CMDS 5050 Glen Nowell Lecture 7 Respiratory System (PDF)

CHAPTER 7 THE RESPIRATORY SYSTEM LECTURE SPEECH SCIENCE OCTOBER 18, 2024 Slides composed by M. Kiefte School of Communication Sciences & Disorders Dalhousie University Presented by Glen Nowell, SLP-Reg  LAND ACKNOWLEDGEMENT Dalhousie University is in Mi’kma’ki...

CHAPTER 7 THE RESPIRATORY SYSTEM LECTURE SPEECH SCIENCE OCTOBER 18, 2024 Slides composed by M. Kiefte School of Communication Sciences & Disorders Dalhousie University Presented by Glen Nowell, SLP-Reg  LAND ACKNOWLEDGEMENT Dalhousie University is in Mi’kma’ki, the ancestral and unceded territory of the Mi’kmaq. We are all treaty people.  RESPIRATION The primary purpose of respiration is ventilation. Physical: gas exchange. Chemical: food + O2 → H2O + CO2 + heat. Mechanical: inhalation & exhalation. PHASES OF SPEECH PRODUCTION respiration power supply lungs, lower respiratory tract phonation vibrating elements vocal folds acoustic source resonance system of filters pharyngeal, oral, & nasal cavities acoustic filter changes shape with lips, tongue, and palate  KINETIC THEORY OF GASES molecules constantly moving exert force when they hit walls of container change in volume → change in # molecules/volume. VOLUME AND PRESSURE Boyle’s Law If gas kept at constant temperature, pressure & volume are inversely proportional. p ∝ 1/V  PHYSICS OF BREATHING Air flows from higher pressure to lower pressure. Volume of air flow is proportional to difference. greater pressure difference → faster airflow  PHYSICS OF BREATHING Inspiration (inhalation): increase thoracic (chest) volume → negative pressure Expiration (exhalation): decrease thoracic (chest) volume → positive pressure RESPIRATORY PASSAGE Vocal tract filters, moistens, warms air 1 nasal cavity (nose) 2 oral cavity (mouth) 3 pharynx (throat) RESPIRATORY PASSAGE 4 larynx (voicebox) protects lower respiratory passages thoracic fixation hold breath & stiffen thoratic cavity & lock in volume upper & lower respiratory tracts separated by vocal folds RESPIRATORY PASSAGE Vocal tract filters, moistens, warms air 5 trachea (rough artery) windpipe 6 bronchi extend from trachea  RESPIRATORY PASSAGE nasal cavity (1) pharynx (11,12,14) larynx (7,8,13,15–17) trachea (18)  BRONCHIAL TREE trachea horseshoe shaped cartilage anterior to esophagus incomplete portion located posteriorly shared wall with esophagus last tracheal cartilage bifurcates forming 2 mainstem bronchi lined with mucous membrane (epithelium) and cilia left lung has three, due to heart  BRONCHIAL TREE cartilage that forms the ribs if this was solid, you would have no necjk flexibility 2 mainstem bronchi extend from trachea to lungs similar to trachea repeatedly subdivide (secondary bronchi, tertiary bronchi, etc. 20–28 times) until microscopic BRONCHIOLES AND ALVEOLI bronchioles final division of bronchi. cross-sectional area of subdivisions greater than parent → terminal bronchioles → alveolar ducts → alveoli BRONCHIOLES AND ALVEOLI alveoli small depressions in terminal bronchioles & air sacs. Facilitates rapid exchange of O2 & CO2.  PROPERTIES OF ALVEOLI lung elasticity is collapsing force Respiratory Distress Syndrome (RDS): some elasticity due to tissue resistance lack of surfactant in the lungs most elasticity (≈2/3) due to surface tension balanced by surfactant Surfactant lowers the surface tension/interfacial tension between blood and air in alveoli  LUNGS bronchi, bronchioles, alveoli, & blood vessels thorax (chest) between diaphragm & neck mostly heart & lungs thoracic cavity space bounded by sternum, rib cage, spine, & diaphragm diaphragm dome-shaped muscle separating lung bases from abdominal viscera abdomen digestive system, glands, other organs FRAMEWORK OF BREATHING MECHANISM: TORSO 1 vertebral (spinal) column 2 rib cage 3 pelvis  VERTEBRAE #s not relevant for exam Cervical: (7) Thoracic: (12) Have articular facets for ribs. Abdominal: (15) Lumbar: (5) Sacral: (5) Fused together. Coccygeal: (3–5) or Coccyx  RIBS Ribs: 12 pairs of flat, arch-shaped bones. slope downward from back to front attached to sternum via costal cartilage lowest ribs share cartilage MOVEMENT OF RIBS IN BREATHING Thoracic cavity increases in 3 dimensions: 1 Vertical: contraction of diaphragm. 