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UNIT 2 RESPIRATION & PHONATION. Structure and Mechanics of Respiratory System. Pulmonary system Lungs and airways Upper respiratory system Lower respiratory system Chest wall system Necessary for normal vegetative and speech breathing. Pulmonary system: lower respiratory tract.
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UNIT 2 RESPIRATION & PHONATION SPPA 4030 Speech Science
Structure and Mechanics of Respiratory System • Pulmonary system • Lungs and airways • Upper respiratory system • Lower respiratory system • Chest wall system • Necessary for normal vegetative and speech breathing SPPA 4030 Speech Science
Pulmonary system: lower respiratory tract SPPA 4030 Speech Science
Pulmonary system: lower respiratory tract SPPA 4030 Speech Science
Chest wall system • Rib cage • Abdomen • Diaphragm SPPA 4030 Speech Science
Chest wall-Lung relation • Lungs not physically attached to the thoracic walls • Lungs: visceral pleura • Thoracic wall: parietal pleura • Filled with Pleural fluid • Ppleural < Patm - “pleural linkage” allows the lungs to move with the thoracic wall • Breaking pleural linkage Ppleural = Patm - pneumothorax SPPA 4030 Speech Science
Thorax SPPA 4030 Speech Science
Abdomen SPPA 4030 Speech Science
Diaphragm SPPA 4030 Speech Science
Respiratory muscles • Diaphragm • External intercostals • Internal intercostals (interosseus & intercartilaginous) • Costal elevators • Serratus posterior superior • Serratus posterior inferior • Sternocleidomastoid • Scalenes • Trapezius • Pectoralis major • Pectoralis minor • Serratus anterior • Transverse throacis • Rectus abdominis • External obliques • Internal obliques • Transversus abdominis • Quadratus lumborum SPPA 4030 Speech Science
Vt = Palv Palv < Patm (- Palv) P differential = density differential air molecules flowing into lungs = inspiration Vt = Palv Palv > Patmos(+ Palv) P differential = density differential air molecules flow out of lungs = expiration Moving Air Patm: atmospheric pressure Palv: alveolar pressure Vt: thoracic volume P = k/V: Boyle’s Law SPPA 4030 Speech Science
Changing lung volume ( Vlung) • pleural linkage:Vlung = Vthoracic • Vthoracic is • raising/lowering the ribs (circumference) • Raising: Vthoracic = inspiration • Lowering: Vthoracic =expiration • Raising/lowering the diaphragm (vertical dimension) • Raising: Vthoracic =expiration • Lowering: Vthoracic =inspiration SPPA 4030 Speech Science
Rest breathing vs. speech breathing • What are the goals? • Rest breathing • ventilation • Speech breathing • communication • ventilation SPPA 4030 Speech Science
Quantifying respiratory function • What measures would be useful? SPPA 4030 Speech Science
Measuring respiratory function Volume • Spirometer • “wet” and “dry” varieties SPPA 4030 Speech Science
Measuring respiratory function Pressure • Manometer • Specialized pressure transducers • measures pressure at specific locations • For example, • When swallowed, thoracic and abdominal pressures • “inserted” into the trachea for tracheal pressure • placed strategically along the vocal tract SPPA 4030 Speech Science
Measuring respiratory function Flow Rate • Spirometer • nonspeech • Pneumotachograph • Airflow during speech and nonspeech • Vented mask the covers mouth and nose SPPA 4030 Speech Science
Spirometry Lung Volume SPPA 4030 Speech Science
Lung Volumes REL SPPA 4030 Speech Science
A Review of volumes and capacities Tidal Volume (TV) • Volume of air inspired/expired during rest breathing. Expiratory Reserve Volume (ERV) • Volume of air that can be forcefully exhaled, “below” tidal volume. Inspiratory Reserve Volume (IRV) • Volume of air that can be inhaled, “above” tidal volume. Residual Volume (RV) • Volume of air left after maximal expiration. Measurable, but not easily so. Total Lung Capacity (TLC) • Volume of air enclosed in the respiratory system (i.e. TLC=RV+ERV+TV+IRV) Functional Residual Capacity (FRC) • Volume of air in the respiratory system at the REL (i.e. FRC=RV+ERV) Inspiratory capacity (IC) • TV + IRV Vital Capacity (VC) • Volume of air that can be inhaled/exhaled (i.e. VC=IRV +TV+ERV) SPPA 4030 Speech Science
NOTE • Some authors use the term FRC (functional residual capacity) instead of REL (resting end-expiratory level) • Behrman uses resting lung volume (RLV) • Refers to equivalent “place” in the lung volume space SPPA 4030 Speech Science
