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RESPIRATORY SYSTEM

RESPIRATORY SYSTEM. Arjun Maitra Asst.Professor Dept.of Physiology PCMS&RC. LECTURE SLIDES FROM THE CLASSES TAKEN DURING 2008-09 SESSION. Topic: Respiratory System Lecture taken for: B.ScNursing Useful for: MBBS, BPT. TO MY STUDENTS

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RESPIRATORY SYSTEM

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  1. RESPIRATORYSYSTEM Arjun Maitra Asst.Professor Dept.of Physiology PCMS&RC

  2. LECTURE SLIDES FROM THE CLASSES TAKEN DURING 2008-09 SESSION Topic: Respiratory System Lecture taken for: B.ScNursing Useful for: MBBS, BPT

  3. TO MY STUDENTS HERE I HAVE TRIED TO SIMPLIFY THE HUGE SUBJECTWITH ANIMATIONS, DIAGRAMS, FLOW CHARTS & RELEVENT MCQs. DIFFERENT TEXT BOOKS AND REFERENCE BOOKS HAVE BEEN USED FOR PREPARING THE CONTENTS. REMEMBERTHESE SLIDES ARE NOT THE SUBSTITUTE OF YOUR TEXT BOOKS ANIMATIONS AND DIAGRAMS ARE COLLECTED FROM DIFFERENT WEBSITE SOLELY FOR EDUCATION PURPOSE.

  4. PARTS OF RESPIRATORY SYSTEM • GAS EXCHANGING ORGAN • A PUMP TO VENTILATE THE LUNG *RESPIRARORY CENTERS *TRACTS & NERVES THAT CONNECT THE BRAIN TO THE RESPIRAROY MUSCLES

  5. Concept Of Partial Pressure P = nRT P = pressure n= number of moles R= gas constant T= absolute temperature V= volume V At Sea level Barometric Pressure = 760 mmHg

  6. Actual Values are different ………… why so? The PH2O at body temperature(37 degree C) = 47mmHg • Partial pressure of gases reaching lungs • PO2 = 149 mmHg • PCO2 = 0.3 mmHg • PN2 = 564 mmHg

  7. ON THE SUMMIT OF MT. EVEREST WHERE THE BAROMETRIC • PRESSURE IS ABOUT 250mmHg THE PARTIAL PRESSURE OF • OXYGEN IS • 0.1mmHg • 0.5mmHg • 5mmHg • 50mmHg • 100mmHg

  8. A JOURNEY INSIDE THE RESPIRATORY SYSTEM NASAL PASSAGE PHARYNX TRACHEA BRONCHI CONDUCTING ZONE(16 DIVISION) BRONCHIOLES (23 DIVISION) TERMINAL BRONCHIOLE RESPIRATORY BRONCHIOLES RESPIRATORY ZONE(7 DIVISION) ALVEOLAR DUCT ALVEOLUS

  9. SOME FACTS REGARDING MICRO ANATOMY OF LUNGS *NUMBER OF ALVEOLI 300 MILLION *ALVEOLAR CROSS SECTIONAL AREA 11,800 sqcm * TOTAL ARE FOR GASEOUS EXCHANGE IN BOTH LUNGS = 70sqm 0.5 mm

  10. BRONCHIAL INNERVATION ANS NON CHOLINERGIC SYMPATHETIC PARASYMPATHETIC NON ADRENERGIC CHOLINERGIC DISCHARGE ADRENERGIC DISCHARGE VIP MUSCARINIC RECEPTOR a1ADRENERGIC b2 ADRENERGIC BRONCHOCONSTRICTION SECRETION • BRONCHODIALATION • ACETYL CHOLINE RELEASE • BRONCHIAL SECRETION

  11. LUNGVOLUMES

  12. M / F VC = IRV+TV+ERV 4.8 / 3.1 IC = IRV+TV 3.8 / 2.4 FRC = ERV+RV 2.2 / 1.8 RESPIRATORY MINUTE VOLUME (R)= 6L/min ALVEOLAR VENTILATION (R)= 4.2L/min MAXIMUM VOLUNTARY VENTILATION = 125 – 170 L/min FEV1 = 80 – 83%

  13. Alveolar Ventilation • Alveolar ventilation rate (AVR) – measures the flow of fresh gases into and out of the alveoli during a particular time • Slow, deep breathing increases AVR and rapid, shallow breathing decreases AVR

  14. CALCULATE THE ALVEOLAR VENTILATION PER MINUTE • OF A PATIENT WITH RESPIRATORY RATE 14/min, TV 500ml • AND VITAL CAPACITY 7000ml • 4900 ml • 2000ml • 7700ml • 7000ml

