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The Respiratory System. ANATOMY OF THE RESPIRATORY SYSTEM.

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Presentation on theme: "The Respiratory System. ANATOMY OF THE RESPIRATORY SYSTEM."— Presentation transcript:

1 The Respiratory System

2 ANATOMY OF THE RESPIRATORY SYSTEM

3 The Respiratory Tract: The Lungs Alveoli TABLE OF CONTENT

4 1) Respiratory Tract : Nose through bronchi 2) The lungs. THE RESPIRATORY SYSTEM CONSISTS OF:

5 The respiratory tract further divided into the upper and lower respiratory tract

6 The upper respiratory tract from the nose through the pharynx

7 The lower respiratory tract (The Bronchial Tree) from the larynx to tertiary bronchi

8 The Bronchial Tree

9 Alveoli The Bronchial Tree Extends to Bronchioles and Alveoli

10 Bronchioles and Alveoli

11 Cartilage Plates No Cartilage but Smooth Muscles Bronchioles Cartilage Ring asthma attack

12 Cross Section Longitudinal Section Ciliary Lining of the Lower Respiratory Tract Cilia

13 Electron Micrograph of Cilia

14 The cilia beat upward and drive the debris-laden mucus to the pharynx, where it is swallowed.

15 THE LUNGS

16 The Lungs overlap with the respiratory tract. Secondary Bronchi Tertiary Bronchi Bronchioles Alveoli Bronchioles Alveoli Primary Bronchi Inside Lungs

17 THE LUNGS - consist of the left and the right lungs - The left lung is divided into two lobes; the right into three. - receives the bronchus, blood and lymphatic vessels, and nerves through its hilum. - The bronchi extend into alveoli

18 ALVEOLI

19 ~700 SF surface area

20 Alveoli consists of : 1) type I alveolar cells (95%), thin 2) type II alveolar cells (5%), secrete surfactant. 3) macrophages (dust cells), defense

21 -Each alveolus is surrounded with a basket of capillaries.

22 surrounded with capillaries

23 The respiratory membrane: 1) the wall of the alveolus 2) the endothelial wall of the capillary 3) their fused basement membranes

24 Alveoli contain elastic fibers which helps expiration.

25 Low blood pressure keeps alveoli dry.

26 Gas exchange occurs only in alveoli.

27 Dead Space - starts from nose to terminal bronchiole - where there is no gas exchange - ~ 150 ml terminal bronchiole

28 The Respiratory Tract: The Lungs Alveoli ANATOMY OF THE RESPIRATORY SYSTEM SUMMARY

29 ventilation gas exchange transport by blood gas exchange

30 MECHANICS OF VENTILATION

31 Driving Force for Air Flow Resistance to Airflow Measurements of Ventilation Alveolar Ventilation TABLE OF CONTENTS

32 Terms: inspiration or inhalation: breathing in expiration or exhalation: breathing out

33 Driving Force for Air Flow Airflow driven by the pressure difference between atmosphere (barometric pressure) and inside the lungs (intrapulmonary pressure). 760 mmHg

34 atmospheric pressure = 760 mmHg Before inspiration

35 atmospheric pressure = 760 mmHg

36 atmospheric pressure = 760 mmHg

37 atmospheric pressure = 760 mmHg

38 Mechanism for the Change in Intrapulmonary pressure Boyle’s Law: Volume x Pressure = Constant gas PV

39  Volume   Pressure  Volume   Pressure Inspiration:Expiration:

40  Volume   Pressure  Volume   Pressure Inspiration:Expiration: Can the lungs expand/shrink by themselves?

41 1) The Diaphragm 2) External Intercostal Muscles 3) Internal Intercostal Muscles 4) The Abdominal Muscles - the principal muscle of inspiration - pulls the diaphragm down, increasing all three dimensions of the thoracic cage. Major Respiratory Muscles 1) The Diaphragm 2) External Intercostal Muscles - Inspiration muscles - increases the anteroposterior and transverse dimensions of the chest. 1) The Diaphragm 2) External Intercostal Muscles 3) The Abdominal Muscles - Expiration muscles - pulls the diaphragm up, reducing the vertical dimension of the thoracic cage. 1) The Diaphragm 2) External Intercostal Muscles 3) The Abdominal Muscles 4) Internal Intercostal Muscles - Extra Expiration muscles

42 Coupling Between Lungs and Thoracic Cage

43 Visceral pleura covers the surface of each lung; parietal pleura lines the chest cavity. - The lungs and thoracic cage are coupled by the pleurae. pleural cavity - The two pleurae form the pleural cavity. - The pleural fluid serves to reduce friction during chest expansion. - Intrapleural pressure: The pressure in the pleural cavity is negative.