2 Transverse: raising of curved ribs. 3 Anteroposterior: simultaneous forward & upward movement of sternum. Muscles that lower ribs are expiratory. Muscles that raise ribs are inspiratory.  ROTATIONAL AXES OF RIBS Bucket handle: transverse increase. Pump handle: anteroposterior increase.  PELVIC GIRDLE “floor” for abdominal viscera.  PECTORAL GIRDLE Provides attachment for the upper limbs of torso. Clavicle: collarbone. Scapula: shoulder blade. Articulates with lateral end of clavicle.  PECTORAL GIRDLE Provides attachment for the upper limbs of torso. Clavicle: collarbone. Scapula: shoulder blade. Articulates with lateral end of clavicle.  PLURAE “shrink wrap” costal: rib parietal (costal) pleura membrane lining thoracic cavity visceral pleura membrane surrounding lungs intrapleural fluid between pleurae intrapleural pressure or transpulmonary pressure always less than atmospheric intrapleural gases absorbed by visceral pleura other gases cannot enter  PLEURAE pleural linkage: lung surfaces held to inner surface of thoracic wall. provide friction-free lung/thoracic surfaces expansion of thoracic wall, elastic recoil of lungs pleurisy or pleuritis inflammation of the pleural membranes. pneumothorax accumulation of gas within pleural cavity resulting in collapsed lung.  RESPIRATORY PRESSURES air pressure reference pressure zero by definition intrapleural pressure between visceral and parietal pleurae always negative relative to alveolar pressure within lungs Intra-oral pressure and subglottal pressure changes from positive to negative with inspiration subglottal pressure below larynx is always same as alveolar pressure -: inhaling stop breathing: 0  MUSCULATURE OF BREATHING MECHANISM 1 muscles contract Boyle’s Law: The pressure of a given mass of a gas is inversely proportional to its volume at 2 thoracic cavity increases volume a constant temperature. 3 lungs expand—pleural linkage 4 negative pressure—Boyle’s Law 5 air flows into lungs 6 muscles cease contracting. 7 thoracic cavity shrinks—elastic recoil 8 positive pressure—Boyle’s Law 9 air exhaled  PRESSURE AND FLOW alveolar pressure zero at beginning & end of inspiration flow is zero when pressure is zero alveolar pressure drops during inspiration drop in alveolar pressure results in inward flow of air no pressure of air at start/ end both ex & insp PRESSURE AND FLOW alveolar pressure zero at beginning & end of expiration flow is zero when pressure is zero alveolar pressure increases during expiration increase in alveolar pressure results in outward flow of air  PRESSURE AND FLOW alveolar pressure zero at beginning & end of expiration flow is zero when pressure is zero alveolar pressure increases during expiration increase in alveolar pressure results in outward flow of air  MUSCULATURE OF BREATHING MECHANISM In quiet breathing, expiratory forces are passive. forced expiration: exhalation beyond passive expiration. facilitated by contraction of abdominal muscles. DIAPHRAGM divides torso into thorax & abdomen inverted bowl shape may be only muscle involved in quiet breathing. central tendon: tough sheet of inelastic tissue contraction of diaphragm results in flattening thorax enlarges vertically  ACTION OF DIAPHRAGM 1. Thoracic volume increases. 2 Intrapulmonic pressure decreases. 3 Abdominal volume decreases. 4 Intra-abdominal pressure increases. INTERCOSTAL MUSCLES Between ribs. Internal intercostals: depress ribs (A) External intercostals: elevates ribs (B). 