At the end of this unit you should:

2. At the end of this unit you should: • Be able to list the parts of the respiratory system and explain their function. • Know where in the body the lungs are located and what protects them. • Know what gases are exchanged at the lungs. • Know how gas exchange occurs. • Be able to distinguish between how we breathe in and how we breathe out. • Know the difference between the breath we take in and the breath we let out. • Be able to describe factors that affect the respiratory system.

3. alveoli asthma bronchiole bronchitis bronchus carbon dioxide diaphragm emphysema exhaling gas exchange inhaling intercostal muscles lung capacity lungs oxygen respiration ribcage ribs thoracic cavity trachea

4. LIGHTBULB QUESTION We breathe to take in oxygen so the cells can release energy and push out carbon dioxide from the lungs, as too much carbon dioxide lowers the blood’s pH levels, making it more acidic.

5. (a) Copy Table 03.04.01 and give the information needed.

6. (b) Give a function for each part of the respiratory system. Nose: Allows gases in and out of the body Mouth: Allows gases in and out of the body Trachea: A tube that allows gases in and out of the lungs Bronchus: Allows gases in and out of the lungs Bronchiole: Allows gases in and out of the lungs Alveoli: Allows an exchange of gases to happen in the lungs Diaphragm: A muscle that contracts and relaxes, which moves gases in and out of the lungs Ribs: Protect the lungs Intercostal muscle: Moves the ribcage up and down

7. (a) What is the name given to the part of the respiratory system that allows the exchange of gases to happen? Alveoli.

8. (b) Describe what the inside of the lung looks like. The trachea branches off into two tubes that enter the lungs. Both lungs have the same make-up on the inside. The bronchus is a tube that allows gases to flow through. This tube gets smaller in diameter and is called the bronchiole. At the end of each bronchiole there are millions of tiny sacs called alveoli. These are surrounded by a capillary network.

9. Investigation 03.04.01: Finding out your lung capacity Diagram: Equipment: An empty transparent plastic bottle (1 or 2 litres), a bendy straw or narrow tubing, a large deep bowl, water, masking tape and marker, a measuring cup/graduated cylinder. Instructions: Using the equipment as listed, devise an investigation to find your lung capacity. Carry out the investigation three times and record your results. Compare your results with your classmates’ results.

10. 1. Suggest why you were asked to carry out the investigation more than once. • To make sure the result was accurate and avoid any possible errors.

11. 2. Do you think there will be any variation within the class results? Support your answer with an explanation. • Yes, as individuals will have different lung capacities.

12. 3. Make a list of factors that you think might affect lung capacity. • Body size, gender, whether the person is a smoker or non-smoker, physical fitness levels, having any disorders of the respiratory system, e.g. asthma or bronchitis.

13. (a) How do the oxygen molecules reach the body cells? Oxygen molecules reach the body cells via the blood, which is part of the circulatory system. (b) Suggest why the oxygen is needed there. As the muscles are working, they are using energy. This energy needs to be in constant supply. The oxygen molecules need to get from the lungs to the muscles to allow the cells to release energy that they can use.

14. (c) What would happen to a person’s body if the heart was unable to work properly? They would not be able to supply cells with oxygen and therefore would not be able to release the energy needed at the muscles to allow them to work. Therefore the body would work at a slower rate and get tired more quickly. The body would not be able to remove carbon dioxide from the blood and so would lower the pH level of the blood.

15. (d) There is an urgency or hurry of oxygen getting to the muscle cells. Will the need for oxygen to the muscles change if you are playing a game of hurling, for example? Explain your answer using as many of your new keywords as possible. Yes, the need for oxygen to the muscles would change if you were playing a game of hurling, as in hurling the muscles are working at a faster rate compared to carrying out normal daily activities. The body needs oxygen in order to release energy by respiration and to get rid of carbon dioxide from our blood, which occurs during the exchange of gases in the alveoli of the lungs.

16. Investigation 03.04.02: How do different levels of exercise affect breathing rate? Equipment: You and a partner, results table, stopwatch. Instructions: Design and carry out an investigation to find out how different levels of exercise affect your breathing rate.

17. 1. Predict what your results will be with different levels of exercise. Breathing rate will increase the higher the level of exercise.

18. 2. Why is it important to measure your breathing rate at rest before you start the investigation? It is important to measure breathing rate at rest before the investigation starts so breathing rate at rest can be compared to breathing rate immediately following exercise.

19. 3. What would you expect to happen your breathing rate immediately after exercise? Support your answer with an explanation. • Breathing rate would have increased. As oxygen is needed by the muscles, the lungs are working harder to bring oxygen to them.

20. 4. What happens when your exercise level is low? • The demand for oxygen is low as the muscles are not working and therefore do not need the supply of oxygen to release energy.

21. 5. Suggest a possible source of error during this investigation. • Student might count seconds rather than the actual number of times they see the crease of their elbow move up and down./Students might count every time they see the crease of the elbow move rather than counting the up and down movement as one.

22. Copy and Complete In this unit I learned that the respiratory system is made up of the mouth, nose, windpipe, lungs, bronchus bronchiole and air sacs. The two muscles involved in the system are the diaphragm and the intercostal muscles. The lungs are protected by the ribcage and they are in our chest area. At the air sacs, which are at the end of the small tube called the bronchiole, there is an exchange of gases: oxygen from the air goes from the air sac into the blood; carbondioxide goes from the blood into the air sac to be pushed out of the body.

23. Copy and Complete When we breathe in, our ribcage moves up and outwards, and the diaphragm moves down, making more room in the chest area, which allows more air to come in. When we breathe out, the ribsmove down and in and the diaphragm moves up into a dome shape. This makes the room inside the chest area smaller, which causes the air to be pushed out. The oxygen molecules that we take in travel around the body in the blood.

24. 1. Identify the parts of the respiratory system numbered in this diagram. Nose Mouth Larynx Trachea Bronchus Bronchiole Alveoli Throat Rib Intercostal muscle Diaphragm

25. 2. Describe the journey an oxygen molecule takes after it enters the nose. It travels down the trachea and into the left or right bronchus. It then travels into the bronchiole and along into the alveoli. From here it crosses over the capillaries and attaches to the haemoglobin on the red blood cell. It is then transported to cells in the body to allow respiration to take place.

26. 3. Give another name for a) the windpipe; b) the chest area. a) trachea; b) thoracic cavity.

27. 4. Using a diagram, describe what happens at the air sacs or alveoli.

28. 5. Copy and complete the flow chart comparing what happens when you breathe in and out. Use the phrases in the list to help you. ribs move up and out ribs move down and in diaphragm moves down diaphragm moves into a dome shape volume in chest cavity increases volume in chest cavity decreases

29. 6. How does the composition of blood change as it travels from the heart through the capillaries at the lungs? Can you explain why these changes occur? Composition: From the heart going to the lungs the blood is carrying a high amount of carbon dioxide, low amounts of oxygen and other substances. At the lungs the capillaries exchange the carbon dioxide for oxygen molecules. The blood returning to the heart now has a small amount of carbon dioxide and a large amount of oxygen. These changes occur because the carbon dioxide is acidic and if there are high amounts of carbon dioxide in the blood it changes the pH levels of the blood. The brain detects these changes and tells the lungs to breathe out. There is an exchange of gases at the air sacs in the lungs. When a carbon dioxide molecule leaves the lungs an oxygen molecule enters.

30. 7. What do you think might happen to your breathing rate if you were standing still and then started to run really fast? It would rapidly increase.