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BIOLOGY FORM 4 CHAPTER 7 - RESPIRATION PART 1

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BIOLOGY FORM 4 CHAPTER 7 - RESPIRATION PART 1

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BIOLOGY FORM 4 CHAPTER 7 - RESPIRATION PART 1

  1. 1. BIOLOGY FORM 4 CHAPTER 7 RESPIRATION PART 1
  2. 2. Objectives 7.1 Understanding the respiratory processes in energy production 7.2 Analysing the respiratory structure and breathing mechanism in human and animal 7.3 Understanding the concept of gaseous exchange across the respiratory surfaces and transport of gases in human 7.4 Understanding the regulatory mechanism in respiration 7.5 Realising the importance of maintaining a healthy respiratory system 7.6 Understanding respiration in plants
  3. 3. 7.1 Understanding the respiratory processes in energy production
  4. 4. The respiratory gases • are:
  5. 5. cells need to: obtain O2 WHY? eliminate CO2 WHY?
  6. 6. cells need to: obtain O2 to produce ATP eliminate CO2 to prevent toxic effects
  7. 7. What is respiration?? Process of obtaining oxygen and delivering it to the cells for cellular respiration and removing carbon dioxide produced by cells
  8. 8. Respiration External Respiration (Breathing) Internal Respiration (Cellular respiration) Aerobic Respiration Anaerobic Respiration 2 stages 2 types
  9. 9. External respiration (Breathing) • The exchange of respiratory gases (oxygen and carbon dioxide) between the body and the environment
  10. 10. Internal respiration ( Cellular Respiration) • A metabolic process • which occurs in cells, • involves oxidation of organic molecules(food) • to produce energy (in the form of ATP) • Controlled by enzymes Two types : 1. Aerobic respiration 2. Anaerobic respiration
  11. 11. The main substrate to produce energy is GLUCOSE
  12. 12. Fuels are used in sequence Muscle Glucose is stored here as glycogen and is used when the body is working harder. 1. CARBOHYDRATES 2. FATS 3. PROTEINS Liver Here some of the glucose is stored as glycogen and used to maintain blood sugar levels. Used when the carbohydrates are exhausted. Are first converted to glycerol and fatty acids Used when carbohydrates and fats have been used up as during prolonged starvation
  13. 13. ENERGY
  14. 14. How does body convert energy stored in food  energy for body use?
  15. 15. Through Cellular Respiration  Cellular Respiration is the oxidation of food (glucose) with the release of energy in living cells 2 Types of Cellular Respiration: Aerobic and Anaerobic respiration
  16. 16. Aerobic respiration • Require oxygen • Glucose is completely oxidised • to produce 36 - 38 molecules of ATP / 2898 kJ energy (high energy) • Takes place in the cytoplasm and mitochondria C6H12O6 + 6O2 6CO2 + 6H2O + Energy (2898 kJ)
  17. 17. Anaerobic respiration • Without oxygen • Glucose is not completely broken down • Releases only 2 ATP (low energy) • Takes place in the cytoplasm • Eg. In human muscles, yeast, microbes in mud Yeast: Glucose  Carbon dioxide + ethanol + 210 kJ energy Muscle: Glucose  Lactic acid + 150 kJ energy
  18. 18. Some microbes living in the mud… low oxygen level … Respire ananerobically!
  19. 19. • Respiration without oxygen.
  20. 20. YYeEaAsSTt!
  21. 21. Anaerobic respiration in yeast •Yeast normally respires aerobically •Anaerobic respiration in yeast produces ethanol, carbon dioxide and energy
  22. 22. IN YEAST • Anaerobic respiration in yeast also known as fermentation C6H12O6 2CO2 + 2C2H5OH + Energy(210kJ) ethanol Zymase • Ethanol can be used in wine & beer production • CO2 released causes the dough to rise (to make bread)
  23. 23. Alcoholic Fermentation C6H12O6  2C2H5OH + 2CO2 + energy glucose ethanol carbon dioxide • Occurs in yeast cells.
