DIGESTION AND EXCRETION DIGESTION When you eat foodssuch

DIGESTION AND EXCRETION

DIGESTION � � When you eat foods—such as bread, meat, and vegetables—they are not in a form that the body can use. Food and drink must be changed into smaller molecules of nutrients before they can be absorbed into the blood and carried to cells throughout the body. Digestion is the process by which food and drink are broken down into their smallest parts so the body can use them. Your body gets the Energy it needs from food through a process called metabolism cells Digestion smaller form absorbed energy

ACTIVITY 1 Click on the following link to watch a Digestive System animation. Check your understanding by completing the quiz found under the animation. http: //highered. mcgraw-hill. com/sites/0072495855/student_view 0/chapter 26/animation__organs_of_digestion. html

METABOLISM � Metabolism is a collection of chemical reactions that takes place in the body's cells. � Metabolism converts the fuel in the food we eat into the energy needed to power everything we do, from moving to thinking to growing. energy converts growing food reactions

CELLULAR RESPIRATION � � Cellular respiration is the set of metabolic reactions It allows organisms to release the energy stored in food This process occurs in every cell in your body Cellular respiration can be summarised by the following chemical equation: Food + oxygen water + carbon dioxide + energy Food + oxygen release water + carbon dioxide + energy metabolic cell

EXCRETION � � � Sugars, fats, and proteins can all be turned into energy for the cells to use. The cell breaks them down into small pieces, but not every piece can be used. The process of making energy also makes other chemicals that your body cannot use. The chemicals that are left over from or created during this process can be harmful if there are too many of them in your body. Your body gets rid of these harmful chemicals through the excretory system. harmful chemicals breaks energy excretory

THE EXCRETORY SYSTEM The excretory system is your body's way of removing harmful wastes from your blood. � It is made up of your skin, your kidneys, and your lungs. � Each of these organs removes a different kind of waste from your body. � blood kidneys lungs wastes skin different

LUNGS Your lungs remove harmful gases. � Carbon Dioxide is a waste gas that is made when your cells make energy. � The carbon dioxide is carried by your blood to your lungs. � In your lungs, carbon dioxide is released from your blood. � Oxygen takes its place. � Carbon dioxide is removed from your lungs every time you exhale. � Carbon dioxide lungs blood gases Oxygen exhale

KIDNEYS � � � Your kidneys filter liquid waste out of your blood. Their most important job is to remove a chemical called urea from your blood. Urea can be quite harmful to your body. It is made when your body breaks down water from meat, beans, nuts, and other foods. The kidneys remove unwanted minerals, proteins, and urea from your blood. It forms a liquid called urine that is stored in your bladder before it is removed from your body. minerals harmful urine water urea proteins

ACTIVITY 1 Work through the following interactive to learn more about the kidneys. Complete the quiz to check your understanding. � http: //www. kidney. org. au/flash/kidney_animation/kidneys. html#intro

SKIN water skin dead salt � The final organ in the excretory system is your skin. � It removes dead cells, salt, and unused water from your body through sweating.