2Boardworks KS3 Science 2008 Respiration Releasing energy
3How is digested food used by the body? Boardworks KS3 Science 2008RespirationThe body needs a constant supply of energy which comes from digested food.Glucose, from digested carbohydrates, is an important substance that contains stored chemical energy.When glucose reacts with oxygen, a lot of energy is released.In the body’s cells, glucose and oxygen react to releaseenergy. Some of this is released as heat and the rest is used by the cells.What is the release of energy from glucose called?
4Boardworks KS3 Science 2008 Respiration What is respiration?Boardworks KS3 Science 2008RespirationRespiration is the process that the body uses to release energy from digested food (glucose):carbondioxideglucose+oxygen+water( energy)+from the digestive systemfrom the respiratory systemwaste product (exhaled)waste product (exhaled)Teacher notesThis could be a good place to make sure pupils understand that respiration is not the same as breathing and ventilation.This type of respiration is called aerobic respiration because energy is released in the presence of oxygen.How do the glucose and oxygen needed for aerobic respiration get to the all the body’s cells?
5Testing for the products of respiration Boardworks KS3 Science 2008RespirationTeacher notesIf the limewater turns cloudy this indicates that carbon dioxide is present.If students carry out the experiment with limewater it’s important that the safety issues involved with the activity are made clear.
6How do cells get oxygen and glucose? Boardworks KS3 Science 2008Respiration
7The equation for aerobic respiration Boardworks KS3 Science 2008Respiration
8Respiration and combustion Boardworks KS3 Science 2008RespirationBurning is the reaction between a fuel and oxygen. This reaction is called combustion:fuel+oxygencarbon dioxide+waterDuring combustion, heat and light energy are released and carbon dioxide and water are also produced, so combustion is similar to respiration.The difference between combustion and respiration is that combustion is not a controlled reaction. Respiration is a controlled reaction that slowly releases energy from food in the body’s cells and the cells do not catch fire!
9Respiration and combustion Boardworks KS3 Science 2008Respiration
10The circulatory system Boardworks KS3 Science 2008RespirationThe circulatory system
11Boardworks KS3 Science 2008 Respiration CirculationBoardworks KS3 Science 2008RespirationThe dissolved food and oxygen needed for respiration are carried around the body by the circulatory system.The circulatory system includes the blood, blood vessels, the heart and the lungs.Teacher notesRespiration Worksheet 1 accompanies this slide.Which part of the circulatory system actually carries dissolved food and oxygen to the body’s cells?
13Boardworks KS3 Science 2008 Respiration Your beating heartBoardworks KS3 Science 2008RespirationThe heart is made of very special muscle called cardiac muscle.This is because it has to keep beating for the whole of a person’s life!If you tried to do the same action repeatedly (like the heart does), your muscles would get tired and, after a while, stop working.For example, if you keep clenching and unclenching your hand, it will get tired and may even start to get cramp.Why is it important for respiration that the heart keeps beating?
14Ideas about circulation Boardworks KS3 Science 2008Respiration
15Boardworks KS3 Science 2008 Respiration Measuring pulseBoardworks KS3 Science 2008RespirationThe heart pumps blood around the body in the blood vessels. Each time it pumps it causes the blood vessels to throb. This is called a pulse.To take your pulse:Hold out one hand with the palm facing up.2. Put the index and middle fingers of your other hand together.3. Press these fingers lightly on the underside of the other wrist, just under the thumb bone.Photo credit: Jupiterimages CorporationTeacher notesStudents could be reminded here not to use their thumb to take a pulse rate, as the thumb itself has a pulse.Taking a pulse in this way is a technique is thought to have been first described by Galen.
16Different types of activity Boardworks KS3 Science 2008RespirationWhat happens to the pulse while someone is running?During exercise, the pulse rises. This causes blood to be pumped around the body more quickly, which increases the amount of oxygen and glucose that can reach muscle cells.What happens to the pulse while someone is sleeping?Photo credit: Jupiterimages CorporationTeacher notesRespiration worksheet 2 accompanies this slide. This worksheet involves a simple practical and drawing a graph of results. The practical could be carried out in a sports hall or outside of the school building.During sleep, the pulse falls. This causes blood to be pumped around the body more slowly. This means that oxygen and glucose take longer to reach muscle cells.