44 Parietal pleura visceral pleura Potential pleural cavity (negative intrapleural pressure) lung The thoracic cage is larger than the natural size of the lungs. Generation of the negative intrapleural pressure

45 Parietal pleura visceral pleura Potential pleural cavity (negative intrapleural pressure) air pneumathorax lung

46 Conclusion LungsThoracic Cage pleurae - pressure

47 Inspiration Contraction of 1) diaphragm 2) external intercostal muscles  The lungs are carried along.   Lung volume   pressure  Air flows in. active

48 passive Resting Expiration Relaxation of 1) diaphragm 2) external intercostal muscles  The lungs shrink.   Lung volume   pressure  Air flows out.

49 Forced Expiration Relaxation of 1) diaphragm 2) external intercostal muscles and Contraction of abdominal, internal intercostal and other accessory respiratory muscles.   Lung volume   pressure  Air flows out. active

50 Driving Force for Air Flow Atmosphere-lung pressure gradient Major respiratory muscles Coupling between lungs and thoracic cage SUMMARY

51 Resistance to Airflow

52 TABLE OF CONTENTS Resistance 1) Alveolar Surface Tension 2) Elastic Resistance 3)Airway Resistance Compliance

53 1)Alveolar Surface Tension - generated by a thin film of liquid over the surface of alveolar epithelium, - tends to cause a collapse of the alveoli, -Resists against inspiration.

54 Alveoli Alveolar surface tension is a resistance against inspiration.

55 -Surface tension is reduced by surfactant. ( type II alveolar epithelial cells) Pre-term infants don't have enough surfactant. type II surfactant

56 Resistance 1) Alveolar Surface Tension 2) Elastic Resistance 3)Airway Resistance - Against inspiration due to elastic fibers in the lungs and chest wall, - Increases in pulmonary fibrosis.

57 Resistance 1) Alveolar Surface Tension 2) Elastic Resistance 3)Airway Resistance - Due to friction, affected by airway caliber. - Against inspiration and expiration! - Increases during asthma attack (smooth muscle contraction in bronchiole.

58 Resistance 1) Alveolar Surface Tension 2) Elastic Resistance 3)Airway Resistance Compliance - The reciprocal of resistance, - An indicator of ease with which the lungs expand.

59 Measurements of Ventilation using Spirometer

60

61 Dead Space inspirationexpiration Alveolar ventilation rate = (tidal volume – dead space) x resp freq (/min)

62 Restrictive disorders - (pulmonary fibrosis) -  compliance &  vital capacity. Changes in Spirometric Measures

63 - No change in respiratory volumes -  FEV1. one-second forced expiratory volume Obstructive disorders Changes in Spirometric Measures

64 MECHANICS OF VENTILATION SUMMARY Driving Force for Air Flow Resistance to Airflow Measurements of Ventilation Alveolar Ventilation

65 NEURAL CONTROL OF VENTILATION

66 Rhythm?

67 1) inspiratory center - stimulates inspiration muscles. 2) expiratory center -inhibits the inspiratory center, -stimulates expiration muscles. Center in the medulla oblongata

68 The pons fine-tunes ventilation.

69 Afferent Connections to the Respiratory Centers the limbic system Hypothalamus Chemoreceptors the lungs

70 Chemoreceptor-initiated Reflexes Peripheral chemoreceptors - aortic and carotid bodies, - monitor O 2, CO 2 and pH of the blood. Central chemoreceptors - close to the surface of the medulla oblongata, - monitor the pH of the cerebrospinal fluid.