  24. 24. Dough rising 36 The yeast is mixed with the dough After 1 hour in a warm place the dough has risen as a result of the carbon dioxide produced by the yeast
  25. 25. Anaerobic Respiration Glucose (with baker’s yeast)  Carbon dioxide + ethanol + little energy (210kJ) The ‘holes’ in the bread are made by the carbon dioxide bubbles. This gives the bread a ‘light’ texture
  26. 26. Anaerobic respiration in humans! Highly intensive exercise Glucose  Lactic acid + energy
  27. 27. Anaerobic Respiration in the Muscles 1. Vigorous muscle movement  increase rate of aerobic respiration to release more energy. Glucose + oxygen  Carbon dioxide + water + 2898kJ energy
  28. 28. What happens when you need more energy but there’s not enough oxygen?
  29. 29. Muscle cells (anaerobic respiration) • Prolonged physical activity - O2 supplied not enough - O2 needed > O2 supplied - muscle cells undergo anaerobic respiration • Muscles in state of O2 deficiency  O2 debt occurred • Oxygen debt : muscle cells produce ATP without oxygen
  30. 30. • Glucose molecules break down partially into Lactic Acid C6H12O6 2C3H6O3 + Energy (150kJ) lactic acid • Energy low because much of energy still trapped within molecules of lactic acid. • High concentration of lactic acid may cause muscular cramp and fatigue, tiredness
  31. 31. “Repaying” oxygen debt • After the activity the person need to breathe deeply and rapidly to inhale more O2 - O2 is used to oxidise accumulated lactic acid to form CO2 and H2O (occur mainly in liver) Lactic acid + O2 CO2 + H2O + energy Remaining lactic acid converted into glycogen and stored in muscle cells
  32. 32. Oxygen Debt Question: How do sprinters pay back their oxygen debt at the end of a race? Answer: Sprinters will continue to breathe more deeply and rapidly for a number of minutes at the end of their race. This will enable them to pay back the oxygen debt, and allow lactic acid levels to fall.
  33. 33. Oxygen debt The amount of oxygen needed to remove lactic acid from muscle cells is called oxygen debt The time taken to remove all the lactic acid is called the recovery period
  34. 34. • Oxygen debt is paid off when all of lactic acid is removed (increasing breathing rate after vigorous activity)
  35. 35. Energy needed for vigorous exercise Glucose + oxygen  Carbon dioxide + water + 2898 kJ Glucose + Oxygen  Lactic acid + 150 kJ Total amount of energy needed for vigorous muscular contractions Aerobic respiration Anaerobic respiration
  36. 36. Why aerobic respiration produced more energy than anaerobic respiration???
  37. 37. Why are virtually all organisms aerobes? More ATP released in aerobic rather than in anaerobic respiration
  38. 38. Aerobic and Anaerobic Respiration RESPIRATION Anaerobic Respiration Alcoholic Fermentation Lactic Acid Production Aerobic Respiration C6H12O6 + 6O2  6CO2 + 6H2O + energy glucose oxygen carbon water dioxide C6H12O6  2C2H5OH + 2CO2 + energy glucose ethanol carbon dioxide • Occurs in yeast cells. C6H12O6  2C3H6O3 + energy glucose lactic acid • Occurs in muscle cells. • Leads to fatigue.
  39. 39.  SIMILARITIES  Cellular respiration  Involve the breakdown of glucose  Produces energy  Are catalyzed by enzymes  Occurs in animal and plants
  40. 40. Differences between Aerobic Respiration & Anaerobic Respiration Aerobic Respiration Items Anaerobic Respiration Almost every living cells Work in Certain plant, yeast, bacteria and muscle Required Oxygen requirement Not required Complete oxidation Oxidation of glucose Incomplete oxidation CO2, Water and Energy Product Yeast CO2, Ethanol and Energy Muscle Lactic acid and Energy
  41. 41. Differences between Aerobic Respiration & Anaerobic Respiration Aerobic Respiration Items Anaerobic Respiration Large amount Energy released Small amount Mitochondria and Site Cytoplasm cytoplasm C6H12O6 + 6O2 Glucose ↓ 6CO2 + H20 + 2898 kJ Energy Chemical Equation In Yeast: C6H12O6 Glucose ↓ 2CO2 + 2C2H5OH + 210 kJ Ethanol Energy In Muscle cells: C6H12O6 Glucose ↓ 2C3H6O3 + 150kJ Lactic acid Energy 38 molecules Number of ATP molecules produced 2 molecules
  42. 42. • This apparatus can be used to investigate how small living organisms respire such as woodlice, maggots or germinating seeds. Living organisms Gauze Hydrogen carbonate indicator – This will change colour from red to yellow when the carbon dioxide level increases due to respiration.
