeps the food going in one direction.

What is the small intestine?

The part of the digestive system where most chemical digestion takes place.

What is absorption? What happens to materials that are not absorbed?

The process by which nutrient molecules pass through the wall of your digestive system into your blood. Materials not absorbed are eliminated from the body as wastes.

What is mechanical digestion in the stomach?

Three strong layers of muscle contract to produce a churning motion, which mixes the food with the fluids.

What is the role of villi? How do they work?

To absorb nutrient molecules in the small intestine. Nutrient molecules pass from cells on the surface of each villus and into the blood vessels within, through which the blood carries the nutrients to the body.

What is the role of the live?

To produce bile.

What is the role of the pancreas?

To produce enzymes that flow into the small intestine and help break down starches, proteins, and fats.

How many openings are there in the back of your mouth? What are they?

Two. One is the windpipe. A flap of tissue called the epiglottis closes it off as you swallow to precent from entering. The other is the esophagus, which food goes down. It is a muscular tube connecting the mouth to the stomach, and is lined with mucus that makes food easier to swallow and move along.

How along does the food remain in the stomach? What has happened thus far in the stomach?

Until all of the solid material has been broken down into liquid form. The stomach completes mechanical digestion, and most proteins have been chemically digested into shorter chains of amino acid. The food is a thick liquid released into the next part of the digestive system.

What happens as food moves through the large intestine ?

Water is absorbed into the large bloodstream, and remaining material is readied for elimination from the body.

Explain mechanical digestion in the mouth.

Your teeth carry out the first stage of mechanical digestion. The incisors cut the food into bite-sized pieces. Canines make the food into smaller pieces. Premolars and molars crush and grind the food. Saliva makes the food into one slippery mass.