Learning objectives

• Identify the structure of the organs within the digestive system

• Oesophagus, stomach, duodenum, ileum, colon

• Accessory organs including the liver, pancreas and salivary glands.

Parts of the Digestive System

• Mouth

• Esophagus

• Stomach

• Small Intestine

• Large Intestine

• Liver (A)

• Gallbladder (B)

• Pancreas (C)​

What is Digestion?

Digestion is the mechanical and chemical breakdown of food into smaller particles and molecules that your body can absorb and use.

Breaking Food Down

Mechanical Digestion – Involves the tearing, crushing and mashing of food. Example: When you take a bite and chew it with your teeth or when your muscles of the stomach contract and relax.

Chemical Digestion – When chemicals called enzymes help break down larger molecules into smaller molecules.

What is the path food takes through your body?

1) Mouth – Food is shredded by the teeth and mixed with saliva. Saliva breaks down starches into simple sugars and softens and moistens the food. The tongue pushes the food, now called bolis, down the esophagus.

What is the path food takes to get through your body?

2) Esophagus – The muscles in the esophagus push the bolis down into the stomach while its walls, lined with mucus, makes it easier for the food to slide down.

What is the path food takes to get through your body?

3) Stomach – There is a strong acid called Hydrochloric acid  that dissolves the food.The digestive juices (enzymes and acid) that break protein causing it to now turn into a mush called the bolis. (chyme).  

What is the path food takes to get through your body?

4) Small Intestine – Most of digestion occurs here. Also reabsorption of the broken down macronutrients get reabsorbed in the blood. Nutrients passes into the bloodstream through the villi, which line the small intestine walls, and are transported throughout the body.

What is the path food takes to get through your body?

5) Large Intestine – Materials that cannot be absorbed pass into the large intestine. The large intestine absorbs water and stores waste until it can be eliminated from the body.

The liver makes a digestive juice called bile that helps digest fats and some vitamins. Bile ducts carry bile from your liver to your gallbladder for storage, or to the small intestine for use.

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​Liver

The gallbladder stores bile, a thick liquid that's produced by the liver to help us digest fat. When you eat, the gallbladder's thin, muscular lining squeezes bile into the small intestine through the main bile duct.

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​Gallbladder

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During digestion, your pancreas makes pancreatic juices called enzymes. These enzymes break down sugars, fats, and starches. Your pancreas also helps your digestive system by making hormones.

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​Pancreas

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• ​Crohn's Disease.

• Gallstones

• ​IBS

Some Pathologies