  43. 43. The germinating seeds are respiring and therefore releasing heat. The boiled seeds have been killed and are therefore not respiring anymore. Cotton wool Thermometer Thermal flask
  44. 44. 7.2 Analysing the respiratory structure and breathing mechanism in human and animal
  45. 45.  LEARNING OUTCOMES:  State the respiratory structures in humans and some animals  Describe the characteristics of respiratory surfaces in humans and other organisms  Describe breathing mechanisms in human and other organisms  Compare and contrast the human respiratory system with other organisms
  46. 46. Gaseous exchange: is the exchange of oxygen and carbon dioxide between the environment and the organism takes place in all organisms by diffusion
  47. 47. A ‘respiratory surface’ is the: area where gaseous exchange actually takes place
  48. 48. Adaptations of respiratory structures (General characteristics) 1. Moist – easy for gases to dissolve before diffuse 2. Thin – allow rapid diffusion of gases 3. Large surface area – efficient gaseous exchange 4. Covered by a network of blood capillaries – efficient exchange and transport of respiratory gases
  49. 49. Organisms acquire their oxygen: direct from the atmosphere dissolved in water 1 2
  50. 50. oxygen Unicellular organisms carbon dioxide maximum distance is 0.1 mm The distance is so small that diffusion is rapid enough for the cell’s needs Amoeba
  51. 51. Protozoa – Unicellular Organism Oxygen nutrients Carbon dioxide Waste products The respiratory surface of an unicellular organism is through plasma membrane
  52. 52. Adaptations 1. Small Size  large surface area to volume (TSA/V) ratio  rate of diffusion increases 2. Wet surroundings  plasma membrane constantly moist  gases easily dissolve and diffuse across respiratory surface. 3. Thin plasma membrane  rapid diffusion of gases
  53. 53. Unicellular Organism No need for specialized respiratory structure
  54. 54. • Concentration of O2 is higher in surrounding water compared to the cell, so O2 diffuse into the cell through plasma membrane by simple diffusion EXAM TIPS!!! • Concentration of CO2 is higher in the cell compared to the surrounding water, so CO2 diffuse out of the cell through plasma membrane by simple diffusion
  55. 55. As animals increase in size: What happens to their surface area to volume ratio? Surface area (cm): Volume (cm3): Surface area/volume:
  56. 56. The larger the size of organism, the smaller the TSA/V ratio
  57. 57. As animals increase in size: What happens to the rate of oxygen consumption? INCREASES What must happen to meet the increased demand? Specialised respiratory surfaces must develop
  58. 58. Give TWO reasons for this statement: Some types of animals exchange gases without specialised respiratory structures. 1. the size & shape of the body  body is extremely small & elongated, as in microscopic nematode worms: short diffusion pathway  the body may be thin & flattened, producing a large surface area for diffusion (as in flatworms) Nematode worm Flatworm
  59. 59. 2. if energy demands are low:  the relatively slow rate of gas exchange by diffusion may suffice even for a larger, thicker body e.g. a jellyfish
  60. 60. CO2 diffuses O out 2 diffuses in Earthworm Section through worm’s skin 0.04mm the blood vessels absorb the O2 and carry it to the body diffusion takes place through the thin skin of the worm 16
  61. 61. RESPIRATORY STRUCTURE in INSECTS
  62. 62. Respiratory structure of Insects The tracheal system
  63. 63. Body wall spiracle tracheole Body cell Trachea (Reinforced with rings of chitin which prevent from collapsing) AIR The tracheal system of an insect consists of spiracle, trachea, air sac and tracheoles
  64. 64. The tracheal system of insects consists of tiny branching tubes that penetrate the body
  65. 65. Spiracles  are pairs of holes found on the:  2nd & 3rd thoracic segments  first 8 abdominal segments Air sacs Spiracle Tracheae  lead into air-filled sacs Spiracles: Air enters the tracheae through spiracles Spiracles have valves which allow air, to go in and out of the body Air sacs: in some larger insects contain air that speeds up movement of gases during vigorous body movement.
