KS3+DIGESTION

Describe the digestive system and its function.
 * The digestive system** is one of our organ systems(organ system: groups of organs that carry out a particular function), in which humans and other mammals exchange substances with the environment. Digestion is the process of breaking down the food into nutrients that can be taken into and used by the body. It takes place in the alimentary canal and organs such as the liver and pancreas. The digestion process involves both physical and chemical breakdown and thus creating waste to be eliminated.

The table shows its main tissues and organs, and their functions: [|Main tissues and organs in the digestive system and their functions from BBC Bitesize]
 * ~ Part(s) ||~ Function ||
 * Pancreas and salivary glands || Produce digestive juices ||
 * Stomach || Digests food ||
 * Liver || Produces __ bile __ ||
 * Small intestine || Digest and absorb soluble food ||
 * Large intestine || Absorbs __ water __ from undigested food, producing faeces ||

Identify and place the organs of the digestive system - mouth, oesophagus/gullet, stomach, small intestine, large intestine Identify where and how digestion begins. Model a simple version of the process within the complete alimentary canal Identify organs which excrete waste products **Task 1**: Check the nutrition contents of each dish and describe the digestion process using animation below. [|Digestion animation from kitses.com] [|Process of digestion] from springfield.uk.net [|Label the digestive system] from springfield.uk.net =**Homework 27th Oct. 2014:**= Find the definitions of keywords in the above table. Go to discovery puzzle maker and create a criss cross puzzle using keywords from digestive system. Save it in a word format and bring the print to the next lesson.
 * Keywords**
 * Alimentary canal || the passage for the digestion of food in animals, including the gullet, stomach and intestines. ||
 * absorption ||  ||
 * anus ||  ||
 * digestion ||  ||
 * dissolve ||  ||
 * enzyme ||  ||
 * fat ||  ||
 * gullet/oesophagus || the tube connecting the mouth to the stomach. It is also called the oesophagus. ||
 * large intestine ||  ||
 * liver ||  ||
 * small intestine ||  ||
 * peristalsis || A wave of muscular contraction. ||
 * catalysts || a substance that speeds up a chemical reaction without beig changed or used up in the reaction. ||
 * ducts || tubes ||
 * rectum || The faeces are stored in the rectum before being released through the anus in a process called egestion. ||

Appreciate that enzymes (amylase, protease, lipase) exist and help in the breakdown of specific foods. [|Enzymes digestion] from intel education [|How do enzymes work] from springfield.uk.net [|Which enzyme quiz] from springfield.uk.net [|Digestion summary] from springfield.uk.net Homework Complete the questions below after reading the text 2 page 37- 43. 3. How does saliva help in digesting food?
 * Enzymes || Where can you find it? || What does it break down? ||
 * Amylase || Mouth(salivary glands) || It breaks down starch molecules in the food into sugar molecules. ||
 * Pepsin || Stomach wall(gastric glands) || It breaks down protein. Proteins are broken down into amino acids in small intestine. ||
 * Bile || made in Liver then stored in Gall bladder mixed with food in Duodenum || It helps to the breakdown of fat into small droplets. Fats are broken down into fatty acids and glycerol in small intestine. ||
 * pancreas juice (protease, carbohydrase, lipase) || Pancreas || It contains enzymes that digest proteins, fats and carbohydrates. ||
 * carbohydrase ||  || an enzyme that digests carbohydrate. ||
 * protease ||  || an enzyme that digests protein. ||
 * lipase ||  || an enzyme that digests fat ||
 * Hydrochloric acid(It helps pepsin work) || Stomach wall(gastric glands) || It kills bacteria in the food. ||
 * Hydrochloric acid(It helps pepsin work) || Stomach wall(gastric glands) || It kills bacteria in the food. ||

4. What is peristalsis?

5. What does hydrochloric acid do?

6. Where is bile made and what does it do?

7. What are proteins, fats and carbohydrates broken down into?

8. Where are the digested foods absorbed?

9. What happens to undigested food in the large intestine?

11. What type of enzyme is produced in the mouth and in the stomach?

12. What type of enzyme does bile help?

13. Where does bile come from?

14. Which organ of the digestive system produces all three types of enzyme?

15. Why do small droplets of fat get broken down by enzymes more quickly than large droplets?

[|Digestion video] from fact of life website =Task 2:= Describe the journey of a cheese sandwich. = For your 'Food tests' lab report = Aim: To test the presence of nutrients in the food. Diagrams: Methods: Results table : Conclusion: Evaluation: Is it a fair test?