Respiratory system 2003

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  • 1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 20 Respiratory System Alveolar Duct
  • 2. Respiration
    • Movement of air into and out of the lungs (Ventilation or Breathing)
    • Exchange of O 2 and CO 2 between the lungs and the blood
    • Transport of these gases
    • Exchange of O 2 and CO 2 between the blood and the tissues
  • 3. Functions of the Respiratory System
    • Gas exchange
    • Regulation of blood pH
    • Voice production
    • Olfaction
    • Protection
  • 4. Anatomy of the Respiratory System
    • The respiratory system consist of the upper and lower respiratory tract
      • Upper respiratory tract: external nose, nasal cavity, pharynx, and associated structures
      • Lower respiratory tract: larynx, trachea, the bronchi, and lungs
  • 5. Fig. 20.1
  • 6.  
  • 7. Nose
    • Consist of the external nose and the nasal cavity
      • External nose
        • only visible structure
      • Nasal cavity
        • Nares or Nostrils – external openings
        • Choanae – openings to pharynx
        • Vestibule – anterior portion of nasal cavity
        • Hard palate – separates the nasal cavity from the oral cavity
        • Nasal septum – divides nose into right and left parts
        • Conchae – boney ridges in the nasal cavity
        • Meatus – Passageway beneath each conchae
  • 8. Nose
      • Provides an airway for respiration
      • Moistens and warms the entering air
      • Filters inspired air and cleans it of foreign matter
      • Serves as a resonating chamber for speech
      • Houses the olfactory receptors
  • 9. The Pharynx
    • Connects the nasal cavity and mouth to the larynx and esophagus inferiorly
    • Common passageway for air, food, and drink
    • Commonly called the throat
    • There are 3 regions:
      • Nasopharynx: air only
        • posterior to the choanae and superior to the soft palate
          • soft palate separates the nasopharynx from the oropharynx
      • Oropharynx: air and food
        • soft palate to the epiglottis
      • Laryngopharynx: primarily food and drink
        • epiglottis to the esophagus
  • 10. Fig. 20.2
  • 11. Larynx (Voice Box)
    • Anterior part of the throat, from the base of the tongue to the trachea
    • The three functions of the larynx are:
      • To provide an airway
      • To act as a switching mechanism to route air and food into the proper channels
        • Epiglottis: elastic cartilage that covers the laryngeal inlet during swallowing
        • Closure of the vestibular and vocal folds
      • To function in voice production
  • 12. Fig. 20.3
  • 13. Vocal Cords
    • Two pairs of ligaments
    • False vocal cords (vestibular folds)
      • Superior mucosal folds
      • Have no part in sound production
    • True vocal cords (vocal folds)
      • Inferior mucosal folds composed of elastic fibers
      • The medial opening between them is the glottis
      • They vibrate to produce sound as air rushes up from the lungs
      • Laryngitis: Inflammation of the vocal folds
  • 14. Fig. 20.4
  • 15. Sound Production
    • Sound: Vibration of the vocal folds as air moves past them
    • Loudness: depends on the amplitude of the vibration, which is determined by the force at which the air rushes across the vocal cords
    • Pitch: determined by the length and tension of the vocal cords, which changes the frequency of the vibrations
    • Sound is “shaped” into language by action of the tongue, lips, teeth, and other structures
    • The pharynx resonates, amplifies, and enhances sound quality
  • 16. Trachea
    • Descends from the larynx through the neck to the fifth thoracic vertebra
    • Composed of dense regular connective tissue and smooth muscle reinforced with 15-20 C-shaped rings of hyaline cartilage, which protect the trachea and keep the airway open
    • The mucous membrane lining the trachea is made up of goblet cells and pseudostratified ciliated columnar epithelium
