School of Dentistry SUNYAB PGY452 Respiratory Lectures March 5 2015 Daniel D Swartz Ph D Lecture 2 Vascular Filtration and Reabsorption Lung Volumes and Ventilation Reading Assignment Berne Levy chapter 21 pages 430 443 SNS releases epinephrine NE to cause dilation Smooth muscle cells 2 Pulmonary Vascular Metabolic Regulation Mucus gland M atropine ANS PNS SNS PNS releases Ach to cause constriction ALVEOLAR CAPILLARY MEMBRANE surface tension ALVEOLAR AIR O 2 CO 2 surfactant alveolar Type II cell alveolar Type I cells 0 5 interstitial space endothelial cells Q pulmonary capillary inactivated serotonin norepinephrine bradykinin RBC captropril angiotensin I endothelial cells Nitric oxide NO angiotensin II ACE interstitial space Filtration Reabsorption in Systemic Capillaries Aortic blood pressure 120 80 mmHg mean 100 mmHg Pcap 32 mmHg 25 mmHg Ponc 25 mmHg 15 mmHg Filtration Reabsorption Q Ponc colloid osmotic pressure reabsorption Pcap capillary hydrostatic pressure filtration Filtration Reabsorption in Pulmonary Capillaries Pulmonary arterial blood pressure 25 8 mmHg mean 15 mmHg Ponc 25 25 mmHg mmHg Pcap 12 mmHg Right Ventricl e Q 8 mmHg Left atrium Reabsorption Causes of pulmonary edema Pcap Ponc Pulmonary Edema Left Heart Failure increase Pcap Lung volume increase Lung blood pressure increases Loss of plasma protein decreased Ponc Starvation Increase permeability fire hot air Bacterial toxins Toxic shock syndrome Lung Volumes and Pulmonary Function Test SYMBOLS Primary C Concentration of gas in blood F Fractional concentration in dry gas P Pressure or partial pressure Q Vo lume of blood Q Vo lume of blood per unit time R Respiratory exchange ratio S Saturation of hemoglob in with O2 V Vo lume of gas V Vo lume of gas per unit time Secondary Symbols for Gas Phase Secondary Symbols for Blood Phase A Alveolar a arterial B Barometric c capill ary D Dead Space c end capill ary E Expired i ideal I Inspired v venous L Lung mixed venous T Tidal Examples Concentration in arterial blood of O2 CaO2 Fractional concentration in expired air of N2 FEN2 Partial pressure in mixed venous blood of O2 P O2 Inspiratory and Expiratory Muscles Inspiration active process at all lung volumes except FRC Diaphragm External intercostals Expiration normally passive during respiration at rest Becomes active during 1 exercise 2 cough 3 vomiting 4 lung diseases that increase airway resistance asthma 5 speaking and singing Internal intercostals Abdominal muscles Spirometer for Measuring Lung Volumes Lung Volumes and Capacities TLC RV ERV VT IRV Primary determinants of lung volumes sex age and height 20 variability Uses 1 compare to normal values 2 Longitudinal studies Example Volume or Capacity Calculation VC 5 L IC 4 L FRC 2 L RV IC FRC VC RV 4 2 5 1 Fig 21 1 B L Lung Volume and Capacity Ratios RV to TLC ratio RV TLC normal is 25 Elevated ratio secondary to RV elevation obstructive pulmonary diseases Elevated ratio secondary to TLC decrease chronic bronchitis restrictive lung disease pulmonary fibrosis Factors Elastic recoil of lung Stretch of the lung compliance Muscle strength of inspiratory muscles Recoil of the chest wall When chest wall muscles are weak the FRC decreases lung elastic recoil chest wall muscle force In the presence of airway obstruction the FRC increases premature airway closure Measurement of RV and TLC body plethysmography Boyles Law P1 X V1 P2 V V helium dilution C1 X V1 C2 V1 V2 Helium Dilution Technique Fig 21 2 B L C1 10 Helium V1 6 Liters C2 6 Helium V2 4L Body Plethysmograph Technique Boyles Law P1 X V P2 V V FRC P1 P2 are mouth pressure before and after inspiratory effort V is the change in volume of the box Fig 21 3 B L Forced Expiratory Volumes FORCED EXPIRATORY VOLUMES FEV 1 3L FVC 4L 1 second FEV 1 Volume of air forcefully expired in 1 second FVC Forced Vital Capacity FEV 1 ratio 3L 4L 75 normal value FVC Factors that decrease FEV 1 FVC muscle strength airway resistance lung compliance FEV 1 FVC Forced Vital Capacity FEV 1 ratio 3L 4L 75 normal value FVC Forced Expiratory Volume and Emphysema Factors that decrease FEV 1 FVC muscle strength airway resistance lung compliance FEV 1 TLC TLC VC 1L 1 sec VC FRC RV FRC FEV 1 1L 3L 33 FVC RV NORMAL EMPHYSEMA EMPHYSEMA In obstructive diseases such as emphysema muscle strength is decreased lung compliance is increased and airway resistance is increased due to smooth muscle constriction and mucus plugging of the airways These changes lead to increases in RV FRC and TLC and decreases in VC and FEV 1 FVC FVC 3L of VC Expiration Peek Expiratory flow rate Forced expiratory volume Forced vital capacity Forced expiratory flow Expiration FV C Spirogram FEF 25 75 Forced expiratory flow from 25 75 VC also called MMEF Mid Maximal Expiratory Flow Increase R will decrease FEF Fig 21 12 B L Clinical Methods Inspiration Inspiratory muscles recoil of lung airway resistance Flow Volume Loop
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