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Digestion and Disease

Mahi Tuatahi

  1. Name a machine that transforms gravitational potential energy to electrical energy
  2. What is the chemical element, K, and what food is a good source of it?
  3. What vitamin is used in building eyes?

Ngā Whāinga Ako

The Digestive System

You Are A Tube!

The digestive system is essentially a very long tube, going from your mouth to your rectum!

What is digestion?

Insoluble: adjective - means that it cannot dissolve in water (e.g. oil)

Task: Label the digestive sytem

Why so many parts?

As food moves through your digestive system each part helps do different things:

Swallowing food without choking

How do we get food down our esophagus to our stomachs without choking?


This is the process of contraction and relaxation of the muscles in the esophagus to propel the food down.

The muscles above the food contract to help push the food down, and the relax for the next lump of food or mouthful.

In conjunction with this, various organs in the mouth move to block airways so that you do not choke.

Task: Digestive Disease Pamphlet (in pairs)

Include: Part(s) of the digestive system where it occurs, what the condition does, how to avoid/treat the disease

Gastroesophageal Reflux Disease, gallstones, celiac disease, Chron’s disease, uclerative colitis

In The Mouth

Digestion begins in the mouth where food is broken down by the teeth. This is called mechanical breakdown.

The small parts are mixed with saliva and swallowed.

Saliva contains enzymes that start to chemically break down some of the starch and fats in the food.

Enzymes are biological catalysts that speed up chemical reactions.


Amylase and Starch

Amylase (enzyme) breaks the long starch chains into glucose molecules.

Think about the nutrients in bread and how how long can you hold a piece of bread in your mouth?

Task: Match these up

Digestive EnzymeWhat it does
CarbohydraseBreaks fat into glycerol and fatty acids
LipaseBreaks protein into amino acids
ProteaseBreaks carbohydrate into sugar molecules

Down to the Stomach

Food then passes the epiglottis, a flat of skin and cartilage that prevents food from entering the trachea (air tube).

The food is then moved down the oesophagus with the help of wave-like contractions, a process called the peristaltic wave.

The Stomach

The stomach is a muscular sac with a variety o functions.

masticate: verb - to chew (food)

After the Stomach

chyme: thick, semifluid partially digested mass of food


Small Intestine



Villi Continued

Large Intestine

Task: Complete these sentences about digestion.

  1. Digestion is the process of breaking ? molecules of food into ? molecules of food.
  2. The ? molecules that we start with are ? which means they ? dissolve in water.
  3. The ? molecules produced by digestion are ? which means they ? dissolve in water.

Words: can, small, insoluble, soluble, large, large, small, cannot