17Boardworks KS3 Science 2008 Respiration The breathing system
18Boardworks KS3 Science 2008 Respiration What is breathing?Boardworks KS3 Science 2008RespirationThe breathing system is used by the body to get the oxygen needed for respiration.It is also used to get rid of one of the waste products of respiration: the gas, carbon dioxide.Breathing in and breathing out are separate processes in the body.Breathing in is called inhalation. When you inhale, you breathe air, including oxygen, into your lungs.Breathing out is called exhalation. When you exhale you breathe out the contents of your lungs and get rid of the waste gas carbon dioxide.
19Inhalation and exhalation Boardworks KS3 Science 2008Respiration
20Boardworks KS3 Science 2008 Respiration The alveoliBoardworks KS3 Science 2008Respiration
21Boardworks KS3 Science 2008 Respiration Gas exchangeBoardworks KS3 Science 2008Respiration
22Comparing inhaled and exhaled air Boardworks KS3 Science 2008RespirationWhat are the differences between inhaled and exhaled air?Inhaled AirExhaled AirOxygen: 21%Oxygen: 16%Carbon dioxide: %Carbon dioxide: 4%Water vapour: small amountWater vapour: large amountWhat are the main differences?How could you test for the differences between inhaled and exhaled air?
24Anaerobic respiration Boardworks KS3 Science 2008RespirationAnaerobic respirationTeacher notesThis section on anaerobic respiration could be linked across the curriculum with PE.
25Aerobic and anaerobic respiration Boardworks KS3 Science 2008RespirationWhen the body is able to supply its cells with the oxygen and glucose that they need, it carries out aerobic respiration.oxygencarbondioxideglucose+water( energy)When the body cannot supply the cells with the oxygen needed to break down glucose, then it has to carry out anaerobic respiration. Energy is released without oxygen:Teachers notesThis may be a good place to make sure the students understand that anaerobic respiration does not replace aerobic respiration. Only cells that require more energy, such as muscle cells, will carry out anaerobic respiration if there’s not enough oxygen present.lactic acidglucoseenergy+
26Boardworks KS3 Science 2008 Respiration Not enough oxygen!Boardworks KS3 Science 2008Respiration+glucoselactic acidenergyWhen anaerobic respiration takes place, lactic acid is also produced.Lactic acid builds up in the muscle cells and prevents the muscles doing their job. This is thought to cause fatigue and sometimes cramp.Photo credit: Jupiterimages CorporationAfter exercise the body needs to remove the lactic acid before it causes damage to cells.
27Boardworks KS3 Science 2008 Respiration Oxygen debtBoardworks KS3 Science 2008RespirationLactic acid is broken down by oxygen.oxygenwaterlactic acidcarbon dioxide+After activity that has lead to anaerobic respiration, the person involved breathes heavily and their heart rate remains high to supply the body with the oxygen it needs.Photo credit: Jupiterimages CorporationTeachers notesRespiration Worksheet 3 accompanies this slide.The amount of oxygen needed to remove all the lactic acid after exercise is called an oxygen debt.
28How does running affect your pulse? Boardworks KS3 Science 2008Respiration
31Boardworks KS3 Science 2008 Respiration GlossaryBoardworks KS3 Science 2008Respirationaerobic – The type of respiration that occurs with oxygen.alveoli – Tiny air sacs in the lungs where gas exchange takes place.anaerobic – The type of respiration that occurs without oxygen.combustion – The reaction between fuel and oxygen.exhalation – The process of breathing out.glucose – A type of sugar that the body releases energy from during respiration.inhalation – The process of breathing in.oxygen debt – The amount of oxygen needed to remove lactic acid after exercise.respiration – The process that the body uses to release energy from digested food.