CHAPTER 10 Respiration in Humans

1. CHAPTER 10 Respiration in Humans

2. Chapter 10 Respiration in Humans 10.1 Why Do Living Things Respire? 10.2 Studying Respiration 10.3 Gas Exchange in Humans 10.4 Breathing Mechanisms in Humans 10.5 Effects of Tobacco Smoke on Human Health

3. Why Do Living Things Respire? 10.1 • Learning Outcomes • After this section, you should be able to: • understand that living things respire to release the energy locked up in food molecules; • define aerobic respiration and anaerobic respiration; • state the equation, in words and in symbols, for aerobic respiration and anaerobic respiration in humans; and • describe the effect of lactic acid in muscles during exercise.

4. Why Do Living Things Respire? 10.1 Why respire? • Living organisms respire because they need energy to sustain life. • Energy that is needed for organisms to move, grow, excrete and reproduce, is obtained through the consumption of food. • To use the energy available in food, living things need to break down the food molecules through a process called ____________________. • The oxidation of food molecules to produce energy is called ____________________.

5. energy + O2 C6H12O6 CO2 H2O 6 + 6 6 + oxygen glucose water carbon dioxide Why Do Living Things Respire? 10.1 What is aerobic respiration? • It is the breakdown of food molecules in the ____________________. • It results in the production of __________________ and it gives off ____________________and _______________as waste products. • The chemical equation for aerobic respiration:

6. energy + C3H6O3 2 Why Do Living Things Respire? 10.1 What is anaerobic respiration? • It is the breakdown of food molecules in the ____________________. • It releases __________________than aerobic respiration. • The chemical equation for anaerobic respiration in humans: C6H12O6 lactic acid glucose (energy produced is less than in aerobic respiration)

7. Why Do Living Things Respire? 10.1 What happens during exercise and why? • Muscles ___________________to enable movement. • Respiratory rate and heart rate increase to enable more oxygen to reach the muscles. • If the increased oxygen intake is not able to meet the oxygen demand, an __________________ results and ___________takes place to provide the energy required. • Anaerobic respiration results in the accumulation of ____________________in the muscle cells. • Lactic acid accumulation can cause _______________and muscular pains.

8. Chapter 10 Respiration in Humans 10.1 Why Do Living Things Respire? 10.2 Studying Respiration 10.3 Gas Exchange in Humans 10.4 Breathing Mechanisms in Humans 10.5 Effects of Tobacco Smoke on Human Health

9. Studying Respiration 10.2 • Learning Outcomes • After this section, you should be able to: • describe simple experiments that show what the products of respiration are.

10. Studying Respiration 10.2 Carbon dioxide is a product of respiration • The potassium hydroxide in flask A removes carbon dioxide from the air entering flask B. • The limewater in flask B should not turn chalky. • The air entering flask C does not contain carbon dioxide. Hence, any carbon dioxide detected in flask D would be due to respiration by the snails. A B C D potassium hydroxide solution limewater snails limewater

11. Studying Respiration 10.2 Carbon dioxide is a product of respiration • The glucose solution that is used was first boiled and cooled to remove the dissolved oxygen from the solution. • Due to the limited oxygen available to the yeast, the yeast undergoes anaerobic respiration. • If carbon dioxide is released during the anaerobic respiration of yeast, the limewater will turn chalky. glucose and yeast suspension limewater

12. vacuum flask pea seeds in antiseptic solution cotton wool plug thermometer Studying Respiration 10.2 Heat is a product of respiration • The vacuum flask prevents heat from escaping and entering the area where the seeds are germinating. • The cotton wool plug allows gaseous exchange between the seeds and the environment. • The antiseptic solution prevents the growth of microorganisms like bacteria. • If heat is produced during respiration, the thermometer would register a temperature higher than the surrounding temperature.