  66. 66. The tracheal system of insects provides direct exchange between the air and body cells Body cell Tracheole Air sac Trachea Air Body wall
  67. 67. What are ‘tracheae’?  branched tubes that lead from spiracles  reinforced with rings of chitin which prevent them from collapsing Why is it important to support the tracheae? If trachea collapses, surface area is greatly reduced
  68. 68. Tracheoles: Numerous  Tiny, end within cells  Contains fluid at tip  Thin - 1 cell thick Why do tracheoles lack a chitin lining? So that the respiratory surface is very thin making the diffusion of oxygen into the cells easy
  69. 69. ADAPTATIONS OF TRACHEOLES • Large number- provide large surface area for gases exchange • Tip of tracheoles have thin permeable wall – allow rapid diffusion of respiratory gases • Tips of tracheoles have fluid - allow respiratory gases to dissolve • Direct contact with tissues and organs, O2 directly diffuse into the cells, and CO2 directly diffuse out of the cells (no need blood to transport)
  70. 70. Air enters the spiracle then flows into the: Tracheae Tracheoles Cells
  71. 71. A closer look at a spiracle of a pupa
  72. 72. Valves & hairs at a spiracle: reduce water loss Valve open Valve closed
  73. 73. Ventilation (Breathing) movements  ventilation is the active movement of air or water over an animal's respiratory surface  one-way flow of air through the animal occurs Air enters in: through the thorax Air emerges from the abdomen Circulatory system not involved in transporting O2 and CO2
  74. 74. VENTILATION IN GRASSHOPPER
  75. 75. Breathing Mechanism Expiration:  Abdominal muscles contract & flatten the body  volume of the tracheal system decrease  air pressure inside trachea increased  air is forced out through spiracles Inspiration:  Abdominal muscles relax & body returns to original shape  Spiracles open  air pressure inside tracheae lowered, air drawn in.
  76. 76. Compare Ventilation in mammals: Expiration:  muscles contract Inspiration:  is achieved passively Expiration:  muscles relax  is achieved passively Inspiration:  muscles contract
  77. 77. In insects: the circulatory system is not involved in respiration blood is colourless (no respiratory pigment)
  78. 78. Question: [Pg. 139] 1) Insects use a tracheal system for gas exchange, as shown below. R a) On the diagram use a line labelled R to show the respiratory surface. (1)
  79. 79. b) State two advantages of using a tracheal system for gas exchange. (2) 1. Oxygen is transported directly to cells 2. Provides a large surface area for gaseous exchange
  80. 80. Question: [pg. 140] 3) Gas exchange in insects involves pores in the cuticle which open into a network of tubes. These tubes have fine branches extending into all the tissues of the body. a) Name the following: The pores in the cuticle. (1) Spiracles The network of tubes. (1) Tracheal system
  81. 81. b) In larger insects, such as locusts, the passage of air through the tubes is helped by pumping movements of the abdomen. A student carried out an experiment to investigate the effect of carbon dioxide on the rate of these pumping movements. She set up the apparatus as shown in the diagram below:
  82. 82. The locust was left in the boiling tube for five minutes. The number of abdominal pumping movements during one minute was counted. The student then breathed out once through the straw into the boiling tube and immediately counted the number of abdominal movements during one minute. She repeated this procedure varying the number of times she breathed out into the boiling tube. The results are shown in the table below.