90 degrees from each other INTERCOSTAL MUSCLES  ACCESSORY MUSCLES OF RESPIRATION muscles that lower ribs → exhalation muscles that raise ribs → inhalation used when panicking *** THORACIC MUSCLES transversus thoracic deep muscle, sternum → fans out to costal cart. Depress ribs Interesting, but not on exam  THORACIC MUSCLES costal elevators (levator costarum) vertebrae (C7– T11) → next lower Rib raisers. serratus posterior vert → ribs. superior elevate ribs inferior downward force on ribs Interesting, but not on exam  THORACIC MUSCLES pectoralis major upper costal cartilage, sternum, clavicle → humerus pulls sternum & ribs up when humerus fixed pectoralis minor upper ribs near cartilage → scapula deep to pectoralis major elevates ribs when scapula fixed subclavius clavicle → first rib elevates first rib when clavical fixed  THORACIC MUSCLES serratus anterior upper ribs → scapula elevation of upper ribs when scapula fixed Interesting, but not on the exam MUSCLES OF THE NECK sternocleidomastoid sternum & clavicle → mastoid process of temporal bone. When head held fixed, bilateral contraction elevates sternum & clavical increasing antero-posterior size.  MUSCLES OF THE NECK part of panic breathing scalenes (anterior, medius, & posterior) deep muscles of anterolateral region of neck. Cervical vertibrae → 2 upper ribs (elevators). Interesting, not on the exam ANTEROLATERAL ABDOMINAL MUSCLES  ANTEROLATERAL ABDOMINAL MUSCLES Compress abdominal contents resulting in forced expiration. External obliques: lower ribs → abdominal aponeurosis. Largest, strongest, most superficial. Internal obliques: deep muscles that course opposite to external obliques. Same role as external obliques.  ANTEROLATERAL ABDOMINAL MUSCLES Transversus abdominis: horizontal course. Ribs, vertebrae, pelvic girdle → abdominal aponeurosis. Deepest. Rectus abdominis: superficial muscle parallel to midline. Enclosed by abdominal aponeurosis. Pelvic girdle → lower ribs & xyphoid process.  POSTERIOR MUSCLES accessory muscles for respiration Serratus posterior superior: cervical & thoracic vertebrae → ribs elevates ribs Serratus posterior inferior: thoracic & lumbar vertebrae → lower ribs lowers ribs Interesting, not on the exam  POSTERIOR MUSCLES costal elevators (levatores costarum) vertibrae (C7–T11) → next lower rib Rib raisers subcostals inside back wall of rib cage lower ribs Interesting, not on the exam  ACTIVE INHALATION Action Effect Muscle contraction: increases thoracic dimensions diaphragm Vertical Intercostals Transverse Anteroposterior inward airflow to equalize pressure lungs expand with thoracic enlargement increased intraabdominal pressure abdominal viscera compressed by diaphragm restoring forces begin inspiratory muscles cease contraction  PASSIVE EXHALATION Action Effect upward force increases against vertical dimension of thorax decreases diaphragm Torque: rotational restoration force ribs unwind lungs want big, ribs want small potential energy → kinetic energy gravity acts on system restores thorax to rest position lung elasticity exerts restoring force on thoracic wall outward flow of air lung elasticity provides expiratory force  TORQUE product of tangential (twisting) force & distance from centre τ = Ftr cartilage is elastic—ribs obey Hooke’s Law restoring force is proportional to amount twisted  RATES OF BREATHING alveoli and alveolar ducts are still growing in first years of life lung and thoracic cavity size increases  PRESSURE RELATIONSHIPS IN CHEST CAVITY Alveolar pressure = 0 at beginning & end of inhalation & exhalation. Alveolar pressure > 0 during expiration & < 0 during inspiration. Intrapleural pressure falls during inspiration & rises during expiration.  PRESSURE RELATIONSHIPS IN CHEST CAVITY Alveolar pressure = 0 at beginning & end of inhalation & exhalation. Alveolar pressure > 0 during expiration & < 0 during inspiration. Intrapleural pressure falls during inspiration & rises during expiration MEASUREMENT OF PULMONARY SUBDIVISIONS spirometer device used to measure respiratory airflow and volumes  resting end-ex: a sigh reserve: amount we could’ve breathed but didn’t residua;: always present just can’t be accessed **** MEASUREMENT OF PULMONARY SUBDIVISIONS Spirogram: graphic recording of pulmonary subdivisions.  RESTING EXPIRATORY LEVEL Resting Expiratory Level (REL): equilibrium in respiratory system—roughly 40% of total lung volume end-point of quiet exhalation or End-Expiratory Level (EEL)  MEASUREMENT OF PULMONARY SUBDIVISIONS Lung volumes: non-overlapping volumes Lung capacities: combination of 2 or more lung volumes. Volumes and capacities are defined relative to REL.  