FOOD CLASSES

CARBOHYDRATE

FAT

WATER

VITAMINS, MINERALS, & ROUGHAGE

PROTEIN

THEME :

MANAGEMENT AND

CONTINUITY OF LIFE

LEARNING AREA :

NUTRITION

Learning Objectives : Understanding the digestive

system of manLearning outcome: A student is able to:

explain what digestion isidentify the parts of the digestive systemdescribe the flow of food particles in the alimentary canalstate the functions of the organs in the digestive systemdescribe the process of digestion in the alimentary canallist the end products of digestion of carbohydrate, protein and fats

MOUTH

OESOPHAGUSLIVER

STOMACH

GALLBLADDER

PANCREAS SMALL INTESTINE

LARGE INTESTINE

END PRODUCT

SHORTMOVIE

The food in the mouth are cut up The food in the mouth are cut up and grind into small pieces by the and grind into small pieces by the teeth. These food pieces would teeth. These food pieces would provide a bigger surface area for provide a bigger surface area for the enzyme. Food is mixed with the enzyme. Food is mixed with saliva.saliva.

Digestive action :Digestive action :Starch → maltose (sugar)Starch → maltose (sugar)

Peristalsis which is caused by the Peristalsis which is caused by the muscles in the oesophagus push muscles in the oesophagus push the food into the stomachthe food into the stomachThe movement is supported by the The movement is supported by the slippery mucusslippery mucus

1. The liver produces bile which is an alkaline and kept in the gall bladder - Bile will digest fat to tiny particles

-This process is called emulsification

2. Pancreas produces pancreatic juice which is an alkaline and it has 3 enzymes that can digest :

- Maltose → glucose- Peptone → amino acid- Fat → fatty acid & glycerol

Stomach has gastric Stomach has gastric juicejuice whichwhich consists consists of some enzymes and hydrochloric acid. of some enzymes and hydrochloric acid.

The functions of hydrochloric acid are:The functions of hydrochloric acid are:

The half digested food will be sent to The half digested food will be sent to duodenum for the next process.duodenum for the next process.

- It provides an acidic medium for the - It provides an acidic medium for the enzymes e.g. renin and pepsin to digest enzymes e.g. renin and pepsin to digest protein in food.protein in food.- It also kills microorganisms such as bacteria - It also kills microorganisms such as bacteria which enters the stomach.which enters the stomach.

Parts of the digestive system

Digestive juice

Enzymes Digestive action Further information

Duodenum Bile (alkaline) produced by the liver and kept in the gall bladderPancraetic juice (alkaline)

Pancreatic amylaseProteaseLipase

Fat → tiny particles(A process which breaks down the fat into tiny particles by the bile which is called emulsification)Maltose → glucosePeptone → amino acidFat → fatty acid & glycerol

The result of this process is the increased of the surface area of fat particles. This would help the enzyme to react on the food more easilyThe bile and the pancreatic juices (alkaline) neutralises the acid from the stomach

MORE

Small intestine(6 metres long)

Intestinal juices from wall of the small intestine (alkaline)

ErepsinSeveral other enzymes to digest the complex sugar

Peptone → amino acidComplex sugar → simple sugarMaltose → glucoseSukrase → glucose + fructoseLactase → glucose

Digested food is absorbed by tiny villi which are found in the small intestinal wall into the blood stream

Parts of the digestive system

Digestive juice

Enzymes Digestive action Further information

Parts of the digestive system

Digestive juice

Enzymes Digestive action

Further information

Large intestine

None None None Absorption of water and waste is left.

LET US HAVE A LET US HAVE A LOOK AT AN LOOK AT AN INTERACTIVE INTERACTIVE

VIEW OF WHAT VIEW OF WHAT HAPPEN IN OUR HAPPEN IN OUR

DIGESTIVE DIGESTIVE TRACT ! ! !TRACT ! ! !

THE END PRODUCTS OF DIGESTION OF CARBOHYDRATE, PROTEIN AND FAT

CARBOHYDRATE → SIMPLE SUGAR → GLUCOSE,

( MALTOSE) FRUCTOSE,

GALACTOSE

PROTEIN → PEPTONE → AMINO ACID

FAT → TINY FATTY PARTICLES → FATTY ACID &

GLYCEROL

Procedure: 1 Observe a human digestive model/chart. Observe the various parts which make up the human digestive system.2 Know the various parts of the human digestive and label the diagram provided: teeth, tongue, mouth, salivary gland, oesophagus, stomach, duodenum, small intestine, large , intestine, liver, pancreas, gal/ bladder, bile duct, anus

Discuss the functions of the various parts of the digestive system.

Working Method:______________________________________________________________________________________________________________________________________________________________________________________________________

TASK SHEET

Observation: State the sequence of the organs which are passed by the food.

____________________________________________________________________________________________________

Questions:1 What is digestion?

__________________________________________________2 What is the advantage of the muscular bag shaped stomach?__________________________________________________3 What is the purpose of having a long small intestine?____________________________________________________________________________________________________4 How does food move along the alimentary canal?__________________________________________________5 How is the digested food absorb?__________________________________________________Conclusion: The digestive system consists of several ____________ which helps to _____________ food to simpler particles.

SUMMARY

WHAT IS DIGESTION? PARTS OF DIGESTIVE SYSTEM

THE FUNCTIONS OF THE ORGANS IN THE DIGESTIVE SYSTEM

THE FLOW OF FOOD PARTICLES IN THE ALIMENTARY CANAL

THE PROCESS OF DIGESTION IN THE ALIMENTARY CANAL

THE END PRODUCTS OF DIGESTION OF CARBOHYDRATE, PROTEIN AND FATS

PROJECT

Title: Model of the human digestive systemAim: To enhance the students’ knowledge about the digestive system of man. To prepare items for the Science week .Learning outcome: Pupils will be more knowledgeable about the digestive system of a human being. Materials: Plasticine, plywood, manila card, colour papers, magic ink pens supplied by the Science department. Time Allocation: 1 week after finishing the topic concern.Workgroup: 4/5 pupils

Suggested Procedures:

Refer to any Science text book or the internet and look up for a diagram showing a human being’s digestive system.

Study the diagram carefully and make a model of the digestive system.

Your model must be as accurate proportionally to the actual organs of the digestive system.

You can add colour or whatever else that you can think of in order to enhance your model.

Your model must be properly labelled.

The functions of the various organs must also be available.

Extra marks will be given for tidiness.

THE END