      • Goblet cells produce mucus
    • It ends by dividing into the two primary bronchi
  • 17. Main Bronchi
    • The right and left bronchi are formed by the division of the trachea
    • Right primary bronchus is wider, shorter and more vertical than the left
      • Common site for an inhaled object to become lodged
    • By the time that incoming air reaches the bronchi, it is warmed, cleansed and saturated with water vapor
  • 18. Lungs
    • Principal organs of respiration
    • Base rest on diaphragm and the apex extends superiorly to ~2.5 cm above the clavicle
    • Right lung has 3 lobes, while the left has only 2 lobes
  • 19. The Tracheobronchial Tree
    • Once inside the lungs each main bronchus
      • Subdivides into lobar (secondary) bronchi
      • Then segmental (tertiary) bronchi
      • Finally giving rise to the bronchioles, which subdivide many times to give rise to the terminal bronchioles
    • ~16 generations of branching from the trachea to the terminal bronchioles
  • 20. The Tracheobronchial Tree
    • Terminal bronchioles divide into respiratory bronchioles, which have a few attached alveoli
      • Alveoli – small air filled chambers where gas exchange between the air and blood takes place
    • Respiratory bronchioles lead to alveolar ducts, then to terminal clusters of alveolar sacs composed of alveoli
    • Approximately 300 million alveoli
      • Account for most of the lungs’ volume
      • Provide tremendous surface area for gas exchange
    • ~7 generations of branching occur from the terminal bronchioles to the alveolar ducts
  • 21. Fig. 20.5
  • 22. Fig. 20.6
  • 23. Fig. 20.7
  • 24. The Tracheobronchial Tree
    • As air passageways become smaller, structural changes occur
      • Cartilage support structures decrease
      • Amount of smooth muscle increases
      • Epithelium types change
    • Terminal bronchioles are mostly smooth muscle with no cartilage, which allows the bronchioles to alter their diameter when a change in air flow is needed (i.e. during exercise)
  • 25. Alveoli
    • Alveolar walls:
      • Are a single layer of type I pneumocytes
        • Squamous epithelial cells
        • Compose 90% of the alveolar surface
        • Permit gas exchange by simple diffusion
      • Type II pneumocytes
        • Round or cube-shaped secretory cells that produce surfactant
        • Surfactant reduces surface tension, which makes it easier for the alveoli to expand
  • 26. Respiratory Membrane
    • Where gas exchange between air and blood occurs
    • It is very thin to facilitate the diffusion of gases
    • Consists of:
      • Thin layer of fluid lining the alveolus
      • Alveolar epithelium
      • Basement membrane of the alveolar epithelium
      • A thin interstitial space
      • Basement membrane of the capillary endothelium
      • The capillary endothelium
  • 27. Fig. 20.8
  • 28. Pleura
    • Thin, double-layered serous membranes
    • Parietal pleura
      • Covers the thoracic wall, diaphragm, and mediastinum
    • Visceral pleura
      • Covers the external lung surface
    • Pleural cavity
      • Negative pressure space between the parietal and visceral pleura
    • Pleural Fluid
      • Fills the pleural cavity
      • Made by the pleural membranes
      • Serves as a lubricant
      • Holds the pleural membranes together
  • 29. Fig. 20.9
  • 30.  
  • 31. Blood Supply to Lungs
    • Lungs are perfused by two circulations: pulmonary and bronchial
    • Pulmonary circulation
      • Pulmonary arteries: supply deoxygenated systemic blood to be oxygenated
        • Ultimately feed into the pulmonary capillary network surrounding the alveoli
      • Pulmonary veins: carry oxygenated blood from lungs back to the heart
    • Bronchial circulation
      • Bronchial arteries: provide systemic oxygenated blood to the lung tissue
        • Supply all lung tissue except the alveoli
      • Bronchial veins: carry the deoxygenated blood back to the heart
  • 32.