  15. Breathe Easy 1. DIAPHRAGM DISPLACEMENT RANGE : 1.5 cm to 7 cm 2. INTERNAL INTERCOSTAL 3. EXTERNAL INTERCOSTAL 4. SCALENE 5. STERNOCLEIDO MASTOID 6. MUSCLES OF ANTERIOR ABDOMINAL WALL

  16. PRESSURE CHANGES DURING QUIET RESPIRATION Alveolar pressure ranges between +1mmHg to -1mmHg INTRA PLEURAL PRESSURE ( -2 to -6mmHg) Lowest at the end of inspiration

  17. COMPLIANCE OF THE LUNG & CHEST WALL • Relaxation Volume : It is the volume of lung that correspond to the volume of gas at lungs at the end of the quiet respiration where the pressure is 0 mmHg Relaxation Volume = Functional Residual Capacity

  18. Lung Compliance dV = LUNG COMPLIANCE dP Normal Value 0.2 L/cmH2O 1kPa= 7.5mmHg

  19. Decreased Compliance --------------- pulmonary congestion /interstitial pulmonary fibrosis Curve shifts to right and downward Increased Compliance ----------------emphysema Curve shifts to left and upward

  20. TOTAL LUNG CAPACITY DEPENDS UPON • SIZE OF THE AIRWAY • CLOSING VOLUME • LUNG COMPLIANCE • RESIDUAL VOLUME • WHICH OF THE FOLLOWING IS USED TO MEASURE THE RESISTANCE • TO SMALL AIRWAY • VITAL CAPACITY • FEV1 • MAX MID RESPIRATORY FLOW RATE • CLOSING VOLUME

  21. SURFACE TENSION & SURFACTANT WITHOUT SURFACTANT WITH SURFACTANT

  22. Approximate composition of Surfactant

  23. Proteins of Surfactant SP-A: Large glycoprotein . Function---- Regulation of the feedback uptake of surfactant SP-B & SP-C : small protein Function----- Facilitate the formation of mono molecular film of phospholipids SP-D : glycoprotein Function------ Involved in innate immunity

  24. POINTS TO REMEMBER • TYPE II PNEUMOCYTE DEVELOPS AT 24th WEEK OF GESTATION • SURFACTANT PRODUCTION BEGINS AT AROUND 34th WEEK OF GESTATION • Maturation of Surfactant : Glucocorticoids(Cortisol) • SURFACTANT INCREASES THE LUNG COMPLIANCE

  25. SCRATCH YOUR HEAD • PULMONARY SURFACTANT (PGI June 04) • CYTOKERATIN • MUCIN • SECRETED BY TYPE 1 PNEUMOCYTES • MAINTAIN ALVEOLAR INTEGRITY • UNDER ELECTRON MICROSCOPY EOSINOPHILIC • NODULES ARE FOUND • SURFACTANT PRODUCTION AT LUNGS STARTS AT (AI 01) • 28 WEEKS • 32 WEEKS • 34 WEEKS • 36 WEEKS

  26. FACTS ABOUT MECHANICS OF RESPIRATION WORK = FORCE X DISTANCE Work of Breathing g/cm2 X cm3 = g X cm TYPES OF WORK IN RESPIRATORY SYSTEM Non elastic work Viscous Resistance = 7% Airway Resistance = 28% Elastic work = 65% Total work = 0.3 – 0.8 kg/min Work of breathing increases in Emphysema, asthma, congestive heart failure with dyspnea, orthopnea

  27. VENTILATION PERFUSION RATIO UNEVEN VENTILATION IN DIFFERENT PART OF LUNG Ventilation is less at the Apex of the lung. Intra pleural pressure at the base of the lung -2.5 cm of H2O Intra pleural pressure at the apex of the lung -10cm of H2O UNEVEN BLOOD FLOW TO THE DIFFERENT REGION OF LUNG Blood flow is more at the base than the apex Gravity

  28. VENTILATION PERFUSION RATIO • Total lungs 0.8 • Base of the lung 0.5 • Apex of the lung 3.0

  29. Pulmonary pathologies

  30. GASEOUS EXCHANGE & TRANSPORT

  31. Gases move Downhill

  32. Gas content of Blood

  33. OXYGEN • 250 ml O2/min IS TRANSPORTED VIA BLOOD TO TISSUES • 99% BOUND TO HEMOGLOBIN • 1% IN SOLUTION • 4.6 ml OF O2 /dl OF BLOOD IS REMOVED BY TISSUES AT REST

