http://www.lifedynamix.com/articles/files/iStockKidNutrition.jpghttp://www.lifedynamix.com/articles/files/iStockKidNutrition.jpg Digestive System
Functions of the digestive system • Ingestion • Mechanical processing • Digestion • Secretion • Absorption • Excretion http://greenfield.fortunecity.com/rattler/46/upali4.htm http://www.mydr.com.au/default.asp?Section=gastrointestinalhealth
The Digestive process can be broken down into 4 parts: • Ingestion – taking in of nutrients • Digestion – breakdown of complex molecules into smaller components by enzymes • Absorption- transport of digested nutrients to the tissue of the body • Egestion – removal of waste food material from the body
Ingestion: eating • Physical digestion begins in the mouth, where food is chewed and formed into a bolus (greek word for ball) by the tongue.
In the mouth: physical and chemical digestion starts! • Teeth: physical breakdown of food into smaller pieces. • Saliva: chemical breakdown of starch, lubricates food so it can be swallowed and makes food taste…good or bad
Saliva: • Contains the enzyme AMYLASE that breaks down starch into simple sugars • Lubricates food • Dissolves food particles • Activates the taste buds (Scientific American March 2001)
Test your tastebuds Conduct a simple scientific experiment to find out whether you have a supertaster tongue or not. All you need is: • Food colouring • Cotton buds • Reinforcement rings for hole-punched paper • Magnifying glass This is what you need to do: • Using a cotton bud, swab some food colouring on to the tip of your tongue • Place a reinforcement ring on your tongue • Count the pink dots within the reinforcement ring. This may be easier with a magnifying glass • The pink dots are your fungiform papillae. They don't take up the food colouring. These papillae are the tiny bumps on your tongue that house your taste buds. The more papillae you have, the more taste buds you have and the more sensitive to taste you are. On average, non-tasters have fewer than 15 papillae in that area, while supertasters have over 30.