7TH -The Digestive System 5.1

​The Digestive System 5.1

Digestion

the mechanical and chemical breakdown of food into small particles and molecules that your body con absorb and use.

Mechanical Digestion

when food is physically broken into smaller pieces.

Chemical Digestion

chemical reactions break down pieces of food into small molecules.

Enzymes

Proteins that help break down larger molecules into smaller molecules.

Esophagus

a muscular tube that connects the mouth to the stomach.

Peristalis

Food moves through the esophagus and the rest of the digestive tract by waves of muscle contractions.

Chyme

a thin watery liquid

Villi

The folds of the small intestines are covered with fingerlike projections.

• digestion

• absorption

• saliva

• enzyme

Vocabulary

• What functions are carried out in the digestive system?

• What roles do the mouth, esophagus, and stomach play in digestion?

Key Concepts

The Digestive Process Begins

• epiglottis

• esophagus

• mucus

• peristalsis

• stomach

Discover Activity

How Can You Speed Up Digestion?

1. Obtain two clear jars with lids. Fill the jars with equal amounts of water.

2. Place a whole sugar cube into one jar and a crushed sugar cube into the other jar.

3. Fasten the lids on the jars. Holding one jar in each hand, shake the two jars gently for equal amounts of time.

4. Place the jars on a flat surface and observe whether the whole cube or crushed cube dissolves faster.

Multiple Choice

Which would take longer to digest?

• A large piece of food

• Food that has been cut up into many small pieces

In 1822, a man named Alexis St. Martin was wounded in the stomach. Dr William Beaumont saved St. Martin's life. The wound, however, left an opening in St. Martin's stomach that never healed completely. Beaumont realized that by looking through the opening in St. Martin's abdomen, he could observe what was happening inside the stomach.

Beaumont observed that food changed chemically inside the stomach. He hypothesized that chemical reactions in the stomach broke down foods into smaller particles. Beaumont removed liquid from St. Martin's stomach and analyzed it. The stomach liquid contained an acid that played a role in the breakdown of foods into simpler substances.

Functions of the Digestive System

Beaumont's observations helped scientists understand the role of the stomach in the digestive system. The digestive system has three main functions. First, it breaks down food into molecules the body can use. Then, the molecules are absorbed into the blood and carried throughout the body. Finally, wastes are eliminated from the body.

As food moves through the digestive system, digestion, absorption, and elimination occur one after the other in an efficient, continuous process.

Which organs does food pass through after leaving the mouth?

The Digestive System

The picture shows the organs of the digestive system, which is 9 meters long from beginning to end.

This means it is close to 30 feet long!

Chemicals produced by the body break food into their smaller chemical building blocks. For example, the starch in bread is broken down into individual sugar molecules.

Chemical Digestion

Foods are physically broken down into smaller pieces. Mechanical digestion occurs when you bite into a sandwich and chew it into small pieces.

Mechanical Digestion

Digestion
The process by which your body breaks down foods into small nutrient molecules.

Multiple Choice

What is digestion?

• The process by which your body breaks down foods into small nutrient molecules

• The process by which nutrient molecules pass through the wall of your digestive system and into your blood

Multiple Choice

What kind of digestion occurs when you bite into a sandwich?

• Mechanical Digestion

• Chemical Digestion

Multiple Choice

What kind of digestion occurs when the starch in bread is broken down into individual sugar molecules?

• Mechanical Digestion

• Chemical Digestion

Absorption and Elimination

After your food is digested, the molecules are ready to be transported throughout your body. Absorption is the process by which nutrient molecules pass through the wall of your digestive system into your blood. Materials that are not absorbed, such as fiber, are eliminated from the body as wastes.

Multiple Choice

What is absorption?

• The process by which your body breaks down foods into small nutrient molecules

• The process by which nutrient molecules pass through the wall of your digestive system and into your blood

Multiple Choice

What is the process by which your body gets rid of materials that are not absorbed?

• Absorption

• Elimination

• Mechanical Digestion

• Chemical Digestion

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Multiple Choice

Digestion begins...

• In your stomach
• In your mouth
• In your small intestine
• In your large intestine

Multiple Choice

On average, how long does the process of digestion take?

• 5 hours
• 12-24 hours
• 1 week
• 1 month

Multiple Choice

What does our body receive from food?

• organs
• saliva
• nutrients
• cells

Multiple Choice

Why are nutrients MOST important to our body?