  83. 83. Number of times student breathed into boiling tube Number of abdominal pumping movements in one minute 0 16 1 59 2 61 3 58 4 60 i) State why the student left the locust in the boiling tube for five minutes before she began the first count. (1) For insect to acclimatise & reach a steady rate of breathing.
  84. 84. Number of times student breathed into boiling tube Number of abdominal pumping movements in one minute 0 16 1 59 2 61 3 58 4 60 ii) Describe and comment on the effect of breathing out into the boiling tube on the rate of abdominal pumping in the locust. (4) A slight increase in CO2 concentration. Resulted in a high rise in breathing rate. Addition of more CO2 did not result in a further increase. Brain is sensitive to slight rise in CO2 .
  85. 85. c) (i) During this experiment, the humidity of the air in the boiling tube may vary. Suggest how this experiment could be modified to control the humidity. (2) Adding silica gel. + water = pink
  86. 86. (ii) Suggest two factors, other than a change in carbon dioxide concentration and humidity, which may have affected the rate of abdominal pumping. (2) An increase in temperature. Animal becomes stressed.
  87. 87. RESPIRATORY STRUCTURE & BREATHING MECHANISM OF AMPHIBIANS
  88. 88. The respiratory structure in an amphibian Skin Lung
  89. 89. Adaptation of the skin for gases exchange 1.The skin is thin and highly permeable - To allow rapid diffusion of respiratory gases into the blood capillaries 2. Beneath the skin is a network of blood capillaries - To transport respiratory gases to and from body cells 3. The skin is kept moist by the secretion of mucus by glands found on the outer surface of the body - Facilitate rapid and efficient exchange of gases between the skin and the environment
  90. 90. Beneath the skin is a network of blood capillaries – to receive O2 and transport it to body cells
  91. 91. Adaptation of the Lung for gases exchange 1.The surface area for gases exchange is increased by numerous inner partition - To increase the surface area for gases exchange 2. Covered with a rich network of blood capillary - To transport respiratory gases to and from body cells 3. The membrane of the lungs thin and moist - Facilitate the efficient diffusion of respiratory gases in and out rapidly
  92. 92. Floor of the mouth lower  During inspiration, the nostrils open, the mouth closes, the glottis closes and the floor of the mouth cavity is lowered.  This decrease the air pressure inside the mouth cavity. As the result, air is drawn thorough the nostrils into the mouth cavity.  The nostrils close and the floor of the mouth cavity is raised to force the air through the glottis into the lungs. The lungs expand and gaseous exchange takes place.  During expiration, the nostrils open. The muscles of the body wall contracts to force the air from the lungs to the mouth cavity and nostrils.
  93. 93. RESPIRATORY STRUCTURE & BREATHING MECHANISM OF FISH
  94. 94. Respiratory Structure of Fish The Gill
  95. 95. Gill Structure
  96. 96. Operculum is a:  movable gill cover that encloses and protects the gills
  97. 97. Operculum
  98. 98. Operculum controls:  movement of water in and out of the opercular cavity like a valve
  99. 99. Gill: gill arch + gill filaments Gill arch Gill filaments
  100. 100. Usually 4 gill arches on either side of the fish:  support the gills
  101. 101. Gill filaments are thin Gill filament Gill raker [for filter feeding] Upper limb Lower limb
  102. 102. Each gill is made up of 2 rows of: gill filaments (primary lamellae) arranged in the shape of a V About 70 pairs of gill filaments
  103. 103. The upper & lower flat surfaces of each gill filament has rows of: evenly spaced folds or gill plates (secondary lamellae)
  104. 104. The gill plates (secondary lamellae): increase the surface area of the respiratory surface have a rich supply of blood capillaries
  105. 105. What makes fish gills look red? A rich blood supply.
  106. 106. The gill plates (secondary lamellae): are the exchange surfaces Primary lamellae or filaments Plate-like secondary lamellae
  107. 107. The gill plates (secondary lamellae): are two-cell thick Water Blood flow flow Longitudinal section of secondary lamella Primary lamellae or filaments Plate-like secondary lamellae
  108. 108. Gills are useless out of the water. WHY? Gill filaments stick together and surface area is reduced
  109. 109. Two types of flow: Countercurrent flow:  blood in the gill plates flows in the opposite direction to the water (in bony fish) Parallel flow [concurrent]:  when the two fluids travel in the same direction (in cartilaginous fish)
  110. 110. Countercurrent Mechanism
  111. 111. Explain how a countercurrent flow increases the efficiency of gaseous exchange.