LUNG VOLUMES Tidal Volume (TV) volume inhaled/exhaled in single respiratory cycle much greater for men than women—up to 2/3 more increases with increased physical work Inspiratory Reserve Volume (IRV) maximum volume that can be inhaled beyond that inhaled in TV cycle Expiratory Reserve Volume (ERV) maximum amount that can be exhaled following quiet exhalation Residual Volume (RV) quantity remaining in lungs after maximum exhalation  DEAD AIR last air to be inhaled and remains in upper respiratory system and bronchial tree no O2/CO2 exchange just in the alveoli  LUNG CAPACITIES Vital Capacity (VC) quantity that can be exhaled after maximum inhalation = IRV + TV + ERV Inspiratory Capacity (IC) maximum that can be inhaled from REL = TV + IRV Functional Residual Capacity (FRC) quantity of air at REL = ERV + RV Total Lung Capacity (TLC) quantity of air in lungs at maximum inhalation = TV + IRV + ERV + RV Lung volumes and capacities are often expressed as percentages of VC. SPIROGRAM  RESPIRATORY MEASUREMENTS VITAL CAPACITY RESPIRATORY MEASUREMENTS TOTAL LUNG CAPACITY  EFFECTS OF BODY POSITION Abdominal viscera press diaphragm upward. Increase in pulmonary blood volume decreases pulmonary air space.  BREATHING FOR SPEECH speech interrupted by ventilatory requirements egressive speech produced on outflowing air ingressive speech produced in inflowing air breath group number of syllables produced on one expiration  DIFFERENCES BETWEEN QUIET AND SPEECH BREATHING 1) oral cavity used for speech 2) respiratory cycles are different 40% inspiration in quiet 10% inspiration in speech 3) greater volume of air in speech quiet breathing ≈.5 L or 10% of VC about 500 ml per breath at 12–18 times/min or about 6–9 L/min 25–40% for speech depending on loudness 4) several additional muscles are required in speech diaphragm and external intercostals for quiet inspiration 5) quiet breathing is passive/reflexive Children show differences between speech and quiet breathing by two years old.  RESPIRATORY PRESSURES Subglottal pressure during sustained vowel is relatively constant Relaxation pressure too great for sustained vowel at high lung volumes due to recoil forces gravity muscle relaxation lung elasticity torque ribs are twisted, breathing exerts pressure which someone sustaining vowels creates a twisting force & reactive force twists it back  RELAXATION PRESSURE Relaxation pressure: pressure generated by entirely passive forces. = 0 at REL. positive following inhalation stays positive until returned to REL negative following forced expiration  RELAXATION PRESSURE CURVE pressure generated by entirely passive forces lungs, chest wall, abdominal viscera lower limit attributed to chest wall upper limit attributed to chest wall & lungs muscles change to maintain pressure louder —> sooner you’ll have to use expirtory muscles MAINTENANCE OF CONSTANT SUBGLOTTAL PRESSURE Checking action (breaking): muscular activity which prevents thorax-lung recoil from generating excessive subglottal pressure. Subglottal pressure is proportional to vocal intensity SEQUENCE OF MUSCLE ACTIVITY  WHAT FORCES ARE INVOLVED IN BREATHING? When lungs and ribcage are compressed, they want to recoil and get bigger. When lungs and ribcage are expanded, they want to recoil and get smaller. Colton and Casper, 1996, Page 298.  PULMONARY FUNCTION TESTING (PFT) Common spirometric measures: FVC Amount of air that can be exhaled forcefully after maximum inhalation FEV1 Amount of air that can be exhaled forcefully in one breath in one second norms based on age gender height size race SEVERITY OF REDUCTIONS IN FVC AND FEV1  FLOW-VOLUME LOOP (FVL) inhale as deeply as possible exhale as much as possible  PLETHYSMOGRAPH measures lung volumes air-tight box like a telephone booth commonly called a “body box” patients sit inside and volumes are measured based on Boyle’s Law all air is from external environment measures pressure on box from lung expansion