Digestion,science Form 2

FAT WATER

CARBOHYDRATE

FOOD CLASSES PROTEIN

VITAMINS, MINERALS, & ROUGHAGE

THEME : MANAGEMENT AND CONTINUITY OF LIFE LEARNING AREA : NUTRITION

Learning Objectives : Understanding the digestive system of man Learning outcome: A student is able to: explain what digestion is identify the parts of the digestive system describe the flow of food particles in the alimentary canal state the functions of the organs in the digestive system describe the process of digestion in the alimentary canal list the end products of digestion of carbohydrate, protein and fats

MOUTH

LIVER

OESOPHAGUS

SHORTMO

GALLBLADDER STOMACH PANCREAS

LARGE INTESTINE

SMALL INTESTINE

END PRODU

The food in the mouth are cut up and grind into small pieces by the teeth. These food pieces would provide a bigger surface area for the enzyme. Food is mixed with saliva. Digestive action : Starch → maltose (sugar)

Peristalsis which is caused by the muscles in the oesophagus push the food into the stomach The movement is supported by the slippery 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 juice which consists of some enzymes and hydrochloric acid. The functions of hydrochloric acid are: - It provides an acidic medium for the enzymes e.g. renin and pepsin to digest protein in food. - It also kills microorganisms such as bacteria which enters the stomach. The half digested food will be sent to duodenum for the next process.

Parts of the digestive system

Digestive juice

Duodenum

Bile (alkaline) produced by the liver and kept in the gall bladder Pancraetic juice (alkaline)

Enzymes

Pancreatic amylase Protease Lipase

Digestive action Further information

Fat → tiny particles (A process which breaks down the fat into tiny particles by the bile which is called emulsification) Maltose → glucose Peptone → amino acid Fat → 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 easily The bile and the pancreatic juices (alkaline) neutralises the acid from the stomach

MORE

Parts of the digestive system Small intestine (6 metres long)

Digestive juice

Enzymes

Digestive action

Further information

Intestinal juices from wall of the small intestine (alkaline)

Erepsin Several other enzymes to digest the complex sugar

Peptone → amino acid Complex sugar → simple sugar Maltose → glucose Sukrase → glucose + fructose Lactase → 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 Large intestine

Digestive juice

Enzymes Digestive action

Further information

None

None

Absorption of water and waste is left.

None

LET US HAVE A LOOK AT AN INTERACTIVE VIEW OF WHAT HAPPEN IN OUR DIGESTIVE 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

TASK SHEET 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:________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________

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.

WHAT IS DIGESTION?

THE FLOW OF FOOD PARTICLES IN THE ALIMENTARY CANAL THE PROCESS OF DIGESTION IN THE ALIMENTARY CANAL

PARTS OF DIGESTIVE SYSTEM

SUMMARY

THE FUNCTIONS OF THE ORGANS IN THE DIGESTIVE SYSTEM

THE END PRODUCTS OF DIGESTION OF CARBOHYDRATE, PROTEIN AND FATS

PROJECT Title: Model of the human digestive system Aim: 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