  112. 112. Countercurrent Flow is more efficient: equlibrium is reached blood always comes in contact with water having a high O2 concentration
  113. 113. The structural Adaptation of the gills: a. Thin filament membrane to allow rapid diffusion of respiratory gases into the blood capillaries b. Rich supply of blood capillaries for efficient exchange and transport of respiratory gases c. Surrounded by water – moist -which enable respiratory gases to be dissolved d. Large surface area of filaments and lamellae for efficient gases exchange
  114. 114. The Mechanism of Countercurrent Exchange a. The water flows over the gills in one direction b. The blood flows in the opposite direction through blood capillaries in the lamellae c. As deoxygenated blood enters the blood capillaries, it encounters water with a higher oxygen content d. As the concentration of O2 is higher in water than in the blood, O2 diffuses into the blood e. And because the concentration of CO2 in the blood is higher than in water, CO2 diffuses from the blood into the water
  115. 115. Breathing Mechanism in Fish EXPIRATION INSPIRATION
  116. 116. Inspiration Expiration
  117. 117. • Absorb dissolved oxygen from the surrounding water • The membrane of the gill filaments is thin – allows the absorption of respiratory gases INHALATION EXHALATION into the blood capillaries • The filaments are supplied with blood capillaries – for efficient exchange and transport of respiratory gases
  118. 118.  During Inhalation, the bony fish opens its mouth and lowers the floor of the mouth.  The pressure inside the mouth falls below that of the external pressure. This causes water to enter the mouth. At the same time, it causes the operculum to press against the body.  Gaseous exchange occurs as water flows past the grills. Water then passes out through the operculum . The operculum opens due to increased the pressure in the mouth.
  119. 119. RESPIRATORY STRUCTURE AND BREATHING MECHANISM OF HUMAN
  120. 120. RESPIRATORY STRUCTURE IN HUMAN LUNGS
  121. 121. The Human Respiratory System Nasal cavity Pharynx Larynx (‘voice box’) Trachea (‘windpipe’) Lungs Diaphragm - separates chest from abdomen
  122. 122. Components of the lower respiratory tract
  123. 123. Sequence air passes into human lungs: 2. Pharynx [throat] 1. nasal passages 4. trachea 3. larynx lung 5. bronchi 6. bronchioles 7. alveoli
  124. 124. What happens as air passes through the nasal passages? Cilia Cell membrane Mucus
  125. 125. Give TWO functions of mucus in the respiratory system.
  126. 126. The wall of the trachea is:  held open by horizontally C-shaped bands of cartilage  strengthened
  127. 127. Each lung is surrounded by a pleural cavity Pleural cavity: contains pleural fluid is air-tight Pleural fluid: lubricates space between two layers
  128. 128. Drainage from pleural cavity
  129. 129. Alveoli
  130. 130. alveolus
  131. 131. The Human Respiratory System The wall of each alveolus is only one cell thick. The inner surface is coated with a thin film of moisture. It is supplied by a capillary whose wall is also only one cell thick. This is the site where exchange of gases takes place!
  132. 132. Alveoli form the gas exchange surface
  133. 133. Alveolar wall – 1 cell thick consists of very thin, flattened cells: reducing the distance over which diffusion must occur Simple Squamous Simple Cuboidal Basement membrane Simple Columnar
  134. 134. Diameter of capillary is smaller than that of a RBC and so: RBC move relatively slowly  more time for gaseous exchange RBC are squeezed  bend into an umbrella shape – expose more of their SA to the alveolus:  more uptake of O2
  135. 135. Fig. 11 Gaseous exchange inside an alveolus.