    • Inspiration: movement of air into the lungs
      • Muscles involved are the diaphragm and those that elevate the ribs and sternum
      • As the diaphragm and other muscles of inspiration contract and the rib cage rises and thoracic volume increases
    • Expiration: movement of air out of the lungs
      • Muscles actively involved are those that depress the ribs and sternum (usually only with forceful expiration)
      • Largely a passive process
      • M uscles of inspiration relax, the rib cage descends due to gravity and the thoracic cavity volume decreases
    • Pressure changes in the thoracic cavity change air pressure in the lungs, which in turn causes ventilation
      • largest change in thoracic volume is due to the diaphragm
    Ventilation
  • 33. Fig. 20.10
  • 34. Pressure Changes and Airflow
    • Physical Principles Influencing Pulmonary Ventilation
      • Air flows from areas of higher to lower pressure
        • If pressure is higher at one end of a tube (P 1 ) than at the other (P 2 ), air will flow down its pressure gradient
      • Changes in volume result in changes in pressure
        • As volume increases in a closed container the pressure decreases or as volume decreases pressure increases
        • This inverse relationship is known as Boyle’s law
      • Changes in tube diameter result in changes in resistance
        • Poiseuille’s law: resistance (R) to airflow is proportional to the diameter (d) of a tube raised to the fourth power (d 4 )
    F = F=Airflow (mm/min) P 1 – P 2 R
  • 35.  
  • 36. Alveoli Airflow Fig. 20.11
  • 37. Alveoli Airflow Fig. 20.11
  • 38. Fig. 20.11
  • 39.  
  • 40. Lung Recoil
    • Tendency for an expanded lung to decrease in size due to
      • Elastic fibers in the connective tissue
      • Surface tension
    • Two factors keep lungs from collapsing
      • Surfactant
      • Pleural Pressures
  • 41. Surfactant
    • Surf ace act ing a ge nt
    • Mixture of lipoprotein molecules
    • Acts in reducing surface tension in the alveoli
      • Attraction of water molecules to each other
    • Surfactant reduces the surface tension in alveoli by 10-fold
  • 42. Pleural Pressure
    • Pressure in the pleural cavity
      • When pleural pressure is less than alveolar pressure alveoli expand
    • Subatmospheric pleural pressure is caused by
      • Removal of fluid from the pleural cavity
      • Lung recoil
  • 43. Measurement of Lung Function
    • Measurements can be used to
      • Diagnose disease
      • Track progress of disease
      • Track recovery from disease
    • Measurements include
      • Lung compliance
      • Pulmonary volumes and capacities
      • Minute ventilation
      • Alveolar ventilation
  • 44. Lung Compliance
    • Measurement of the ease with which the lungs and thorax expand
    • Volume increases for each unit of pressure change in alveolar pressure
      • Liters (volume of air)/Centimeter of H 2 O (pressure)
        • In a normal person = 0.13 L/cm H 2 O
      • Higher than normal compliance = less resistance to lung and thorax expansion
        • Emphysema
      • Lower than normal compliance = more resistance to lung and thorax expansion
        • Pulmonary fibrosis, infant respiratory distress syndrome, pulmonary edema, asthma, bronchitis, and lung cancer
  • 45. Pulmonary Function Tests
    • Spirometry is the process of measuring volumes of air that move into and out of the respiratory system
    • Spirometer – a device used to measure these pulmonary volumes
    • The following factors can cause variations in Pulmonary Volumes and Capacities
        • Sex
        • Age
        • Body Size
        • Physical Condition
  • 46. Pulmonary Volumes
    • Tidal volume (TV)
      • volume of air inspired or expired with each breath (approximately 500 ml at rest)
    • Inspiratory reserve volume (IRV)
      • amount of air that can be inspired forcefully after inspiration of the tidal volume (approximately 3000 ml at rest)
    • Expiratory reserve volume (ERV)
      • amount of air that can be forcefully expired after expiration of the tidal volume (approximately 1100 ml at rest)
    • Residual volume (RV)
      • volume of air still remaining in the respiratory passages and lungs after the most forceful expiration (approximately 1200 ml)
  • 47. Pulmonary Capacities
    • Sum of two or more pulmonary volumes
    • Inspiratory capacity (IC = IRV + TV)