• Gives us energy
• Makes us happy
• Makes us full
• None of the above

Multiple Choice

Muscular tube that connects the mouth to the stomach

• Epiglottis
• Trachea
• Stomach
• Esophagus

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Multiple Choice

Which organ absorbs any remaining water and turns food into waste?

• Large Intestine
• Small Intestine
• Liver
• Pancreas

Multiple Choice

Where does the food the body can't use get sent to?

• Stomach
• Small Intestine
• Gall Bladder
• Large Intestine

Multiple Choice

Which organ sends nutrients from food to the rest of the cells in our bodies?

• Stomach
• Small Intestine
• Large Intestine
• All of the above

Multiple Choice

Which is NOT a function of the Digestive System?

• To rid the body of solid waste
• Absorb nutrients for energy & growth
• Break down nutrients from food
• Pump blood around the body

Multiple Choice

What does the stomach do?

• Sends signals to your brain
• Adds digestive juices to the food
• Protects your lungs
• Pumps blood to your heart

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Multiple Choice

What breaks down food in stomach?

• acid 
• salivary glands
• movement 
• time

Multiple Choice

What does the mouth do?

• Break down the food to make it easier to swallow
• Slows down jaws
• Nothing
• Neither

Multiple Choice

How long is an adult’s small intestine?

• A) 30 miles
• B) 30 inches
• C) 22 feet
• D) 17 yards

Multiple Choice

When they reach the stomach, mashed-up food particles mix with:

• A) Guava juice
• B) Gastric juices
• C) Mucous
• D) Bile

Multiple Choice

Which example best shows structures that make up the digestive system in the human body?  

• A) A heart, blood, vessels
•  B) nose, trachea, lungs
• C) brain, spinal cord, nerves
• D) esophagus, stomach, intestines 

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Multiple Choice

Why do we need to break apart the food we eat?

• So it can fit in our stomach

• So our bodies can use the nutrients

• So liquids can be separated from solids

• So our bodies enzymes can have something to do

Multiple Choice

Place the following events in sequence: A) Food enters your large intestine; B) Food enters your small intestine; C) Food enters your esophagus

• A, B, C

• C, B, A

• C, A, B

• B, A, C

Multiple Choice

Waste foods are separated from solids and liquids in the __________________.

• small intestine

• large intestine

• liver

• stomach

Multiple Choice

What does your tongue do?

• It produces insulin.

• It produces bile.

• nothing

• It moves food around your mouth.

Multiple Choice

The body system that breaks down food into tiny pieces so that the body’s cells can use it for energy.

• Digestive System
• Skeletal System
• Nervous System
• Circulatory System

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Multiple Choice

A fluid in the mouth that helps digest food.

• Nutrients
• Absorb
• Digestion
• Saliva 

Multiple Choice

The process by which the body breaks down food so that it can be used for energy.

• Digestion
• Respiration
• Circulation 
• Absorb

Multiple Choice

To take in matter or energy.

• Digestion
• Nutrients
• Absorb
• Mouth

Multiple Choice

How long is an adult’s small intestine?

• 22 feet

• 30 inches

• 30 miles

• 17 feet

Multiple Choice

The digestive process starts in the:

• Stomach

• Esophagus

• Mouth

• Bathroom

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Multiple Choice

The liver’s role is to:

• Mash up food

• Turn water into food

• Help the stomach

• Remove harmful substances from the blood

Multiple Choice

When they reach the stomach, mashed-up food particles mix with:

• Guava juice

• Gastric juices

• Mucus

• Bile

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Multiple Choice

What does the digestive system do?

• Breaks down and handles food

• Pumps blood throughout the body

• Helps you breathe

• Helps your arms and legs move

Multiple Choice

Your food can spend up to this long in the small intestine:

• 4 minutes

• 4 months

• 4 seconds

• 4 hours

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Multiple Choice

What tube moves food from the back of your throat to the stomach?

• Epiglottis

• Esophagus

• Feeding tube

• Pharynx

Multiple Choice

The large intestine measures about:

• 1 foot long

• 10 feet long

• 5 feet long

• 100 feet long

Poll

THE DIGESTIVE SYSTEM IS.....

• EASY TO DIGEST.. LIKE APPLESAUCE!

• EASY TO DIGEST... LIKE SPAGHETTI NOODLES

• DIGESTING LIKE... PEANUTBUTTER

• DIGESTING LIKE... ROCKS