  136. 136. 1. Gaseous exchange in humans take place in the lungs 2. Air enters lungs through : trachea  bronchi  bronchioles  alveoli 3. Trachea is supported by cartilage to prevent it from collapse during inhalation
  137. 137. Large number of alveoli in the lungs Walls are made of a single of cells Walls secrete a thin lining of moisture Surrounded by a network of blood capillaries Increased surface area for gases exchange Gases can diffuse rapidly across the thin walls Gases can dissolve in moisture and diffuse easily across walls Can transport oxygen and CO2 efficiently • l ADAPTATION IN ALVEOLUS
  138. 138. The mechanism of ventilation (breathing)
  139. 139. A Respiratory Cycle  Consists of • An inspiration (inhalation) • An expiration (exhalation)
  140. 140. Gas Pressure and Volume Relationships
  141. 141. A change in volume causes pressure to change
  142. 142. The volume of the thoracic cavity changes by:  movements of the:  diaphragm  intercostal muscles TWO types of intercostal muscles between each rib
  143. 143.  slant forwards & downwards  contract during inspiration  slant backwards & downwards  contract during expiration
  144. 144. Fig. 12 Position of intercostal muscles. The internal intercostal muscles contract for the ribcage to return back The external intercostal muscles contract to pull the ribcage up and out
  145. 145. Mammals ventilate their lungs by:  negative pressure breathing, which pulls air into the lungs Air inhaled Air exhaled Lung INHALATION Diaphragm contracts (moves down) EXHALATION Diaphragm relaxes (moves up) Diaphragm Rib cage expands as external intercostal muscles contract Rib cage gets smaller as external intercostal muscles relax Diaphragm is “dome-shaped Diaphragm flattens out.
  146. 146. Inspiration: an active process
  147. 147. Expiration: is largely a passive process
  148. 148. Inspiration Expiration Inspiration  The external intercostals muscles relax while internal intercostals muscles contract, this raising the ribs upwards and outward.  At the same time, the diaphragm muscles contract and flatten.  Both actions above increase the volume of the rib cage, causing its pressure to decreases.  Since atmospheric pressure is greater, air is drawn lungs the lungs and they inflate.
  149. 149. Mechanism of Breathing What happens to your intercostal muscles when you are breathing? When you inhale, you… Relax your Internal intercostal muscles and Contract your External intercostal muscles When you exhale, your… External intercostal muscles Relax and your Internal intercostal muscles Contract
  150. 150. Using a Bell Jar to demonstrate the action of Diaphragm
  151. 151. rubber sheet (diaphragm) What happens to the balloons when the rubber sheet is pulled downwards ? The balloons inflate when the rubber sheet is pulled downwards. Ans: glass tube (trachea) air space of bell jar (pleural cavity) side tube (bronchus) wall of bell jar balloon (lung) (thoracic wall) handle balloons are inflated as rubber sheet is pulled downwards air
  152. 152. rubber sheet (diaphragm) What happens when the rubber sheet is released ? The balloons return to their original shape when it is released. Ans: glass tube (trachea) air space of bell jar (pleural cavity) side tube (bronchus) wall of bell jar balloon (lung) (thoracic wall) handle balloons are inflated as rubber sheet is pulled downwards air
  153. 153. rubber sheet (diaphragm) When rubber sheet is pulled downwards, volume inside bell jar increases and pressure decreases. Air is sucked into the balloons and inflated them. . . Ans: glass tube (trachea) air space of bell jar (pleural cavity) side tube (bronchus) wall of bell jar balloon (lung) (thoracic wall) handle balloons are inflated as rubber sheet is pulled downwards air Explain how it works.
  154. 154. Explain how it works. rubber sheet (diaphragm) When rubber sheet is released, it becomes flattened. Volume inside bell jar decreases but pressure increases. Balloons return to original size and force air out. Ans: glass tube (trachea) air space of bell jar (pleural cavity) side tube (bronchus) wall of bell jar balloon (lung) (thoracic wall) handle balloons are inflated as rubber sheet is pulled downwards air
  155. 155. glass tube (trachea) air space of bell jar (pleural cavity) side tube (bronchus) air wall of bell jar balloon (lung) (thoracic wall) rubber sheet (diaphragm) handle balloons are inflated as rubber sheet is pulled downwards Explain why this model does not truly and fully reflect the actual conditions in man.