13. Chapter 10 Respiration in Humans 10.1 Why Do Living Things Respire? 10.2 Studying Respiration 10.3 Gas Exchange in Humans 10.4 Breathing Mechanisms in Humans 10.5 Effects of Tobacco Smoke on Human Health

14. Gas Exchange in Humans 10.3 • Learning Outcomes • After this section, you should be able to: • identify the parts in the human gaseous exchange system; • describe the role of the alveoli in gaseous exchange; and • describe the removal of carbon dioxide from the lungs.

15. Gas Exchange in Humans 10.3 Why the need for a respiratory system? • Humans are large organisms that are made up of millions of cells. • We have a _______________________________, unlike unicellular microorganisms. • Therefore, we need a special system of organs for gaseous exchange between the environment and the cells in our bodies. • This mechanism of exchange is called external respiration and it involves a process called _________________________.

16. Gas Exchange in Humans 10.3 Human gas exchange system nasal passage The fringe of hair and the mucous layer on the walls of the _______________ trap dust and foreign particles. pharynx larynx As the air passes through the air passages, it is warmed and moistened.

17. Gas Exchange in Humans 10.3 Human gas exchange system nasal passage The _________________is supported by C-shaped rings of cartilage that ensure that the trachea is always open. pharynx larynx _________ C-shaped ring of cartilage _________ Transverse section of a trachea

18. Gas Exchange in Humans 10.3 On the inner walls of the trachea and bronchi are: gland cell • ____________, and • ____________________ mucus produced by gland cell Gland cells _____________ that trap dust particles and bacteria in the air that is channelled to the lungs. Ciliated cells have __________that sweep the trapped particles and bacteria up the bronchi and trachea, into the ___________________. cilia ciliated cell

19. Gas Exchange in Humans 10.3 Human gas exchange system The lungs lie in the pleural cavity. Within the lungs, the bronchial tubes divide repeatedly to form __________________. Bronchioles end in cluster of _______________ called ____________________. nasal passage pharynx larynx trachea bronchus _____________ __________ cluster of _________ URL

20. Gas Exchange in Humans 10.3 The alveoli The alveoli are the ______ _____________________. The numerous alveoli in the lungs increase the surface area for gaseous exchange.

21. blood vessel from heart blood vessel to heart air in and out capillary wall alveolar wall capillary network thin film of water Gas Exchange in Humans 10.3 The alveoli The alveoli are well-supplied with _________________ to enable the efficient exchange of gases. The alveolar surface is coated with a ___________________. This allows gases to dissolve in it. The wall of each alveolus is only _____________________. It is supplied by _______________that are also only one cell thick.

22. inhaled oxygen oxygenated blood (transported to the heart and enters the systemic circulation) carbon dioxide to be exhaled deoxygenated blood (carbon dioxide rich) O2 Gas Exchange in Humans 10.3 Gas exchange in the alveolus alveolus CO2 capillary URL

23. High O2 concentration + 4 Hb Hb O2 O2 O2 O2 O2 Low O2 concentration Gas Exchange in Humans 10.3 How oxygen is transported Haemoglobin Oxygen molecules bind to ________________ (Hb) in red blood cells to form __________________________. + O2 - O2 Oxyhaemoglobin oxygen haemoglobin oxyhaemoglobin

24. Gas Exchange in Humans 10.3 How carbon dioxide is transported Carbon dioxide molecules from respiring cells enter the red blood cells in the blood stream. There, the carbon dioxide molecules react with water to form ____________________. This reaction is catalysed by an enzyme found in the red blood cells – ____________________. The carbonic acid is then converted into ______________________ which will diffuse out of the red blood cells and into the blood plasma. Most of the carbon dioxide is transported as hydrogen carbonate ions in the _________________________.

25. Chapter 10 Respiration in Humans 10.1 Why Do Living Things Respire? 10.2 Studying Respiration 10.3 Gas Exchange in Humans 10.4 Breathing Mechanisms in Humans 10.5 Effects of Tobacco Smoke on Human Health

26. 10.4 Breathing Mechanisms in Humans • Learning Outcomes • After this section, you should be able to: • describe the role of the cilia, diaphragm, ribs and intercostal muscles in breathing.

