The digestive system

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Lesson 1

• OB6 Identify and locate the major parts of the digestive system including: the mouth, oesophagus, stomach, liver, pancreas, small intestine, and know their functions

Lesson 2

• OB7 Identify molars, premolars, canines and incisors, and describe their functions

Lesson 3

• OB8 Investigate the action of amylase on starch; identify: the substrate, product and enzyme

Lesson 1

What happens during digestion? The organs involved in the process

The Cell

What happens in digestion?

5 Stages of Digestion

• Ingestion• Digestion• Absorption• Assimilation• Egestion• http://www.learning-is-fun.co.uk/bi

ology/nutrition.html

• In• Down• Around• And• Eject

• Ingestion: Food taken into mouth

• Digestion: Food broken down by teeth and digestive enzymes

• Absorption: into bloodstream

• Egestion: Undigested material egested through anus

Large Molecule

Enzymes

ABSORPTION

An Overview

Importance of digestion

• Digestion: Break down of large food molecules into small molecules

• Types of digestion:– Physical– Chemical

The Mouth

• Function: Chew food to break down into smaller molecules– Teeth

Teeth

• Four types of teeth:1. Incisors2. Canines3. Pre – Molars4. Molars

Incisors

Canines

Premolar

Molar

Biting and

Cutting

Incisor

Grasping and

Tearing

Canine

Grinding and

Crushing

Pre - Molar

Grinding and

Crushing

Molar

Digestive Organs• Oesophagus

• Stomach

• Small Intestines

• Large Intestines

• Pancreas

• Liver

Name some digestive organs…..

The parts of the digestive system

• The mouth

• The oesophagus

• The stomach

• The small intestine

• The large intestine

The Oesophagus

• Function: to take food from mouth to stomach by muscular action called peristalsis

= Food particle

Oesophagus

Stomach

• Store food• Mix food with juice• Kill bacteria in food

Small Intestine

• Complete digestion of food• Absorb digested food into bloodstream

Large Intestine

• To absorb water from the waste food, solidifying the faeces

Liver

• The liver makes bile• Function of bile

– to dissolve fats – neutralise acid from

the stomach

The Pancreas

• Sends a liquid into the small intestine– digestive enzymes to

digest starch, proteins and fats

Lesson 3

Practical Class

Enzymes

• Biological catalysts that break down food

To investigate the action of amylase on starch

Starch sol.

Starch sol. & amalyse

A B

A B

37° 10mins

Iodine

The Action of Amylase on Starch

Use the set up above to investigate!

End Products of digestion

• Carbohydrate

• Protein

• Fats

• Simple sugars

• Amino acids

• Fatty acids and glycerol

Assessment

Students must attempt all questions!

Question 1

• (a) What are the functions of the digestive system

• (b) Name the chemicals that digest food

Question 2

• Name the part labelled A to E.

• Name the parts labelled F and G

Question 4

• Follow the food as it passes through the digestive tract and explain the process of digestion.

• Identify type of teeth marked A,B and C.

• Give the function of each.

A B C

Chapter Assessment

1. An enzyme is a biological _____________

2) Taking food into the mouth is known as ____________

3) Explain the difference between physical and chemical digestion. Give one example of each type.

4) What is the name given to the process whereby food is pushed along the alimentary canal

5) List the two major functions of the large intestine ?.

6) The oesophagus carries the food from the ________ to the __________

Bibliography• http://www.chemistry.wustl.edu/~edudev/LabTutorials/

HIV/images/enzyme.jpg• www.calalumni.ch/images/ 031025_basel_meeting/...• http://science.waltermack.com/smack/yr8biol/

digestion2.gif• http://medicalimages.allrefer.com/large/gelatin-capsule-

in-stomach.jpg• http://www.becomehealthynow.com/images/organs/

digestive/sm_intestine.jpg• http://www.cindys-friends.com/images/pic_intestine.jpg• http://laxmi.nuc.ucla.edu:8000/NM-Mediabook/figures/

GI/liver/liver_ant.gif

Bibliography• http://gxs.home.texas.net/work_samples/pancreasf/

pancreas.gif• http://bimari-jankari.mla.iitk.ac.in/html/b_digest.htm• http://files2.turbosquid.com/Preview/

Content_on_8_10_2005_06_45_00/mr_fastsss_teeth_various_poses.pnge9a81577-7091-47bc-992e-835a2061e3dcLarge.jpg

• www.ivansanford.com/il_bloodstream.html• Clip art• Shea Mullally: Less stress more success – science• Michael O’ Callaghan: Exploring Science: Edco