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Boardworks IGCSE Biology

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Presentation on theme: "Boardworks IGCSE Biology"— Presentation transcript:

1 Boardworks IGCSE Biology
Breathing Breathing

2 Boardworks IGCSE Biology
The exchange of gases Boardworks IGCSE Biology Breathing Aerobic respiration is the process of releasing energy through the oxidation of glucose molecules: carbon dioxide glucose + oxygen + water ( energy) + Oxygen is breathed into the lungs and is transported in blood. Carbon dioxide and water are formed as waste products in cells. They can be excreted when we breathe out. Teacher notes It might be necessary to remind students that respiration is not the same as breathing. Respiration is the chemical process that takes place in cells to release energy from glucose, using oxygen. Breathing is the action of getting air into lungs (inhalation) and expelling it from the lungs (exhalation). Most of the organs of the respiratory system are found in the thorax. The respiratory system carries out gas exchange. It is made up of the lungs, intercostal muscles, diaphragm and airways. 2

3 Parts of the respiratory system
Boardworks IGCSE Biology Breathing

4 The mechanism of ventilation
Boardworks IGCSE Biology Breathing

5 Exercise, respiration and ventilation
Boardworks IGCSE Biology Breathing Energy is used up by the active muscles during exercise. The rate of respiration must therefore increase to supply enough energy to the muscles. This means that more oxygen must be breathed in and more carbon dioxide breathed out. During exercise, why does: Teacher notes During exercise, the heart rate increases to pump the blood quicker around the body to the working muscle cells. This will increase the rate of transfer of oxygen and glucose, and the removal of waste, including carbon dioxide. The rate and depth of breathing increases to increase the rate of gas exchange. The arteries dilate to accommodate the increased blood flow to the muscles. Blood flow can increase to 35 times its normal volume during exercise. During exercise, blood is diverted away from systems that are not involved in activity, for example, the digestive system. Photo credit: © Sebastian Kaulitzki, 2012 Shutterstock.com the heart rate increase the rate and depth of breathing increase the arteries supplying the muscles dilate?

6 Running and breathing rates
Boardworks IGCSE Biology Breathing Teacher notes Students could design and carry out their own experiments to investigate the effects of exercise and recovery on breathing rate. Breathing rate can me measured manually or with appropriate sensors and data loggers. Students should observe appropriate safety measures and you should make sure you are aware of any students with illnesses such as asthma. 6

7 Boardworks IGCSE Biology
Carbon dioxide Boardworks IGCSE Biology Breathing The brain can detect the level of carbon dioxide in cells. When the level of carbon dioxide increases during exercise, the brain must coordinate ways to prevent the levels reaching toxic levels. One way the brain deals with a build up of carbon dioxide during exercise is by increasing the rate of breathing. Teacher notes Symptoms of carbon dioxide toxicity include drowsiness, reduced vision, dizziness, headache and an increased heart rate and blood pressure. This increases the rate of gas exchange and the removal of carbon dioxide from the lungs.


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