27. ________ 10.4 Breathing Mechanisms in Humans The ______support the chest wall. Two sets of muscles can be found between the ribs: nasal passage pharynx • ____________________, and • ____________________. larynx trachea bronchus bronchiole lung cluster of alveoli

28. 10.4 Breathing Mechanisms in Humans Intercostal muscles Vertebral column The intercostal muscles move the rib cage up and down during breathing. Sternum Rib Intercostal muscles Left lung inside the rib cage

29. rib 10.4 Breathing Mechanisms in Humans The ______________is a dome-shaped sheet of muscle and elastic tissue that contracts and relaxes to change the volumeof the ____________. nasal passage pharynx larynx trachea bronchus bronchiole lung cluster of alveoli URL ____________

30. air is sucked in External intercostal muscles contract and internal intercostal muscles relax  rib cage is raised __________________and __________________ 2 3 Thoracic volume ___________, so air is drawn into the lungs 1 Diaphragm __________ and flattens down. 10.4 Breathing Mechanisms in Humans Inspiration spinal column

31. air is expelled out External intercostal muscles relax and internal intercostal muscles contract  rib cage moves _________________and ____________________ 2 3 Thoracic volume __________, lungs are compressed and air is forced out of the lungs 1 Diaphragm ____________and arches upwards. 10.4 Breathing Mechanisms in Humans Expiration spinal column

32. Just like how the handle of a pail is moved upwards Position during inspiration External intercostal muscles contract, raising the ribs upwards Internal intercostal muscles relax, allowing the ribcage to move outwards Position during expiration 10.4 Breathing Mechanisms in Humans Model showing the movement of the ribs during breathing

33. high Number of breaths per minute low 10.4 Breathing Mechanisms in Humans What is the stimulus for breathing? Which curve, A, B or C, represents what happens when pure oxygen is supplied for breathing? Answer: A 90% O2 + 10% CO2 B 21% O2 + 0.03% CO2 C 100% O2 Time Carbon dioxide is the stimulus for breathing.

34. Chapter 10 Respiration in Humans 10.1 Why Do Living Things Respire? 10.2 Studying Respiration 10.3 Gas Exchange in Humans 10.4 Breathing Mechanisms in Humans 10.5 Effects of Tobacco Smoke on Human Health

35. Effects of Tobacco Smoke on Human Health 10.5 • Learning Outcomes • After this section, you should be able to: • describe the effects of the major toxic components of tobacco smoke on human health.

36. Nicotine Carbon monoxide Irritants (e.g. formaldehyde, hydrogen cyanide) Tar Effects of Tobacco Smoke on Human Health 10.5 • addictive • makes blood clot more easily • increases the risk of heart diseases • decreases the ability of red blood cells to transport oxygen • increases the rate at which fats are deposited on the inner arterial walls • increases the risk of artherosclerosis • paralyse the cilia lining in air passages • increase the risk of chronic bronchitis and emphysema • carcinogenic • paralyses the cilia lining in air passages • reduces the efficiency of gaseous exchange

37. Effects of Tobacco Smoke on Human Health 10.5 Chronic bronchitis • In chronic bronchitis, • the epithelium lining the airways is inflamed, • there is excessive mucus secretion, and • the cilia lining the airways are paralysed. • Symptoms: • Breathing difficulties due to blocked airways • Persistent cough (body’s response to clear the blocked airways) over secretion of mucus cilia paralysed and unable to remove mucus

38. Effects of Tobacco Smoke on Human Health 10.5 Emphysema • In emphysema, • the partition walls of alveoli break down due to violent coughs. (This reduces the surface area available for gaseous exchange.) • The lungs lose their elasticity and become inflated with air. • Symptoms • Breathing difficulties • Wheezing partition walls between alveoli healthy lungs damaged partition walls diseased lungs

39. Chapter 10 Respiration in Humans

40. Chapter 10 Respiration in Humans The URLs are valid as at 15 October 2012.