      • Amount of air that a person can inspire maximally after a normal expiration (approximately 3500mL at rest )
    • Functional residual capacity (FRC = ERV + RV)
      • Amount of air remaining in the lungs after a normal expiration (approximately 2300mL at rest )
    • Vital capacity (VC = IRV + TV + ERV)
      • Maximum volume of air that a person can expel from the respiratory tract after a maximum inspiration (approximately 4600mL at rest )
    • Total lung capacity (TLC = IRV + ERV + TV + RV)
      • Sum of all lung volumes (approximately 5800 ml at rest)
  • 48. Fig. 20.12
  • 49. Pulmonary Function Tests
    • Forced expiratory vital capacity
      • individual inspires maximally and then exhales maximally as rapidly as possible
      • volume of air expired at the end of the test is the person’s forced expiratory vital capacity
    • Forced expiratory volume in 1 second (FEV 1 )
      • amount of air expired during the first second of the test
      • decreased FEV 1 can be caused by airway obstruction, asthma, emphysema, tumors, pulmonary fibrosis, silicosis, kyphosis, and scoliosis
  • 50. Minute Ventilation
    • Minute Ventilation
      • equals tidal volume (~500mls) times respiratory rate (~12 breaths/min.)
      • Average ~ 6 L/min
      • Only measures movement of air into and out of the lungs, not amount of air available for gas exchange
    • Dead space
      • Areas of the respiratory system where gas exchange does not take place
      • Includes the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles (~150 mLs)
      • Nonfunctional alveoli can also contribute, but are rare in healthy individuals
  • 51. Alveolar Ventilation
    • Alveolar ventilation (V A )
      • volume of air available for gas exchange
    • Slow, deep breathing increases AVR and rapid, shallow breathing decreases AVR
    V A = ƒ X
      • (V T – V D )
    (mLs/min) (frequency, breaths/min)
      • (Tidal Volume – Dead Space)
      • (mLs/respiration)
  • 52.  
  • 53. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 54. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 55. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 56. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 57. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 58. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 59. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA).
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + ).
    • In the chloride shift, as HCO 3 - diffuse out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them.
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 60. Gas Exchange in the Tissues
    • In the tissues, CO 2 diffuses into the plasma and into RBC. Some of the CO 2 remains in the plasma
    • In RBC, CO 2 reacts with H 2 O to form carbonic acid (H 2 CO 3 ) in a reaction catalyzed by the enzyme carbonic anhydrase (CA)
    • H 2 CO 3 dissociates to form bicarbonate ions (HCO 3 - ) and hydrogen ions (H + )
    • In the chloride shift, as HCO 3 - diffuses out of the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) into them
    • Oxygen (O 2 ) is released from hemoglobin (Hb). O 2 diffuses out of RBCs and plasma into the tissues
    • H + combine with Hb, which promotes the release of O 2 from Hb (Bohr effect)
    • CO 2 combines with Hb. Hb that has released O 2 readily combines with CO 2 (Haldane effect)
  • 61. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 62. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 63. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 64. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 65. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 66. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 67. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 68. Gas Exchange in the Lungs
    • In the lungs, CO 2 diffuses from the RBCs and plasma into the alveoli
    • Carbonic anhydrase (CA) catalyzes the formation of CO 2 and H 2 O from carbonic acid (H 2 CO 3 )
    • Bicarbonate ions (HCO 3 - ) and H + combine to replace H 2 CO 3
    • In the chloride shift, as HCO 3 - diffuse into the RBC, electrical neutrality is maintained by the diffusion of chloride ions (Cl - ) out of them
    • Oxygen diffuses into the plasma and into RBCs. Some of the O 2 remains in the plasma. O 2 binds to Hb
    • H + are released from Hb, which promotes the uptake of O 2 by Hb (Bohr effect)
    • CO 2 is released from Hb. Hb that is bound to O 2 readily releases CO 2 (Haldane effect)
  • 69.  
  • 70.