71  O 2,  CO 2, or  pH stimulate chemoreceptors reflex frequency and depth of respiration CHEMORECEPTOR-MEDIATED REFLEX

72 Voluntary Control - the motor cortex, - bypass the brainstem respiratory centers, - limited voluntary control.

73 GAS EXCHANGE in the LUNGS

74 ventilation gas exchange transport by blood gas exchange

75 - The gas exchange between alveolar air and the blood is via diffusion of O 2 and CO 2. - Diffusion of a gas is driven by O 2 and CO 2 partial pressure gradient. P O2 = 40 mmHg P CO2 = 46 mmHg P O2 = 104 mmHg P CO2 = 40 mmHg

76 The partial pressure of a gas refers to the share of the total pressure generated by a mixture of gases. O2O2 CO 2 N2N2 H2OH2O Total = 760 mmHg 5.3% 40 mmHg 13.6% 104 mmHg

77 P O2 = 40 mmHg P CO2 = 46 mmHg P O2 = 104 mmHg P CO2 = 40 mmHg Oxygen and carbon dioxide cross the respiratory membrane and the air-water interface easily.

78 Overview of Gas Exchange in the Lungs

79 Factors That Affect the Efficiency of Alveolar Gas Exchange 1. partial pressure 2.solubility 3.respiratory membrane thickness/area 4.ventilation-perfusion coupling

80 O2O2 CO 2 N2N2 O2O2 N2N2 H2OH2O Total = 760 mmHg Air a) High altitude b) Hyperbaric chamber c) Obstructive disease P O2 104 mmHg P CO2 40 mmHg 1) Partial pressure

81 CO2 has a higher solubility than O 2. CO 2 O 2 Pressure Gradient6 mmHg 64 mmHg P O2 104 mmHg P CO2 40 mmHg 2) Solubility P O2 40 mmHg P CO2 46 mmHg 1) Partial pressure

82 2) Solubility 1) Partial pressure 3) Respiratory membrane thickness/area

83 4) Ventilation-perfusion Coupling - average V-P ratio = autoregulated by: 2) Solubility 1) Partial pressure 3) Respiratory membrane thickness/area  P O2 and  P CO2 causes: 1)vasoconstriction of pulmonary arterioles 2)dilation of bronchioles

84 summary 1) Driving force for gas exchange 2) Factors that affect the efficiency of alveolar gas exchange

85 Gas transport by the blood

86 TABLE OF CONTENT 1) Carbon Dioxide Transport 2) Oxygen Transport

87 7% dissolved in the blood as a gas, 23% as carbamino- hemoglobin, 70% as carbonic acid in the plasma. Carbon Dioxide Transport

88 Oxygen Transport - About 98.5% of O2 in the blood are carried by hemoglobin. - The rest is physically dissolved in plasma.

89 Blood Oxygen Content -average 20 ml/dL -determined by: 1)saturation of hemoglobin 2) content of hemoglobin Hypoventilation CO poisoning anemia Hypoxemia

90

91 GAS EXCHANGE in the TISSUES 1. Carbon Dioxide Loading 2.Oxygen Unloading How to dissociate? O2O2

92 O2O2  P O2  dissociation  P CO2  dissociation  pH  dissociation DPG  dissociation (2,3-diphosphoglycerate)  Temperature  dissociation Dissociation of O2 from hemoglobin (HB) is affected by:

93 O2O2 High P O2, low P CO2  association with HG favor the loading of O 2 In Lungs 100% saturated

94 High P CO2, low P O2, low pH, DPG  dissociation of O 2 from HG favor the unloading O2O2 In tissues

95 High P CO2, low P O2, low pH, DPG  dissociation of O 2 from HG favor the unloading O2O2 In tissues

96 Utilization Coefficient - The amount of oxygen uptake by tissue versus the arterial blood oxygen content blood 20 ml O2/dL cell Utilization Coefficient = 4.4 ml / 20 ml = 22% 15.6 ml O2/dL 4.4 ml O2/dL

97 Function of Oxygen ?

98 with oxygen without oxygen glucose 2 ATP38 ATP

99 Can human beings produce oxygen?

100 Oxygen Toxicity - Excessive oxygen generates hydrogen peroxide and free radicals, which destroy enzymes and damage nervous tissue. - Oxidative toxicity with aging.

101 Hypercapnia -P CO2 < 37 mmHg - caused by hyperventilation Hypocapnia -P CO2 > 43 mmHg - caused by hypoventilation (respiratory diseases)

102 Summary of the Respiratory System

103 ventilation gas exchange transport by blood gas exchange

104 Oxyhemoglobin Dissociation Curve

105 Oxygen Dissociation & Temperature Active tissue - more O 2 released P O 2 (mmHg)

106 Oxygen Dissociation & pH Bohr effect: release of O 2 in response to low pH Active tissue - more O 2 released


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