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© Boardworks Ltd 2003 Teacher’s Notes A slide contains teacher’s notes wherever this icon is displayed - To access these notes go to ‘Notes Page View’ (PowerPoint 97) or ‘Normal View’ (PowerPoint 2000). Notes Page View Normal View Flash Files A flash file has been embedded into the PowerPoint slide wherever this icon is displayed – These files are not editable. © Boardworks Ltd 2003 Energy release When something burns, heat and light energy is released. This process will produce energy if there are 2 main ingredients. combustion FUEL + OXYGEN Carbon dioxide + Water + If these two and heat are all present then the fuel and oxygen will react. This reaction is called COMBUSTION. © Boardworks Ltd 2003 The Heart The heart is made of very special muscle, CARDIAC muscle. It must keep beating all the time for the rest of a persons life! If you tried to do the same action repeatedly (like the heart) your muscles would get tired and, after a while, they would stop working. For example if you clench and unclench your hand continuously, it will get tired, and may even start to cramp. © Boardworks Ltd 2003 The blood system This is the system which carries the dissolved food and oxygen around the body. This includes the heart and the lungs. © Boardworks Ltd 2003 Blood cells provide oxygen and the plasma in the blood carries dissolved food to ALL the cells in the body. © Boardworks Ltd 2003 Inhalation (When we breathe in we inhale) © Boardworks Ltd 2003 What type of fuel is required by the body? The body changes food into a form which can be carried around the body. This substance is called GLUCOSE. Glucose contains energy. When glucose reacts with oxygen a LOT of energy is produced. Some of this energy is released as heat while the rest is used by the cells. The cells do NOT catch fire. © Boardworks Ltd 2003 What is respiration? RESPIRATION is the process which releases energy from food. This is NOT the same as breathing. We can now write out the full equation for RESPIRATION. FOOD (GLUCOSE) from digestive system + OXYGEN from breathing system CARBON DIOXIDE waste product exhaled + WATER waste product exhaled + ENERGY USEFUL! Combustion is different because it is NOT a controlled reaction. Respiration IS a controlled reaction which SLOWLY releases energy from food in the CELLS. © Boardworks Ltd 2003 How does oxygen get into our body? The body separates the process of breathing in and breathing out. Breathing in is one process and is known as inhalation . When we inhale we breathe in air, taking oxygen with it into our lungs. Breathing out is a separate process and is known as exhalation . When we exhale we breathe out the contents of our lungs, pushing out waste gases like carbon dioxide © Boardworks Ltd 2003 Exhalation (When we breathe out we exhale) © Boardworks Ltd 2003 The Alveoli Oxygen makes its way into thousands of special air sacs collectively called the ALVEOLI. The outside of the alveoli is covered with tiny blood vessels. © Boardworks Ltd 2003 The Alveolus One of these alveoli is called the ALVEOLUS. This is where the oxygen is transferred into the blood and carbon dioxide moves out of the blood. If all these alveoli flattened and spread out onto the floor, they would cover an area the size of a tennis court! © Boardworks Ltd 2003 Different types of activity What happens to the man’s pulse rate when running? The pulse is faster: • Blood is pumped around the body faster. • Oxygen and glucose reach muscle cells more quickly. • Energy is used up faster. While sleeping • Blood is pumped around the body more slowly. • Oxygen and glucose reach body cells more slowly. • Energy is used up at a slower rate. © Boardworks Ltd 2003 Aerobic Respiration When the body can supply the cells with the oxygen and food that they need, We say it is performing AEROBIC respiration. The equation for this is: Glucose + oxygen Carbon dioxide + water + ENERGY Anaerobic Respiration When the body CANNOT supply the cells with the oxygen and food that they need, then the body must perform anaerobic respiration. The release of energy WITHOUT oxygen: Glucose Lactic acid + a little energy © Boardworks Ltd 2003 Not enough oxygen When anaerobic respiration takes place, the lactic acid soaks the muscle cells and prevents the muscle cell from doing its job. This causes fatigue and/or cramp. After the activity has been completed people pant and breathe heavily. This happens because oxygen is required to get rid of the build up of lactic acid. © Boardworks Ltd 2003 Comparing inhaled and exhaled air What are the big differences between inhaled and exhaled air? How could you test for these? Inhaled Air Exhaled Air Nitrogen (78%) Oxygen (20.71%) Carbon Dioxide (0.1%) Other Nitrogen (75.5%) Oxygen (14.6%) Carbon Dioxide (4%) Other There is another difference…… …… water vapour. © Boardworks Ltd 2003