  34. HEMOGLOBIN & OXYGEN BINDING WITH Hb INCREASES THE O2 CARRYING CAPACITY BY 70 FOLD OXYGEN BINDS REVERSIBLY WITH Hb Hb+O2 HbO2 THE REACTION IS OXYGENATION REACTION TIME IS 0.01s

  35. SOME NUMERICAL FACTS TO REMEMBER 1g of Fully Saturated Hb contains 1.39ml of O2 (in vitro) Traditional figure ---- 1g of Hb contains 1.34ml of O2 (in vivo) Arterial blood contains 19.8mlO2/dl Venous blood contains 15.2mlO2/ dl O2 in Solution 0.003ml/dl of blood/mmHg PO2

  36. OXYGEN DISSOCIATION CURVE • Characteristic Sigmoid shape is due to the T-R interconversion. sigmoidal curve reflects the four-stage loading of oxygen • oxygen loading (lungs) occurs over flat portion of curve • oxygen unloading (tissues) occurs over steep portion of curve Bohr Effect: The decrease in O2 affinity of hemoglobin when the pH of the blood falls.

  37. Hemoglobin is almost completely saturated at a PO2 of 70 mm Hg • Further increases in PO2 produce only small increases in oxygen binding • Only 20–25% of bound oxygen is unloaded during one systemic circulation • If oxygen levels in tissues drop: • More oxygen dissociates from hemoglobin and is used by cells

  38. FACTORS AFFECTING HEMOGLOBIN SATURATION

  39. THE NORMAL VALUE OF P50 ON THE O – D CURVE IN AN ADULT IS • 1.8 kPa • 2.7 kPa • 3.6 kPa • 4.5 kPa

  40. Gas content of Blood

  41. Transport of carbon dioxide • Dissolved in plasma: (7-10%) • Carbaminohemoglobin: (15-30%) • As bicarbonate: (60-70%) • CO2 + H2O H2CO3 H+ + HCO3- catalyzed carbonic anhydrase • H+ + Hb- HHb • chloride shift

  42. Dissolved CO2 CO2 Dissolved CO2 CO2 CO2 + H2O H2CO3 Carbamino Hb HCO3 HCO3 H+ Cl Cl HHb @ Hb HbO2 @ O2 O2 O2 O2 H2O H2O Tissue Red Blood Cell CO2 Transport CA Plasma

  43. HALDANE EFFECT BINDING OF OXYGEN REDUCES THE AFFINITY OF DEOXYGENATED HEMOGLODIN TOWARDS CO2

  44. v v 55 At Hb SO2=75% At Hb SO2=95% 50 CO2 Concentration (Vol%) a 45 50 55 40 45 PCO2 (mmHg) Haldane effect

  45. REGULATION OF RESPIRATION • VOLUNTARY SYSTEM CEREBRAL CORTEX • CORTICOSPINAL TRACT • RESPIRATORY MOTOR NEURONS • AUTOMATIC SYSTEM PONS &MEDULLA • EFFERENTS LOCATED IN WHITE MATTER OF SPINAL CORD • BETWEEN LATERAL &VENTRAL CORTICOSPINAL TRACT • CONVERGE ON PHRENIC MOTOR NEURONS (C3 – C5)

  46. AUTOMATIC SYSTEM PONS &MEDULLA • EFFERENTS LOCATED IN WHITE MATTER OF SPINAL CORD • BETWEEN LATERAL &VENTRAL CORTICOSPINAL TRACT • CONVERGE ON PHRENIC MOTOR NEURONS (C3 – C5) • EXTERNAL INTERCOSTAL MOTOR NEURONS (THORACIC CORD) • INERNAL INTERCOSTAL MOTOR NEURONS RECIPROCAL INNERVATION EXISTS

  47. MEDULLARY SYSTEMS I NEURONS DISCHARGE DURING INSPIRATION E NEURONS DISCHARGE DURING EXPIRATION RESPIRATORY CENTER DORSAL RESPIRATORY GROUP VENTRAL RESPIRATORY GROUP RESPIRATORY CONTROL PATTERN GENERATOR

  48. Dorsal respiratory group I neurons Ventral respiratory group e neurons+ I neurons • RESPIRATORY CONTROL PATTERN GENERATOR • PRE BOTZINGER COMPLEX OTHER CENTERS PNEUMOTAXIC CENTER FEEDBACK CONTROL TO THIS RECEPTORS FROM LUNG STRETCH RECEPTORS BY VAGUS

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