  156. 156. It is because : • The rubber sheet is controlled by hand – the movement of diaphragm is automatic ( contraction brought about by diaphragm muscles ) • The rubber sheet is flattened at rest – the diaphragm is dome-shaped
  157. 157. • The rubber sheet is pulled downwards to fill the balloons with air – the diaphragm is flattened during inspiration • The wall of the bell-jar is rigid – rib cage is movable and relatively elastic • The cavity is filled with air – the pleural cavity is filled with pleural fluid
  158. 158. Using a Rib Cage Model to demonstrate the action of Intercostal Muscles
  159. 159. Which parts of the human chest are represented by rod P, rod Q, rod R and the elastic band respectively ? Rod P, rod Q, rod R and the elastic band represent the backbone, sternum, ribs and intercostal muscles respectively. Ans: A rod R at position Y B elastic band rod Q at position X rod Q at position Y rod R at position x rod P
  160. 160. What movement of the human body is demonstrated when rods Q and R are raised from position X to position Y ? Upward movement of the chest is demonstrated when rods Q and R are raised from position X to position Y. Ans: A rod R at position Y B elastic band rod Q at position X rod Q at position Y rod R at position x rod P
  161. 161. How is the movement in Question 2 brought about in the human body ? It is brought about by the contraction of intercostal muscles. Ans: A rod R at position Y B elastic band rod Q at position X rod Q at position Y rod R at position x rod P
  162. 162. What process occurs in the human body as a result of the movement referred to in Question 2 ? Ans: Inspiration. A rod R at position Y B elastic band rod Q at position X rod Q at position Y rod R at position x rod P
  163. 163. Describe and explain the sequence of events involved in this process referred in Question 2. During inspiration the volume of the thorax is increased and the pressure is then reduced. Air is forced into the lungs. Ans: A rod R at position Y B elastic band rod Q at position X rod Q at position Y rod R at position x rod P
  164. 164. BREATHING MECHANISMS IN HUMAN INHALATION EXHALATION External intercostal muscles contract External intercostal muscles relax Internal intercostal muscles relax Internal intercostal muscles contract Rib cage move upwards and outwards Rib cage move downwards and inwards Diaphragm contracts and flattens Diaphragm relaxes and returns to dome-shaped Volume of thoracic cavity increase resulting in reduced air pressure in alveoli Volume of thoracic cavity decrease resulting in higher air pressure in alveoli Higher atmospheric pressure outside causes air to rush in Air is forced out of lungs
  165. 165. Structures Inhalation Exhalation External intercostal muscles Internal intercostal muscles Rib cage Diaphragm Volume Pressure Air flow
  166. 166. 1. Respiratory structures involve in gaseous exchange: a) Across plasma membrane b) Tracheal system - insects c) Gills - fish d) Skin e) Lungs
  167. 167. Common characteristics of respiratory structures • Moist (gaseous dissolving & diffusion) • Thin (rapid diffusion) • Large surface area per volume • Network of blood capillaries beneath the respiratory surfaces.
  168. 168. Compare and contrast the human respiratory system with that of other organisms
  169. 169. Adaptati on Organis ms Large surface area Respiratory structure Moisture Network of blood capillaries Protozoa Small size Plasma membrane Dissolved gases None Insects Numerous tracheoles Tracheoles Tip of tracheoles None Fish Numerous filaments and lamellae filaments and lamellae Dissolved gases Available Amphibians Lungs skin Lungs and skin Wet skin Available Humans Numerous alveoli Moist Available
  170. 170. Respirometer is used to find: the RATE of respiration measured as: volume of oxygen consumed/g/minute
  171. 171. Coloured fluid in manometer
  172. 172. What is the purpose of the glass beads in tube X? Control Suggest how a temperature of 25C could be obtained simultaneously in tube X and Y. Place in a water bath
  173. 173. Respirometer
  174. 174. Respirometer
  175. 175. END OF PART 1

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