Chemical and physical changes in the Digestive system

Chemical and physical changes in the Digestive system

by Susie Haas

​Digestion is the breaking down of foods into a form that can be absorbed by the body.

Multiple Choice

Where does digestion begin?

• Stomach

• Mouth

• Small Intestine

• Large intestine

​Digestion begins in the mouth with our teeth and saliva.

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​Physical changes happen to our food when our teeth crush and grind our food into smaller pieces.

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​Chemical changes happen to our food when the enzymes in saliva react with the food to break down our food even more.

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Multiple Choice

What type of change occurs in the mouth?

• Physical change

• Chemical change

• Both types of change occurs

• There is no change to our food in the mouth.

​The tube leading from the mouth

to the stomach is called the esophagus.

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There is a safety valve in your throat called the

epiglottis that protects you from getting food

in your lungs. It slams shut when you swallow

to force food down the esophagus instead of

the trachea.

Your uvula is the body part that hangs down in your throat.

Right behind it is your gag reflex. If something is too big to fit down your throat you will gag to bring it back up.​

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Multiple Choice

What it the safety mechanism that keeps food from going down the wrong tube?

• Epiglottis

• Uvula

• Esophagus

• Trachea

​Peristalsis

​Smooth muscle contractions that move food down your esophagus to your stomach,

​ This also occurs in your intestines to move food further along in the digestive system.

​Stomach

​When food enters the stomach, muscle contractions smash the food up even more.

​At the same time, acid is released from

the stomach lining to chemically break down

​the food.

Multiple Choice

What type of change occurs to our food in the stomach?

• Chemical change

• Physical change

• Chemical and physical change

• No change occurs to our foody

​Before the food can enter the intestines it must be in liquid form. The molecules must be small enough to be absorbed in the small intestine so they can be delivered to our cells.

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Multiple Choice

Which body system delivers the nutrients to our cells?

• Digestive

• Endocrine

• Muscular

• Circulatory

​Helper organs

​Salivary glands secrete saliva that

​breaks down starches into sugar.

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​Liver produces bile that breaks up fat.

​Pancreas produces sodium bicarbonate that neutralizes the acid from the stomach

​Gall bladder stores the bile

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Multiple Choice

Which helper organ keeps our intestines from getting burned by acids?

• Salivary glands

• Liver

• Pancreas

• Gall bladder

​Duodenum

​The first 6 inches of the small intestine where more chemicals are added to complete the breakdown of our food.

​The liver produces bile that is stored in our gall bladder to be delivered to the duodenum to break up the fat molecules.

​The pancreas produces sodium bicarbonate to neutralize the acid before it moves further into the small intestine.

​The food is now in a form the body can absorb.

Multiple Choice

What kind of change happens to our food in the small intestines?

• Physical change

• Chemical change

• Both types of change 

• There is no change to our food in the small intestines

​Small Intestine

​Inside the small intestines are lined with structures called villi that help with absorption of nutrients. The small intestines are about 23 feet long to allow the maximum amount of absorption.

​When the food leave the small intestines, most of the nutrients have been absorbed and what is left is mostly chemicals and substance that we do not need.

Multiple Choice

What structures in the small intestines make it easier to absorb nutrients?

• Villi

• Gall bladder

• Liver

• Duodenum

​Appendix

​Vestigial organ that can sometimes get infected and burst.

​No known function of the appendix.

​Large intestine

​When the leftover substance moves into the large intestine the water is reabsorbed into the body over a period of several hours.

​There is a physical change in our large intestine from liquid to a solid before it is excreted by our body.

Multiple Choice

What kind of change happens to our food in the large intestine?

• Physical change

• Chemical Change

• Both types of changes occur

• No change occurs to our food here.