Typical Volumes & Capacities Vital Capacity (VC) 4-5 liters Total Lung Capacity (TLC) ~ one liter more than VC Resting Tidal Volume (TV) ~ 10 % VC Resting expiratory end level (REL) ~ 35-40% VC when upright Typical Rest Breathing Values Respiratory rate 12-15 breaths/minute Alveolar Pressure Palv +/- 2 cm H20 Airflow ~ 200 ml/sec Some typical adult values SPPA 4030 Speech Science
Respitrace SPPA 4030 Speech Science
Rest Breathing Volume 10 % VC at rest Alveolar Pressure Palv +/- 2 cm H20 Average Airflow 100-200 ml/sec Ratio of inhalation to exhalation ~40/60 to 50/50 Speech Breathing Volume 20-25 % VC @ normal loudness (note Kent reports lower values) 40 % loud speech Alveolar Pressure Palv + 8-10 cm H20 on expiration Average Airflow 100-200 ml/sec Ratio of inhalation to exhalation ~ 10/90 Speech vs. Life Breathing SPPA 4030 Speech Science
Respiratory System Mechanics SPPA 4030 Speech Science
Respiratory System Mechanics • It is spring-like (elastic) • Elastic systems have an equilibrium point (rest position) • What happens when you displace it from equilibrium? SPPA 4030 Speech Science
Displacement away from equilibrium Restoring force back to equilibrium Longer than equilibrium equilibrium SPPA 4030 Speech Science
Displacement away from equilibrium Restoring force back to equilibrium Shorter than equilibrium equilibrium SPPA 4030 Speech Science
Displacement away from equilibrium Restoring force back to equilibrium Shorter than equilibrium Longer than equilibrium equilibrium SPPA 4030 Speech Science
Equilibrium point ~ REL SPPA 4030 Speech Science
Displacement away from REL Restoring force back to REL Lung Volume Below REL Lung Volume Above REL REL SPPA 4030 Speech Science
Is the respiratory system heavily or lightly damped? SPPA 4030 Speech Science
Respiratory Mechanics: Bellow’s Analogy • Bellows volume = lung volume • Handles = respiratory muscles • Spring = elasticity of the respiratory system – recoil or relaxation pressure SPPA 4030 Speech Science
No pushing or pulling on the handles ~ no exp. or insp. muscle activity • Volume ~ REL • Patmos = Palv, no airflow SPPA 4030 Speech Science
At REL muscle force elastic force muscle force • pull handles outward from rest • V increases ~ Palv decreases • Inward air flow • INSPIRATION SPPA 4030 Speech Science
At REL muscle force elastic force muscle force • push handles inward from rest • V decreases ~ Palv increases • outward air flow • EXPIRATION SPPA 4030 Speech Science
Respiratory Mechanics: Bellow’s Analogy Forces acting on the bellows/lungs are due to • Elastic properties of the system • Passive • Always present • Muscle activity • Active • Under nervous system control (automatic or voluntary) SPPA 4030 Speech Science
Forces due to elasticity of system(no active muscle activity) • Recoil forces are proportionate to the amount of displacement from rest • Recoil forces ~ Palv • Relaxation pressure curve • Plots Palv due to recoil force against lung volume SPPA 4030 Speech Science
Relaxation Pressure Curve (as in Behrman) SPPA 4030 Speech Science
Relaxation Pressure Curve(Our version) SPPA 4030 Speech Science
60 40 relaxation pressure 20 REL Alveolar Pressure (cm H20) 0 -20 -40 -60 80 60 40 20 0 100 % Vital Capacity
Breathing for Life: Inspiration • pulling handles outward with net inspiratory muscle activity SPPA 4030 Speech Science
Breathing for Life: Expiration • No muscle activity • Recoil forces alone returns volume to REL SPPA 4030 Speech Science
60 40 20 relaxation pressure Alveolar Pressure (cm H20) 0 -20 -40 -60 80 60 40 20 0 100 % Vital Capacity Breathing for Life ~ 2 cm 10 %
Respiratory demands of speech • Conversational speech requires • “constant” tracheal pressure for driving vocal fold oscillation • brief, “pulsatile” changes in pressure to meet particular linguistic demands • emphatic and syllabic stress • phonetic requirements SPPA 4030 Speech Science
Conversational speech Volume solution Constant tracheal pressure 8-10 cm H20 Pulsatile solution Brief increases above/below constant tracheal pressure Driving analogy Volume solution Maintain a relatively constant speed Pulsatile solution Brief increases/decreases in speed due to moment to moment traffic conditions Respiratory demands of speech SPPA 4030 Speech Science
Example 10 5 Pressure wrt atmosphere 0 -5 Time SPPA 4030 Speech Science
Breathing for Speech: Inspiration • pulling handles outward with net inspiratory muscle activity • Rate of volume change is greater than rest breathing
Breathing for Speech 60 40 20 relaxation pressure ~ 8-10 cm Alveolar Pressure (cm H20) 0 -20 -40 20 % -60 80 60 40 20 0 100 % Vital Capacity