Form Group 3CForm Group 3C

1212thth January 2007 January 2007

WHAT IS DIGESTION?WHAT IS DIGESTION?

Digestion ?Digestion ?

• Process of breaking Process of breaking down large insoluble down large insoluble molecules (e.g starch, molecules (e.g starch, proteins, fat) into proteins, fat) into smaller soluble smaller soluble molecules.molecules.

Digestive System?Digestive System?

• An organ system, is An organ system, is made of a group of made of a group of organs all working organs all working together.together.

• Each organ has a Each organ has a particular function particular function and only by working and only by working together will they together will they get the job done.get the job done.

What do you really know?What do you really know?

Digestion ProcessDigestion Process

1. Mouth1. Mouth

In the In the mouthmouth the food is broken into small the food is broken into small pieces and mixed with pieces and mixed with salivasaliva..

Salivary glandSalivary gland

2. Gullet or oesophagus2. Gullet or oesophagus

oesophagusoesophagusPart of the tube Part of the tube responsible responsible for carry the food from for carry the food from the mouth to the the mouth to the stomach.stomach.

3. Stomach3. Stomach

• Is a muscular bagIs a muscular bag

that produces gastricthat produces gastric

juices.juices.

• It includes dilute It includes dilute hydrochloric acid and hydrochloric acid and enzymes that we call enzymes that we call proteasesproteases..

4. Gall Bladder or the bile4. Gall Bladder or the bile

Does not contain any enzymes but it Does not contain any enzymes but it breaks down the fats into very small breaks down the fats into very small droplets, giving a larger space to the droplets, giving a larger space to the fat enzymes called fat enzymes called lipaseslipases can work can work in the small intestine.in the small intestine.

Bile is produced Bile is produced by the liver.by the liver.

5. Pancreas5. Pancreas

The pancreas The pancreas produces the produces the pancreatic pancreatic juice.juice.

66. Small and Larger IntestineSmall and Larger Intestine

• Most food products Most food products are absorbed in the are absorbed in the small intestine. small intestine.

• The large intestine is The large intestine is responsible for responsible for absorptionabsorption of water of water and excretion of solid and excretion of solid waste materialwaste material.

SmallSmall intestine intestine

LargerLarger

intestineintestine

rectumrectum

Digestion happens in 2 ways.

The shape of the The shape of the food must be food must be physically changed physically changed so that it can fit in so that it can fit in the digestive the digestive system. system.

This allows useful This allows useful chemicals to be chemicals to be released and dissolve released and dissolve in the blood. To be in the blood. To be broken down broken down chemically, the bonds chemically, the bonds must be broken.must be broken.

PhysicalPhysical ChemicalChemical

Enzymes...Enzymes...

AmylaseAmylase

ProteaseProtease

Lipase, Protease and Amylase.Lipase, Protease and Amylase.

Class Notes...Class Notes...

• Digestion involves breaking down Digestion involves breaking down large insoluble food molecules ( like large insoluble food molecules ( like starch, protein and fats) into smaller starch, protein and fats) into smaller soluble molecules.soluble molecules.

• Find out what to write about the Find out what to write about the function of which organ in the function of which organ in the digestive system...digestive system...

(mouth,gullet, stomach, bile, pancreas, (mouth,gullet, stomach, bile, pancreas, smaller and larger intestine).smaller and larger intestine).