The Respiratory System

The Respiratory System
Major function-respiration Supply body with O2 for cellular respiration; dispose of CO2, a waste product of cellular respiration Its four processes involve both respiratory and circulatory systems Also functions in olfaction and speech © 2013 Pearson Education, Inc.

Processes of Respiration
Pulmonary ventilation (breathing)- movement of air into and out of lungs External respiration-O2 and CO2 exchange between lungs and blood Transport-O2 and CO2 in blood Internal respiration-O2 and CO2 exchange between systemic blood vessels and tissues Respiratory system Circulatory system © 2013 Pearson Education, Inc.

Respiratory System: Functional Anatomy
Major organs Nose, nasal cavity, and paranasal sinuses Pharynx Larynx Trachea Bronchi and their branches Lungs and alveoli © 2013 Pearson Education, Inc.

Nasal cavity Oral cavity Nostril Pharynx Larynx Trachea Carina of
Figure The major respiratory organs in relation to surrounding structures. Nasal cavity Oral cavity Nostril Pharynx Larynx Trachea Carina of trachea Left main (primary) bronchus Right main (primary) bronchus Left lung Right lung Diaphragm © 2013 Pearson Education, Inc.

Respiratory zone-site of gas exchange
Functional Anatomy Respiratory zone-site of gas exchange Microscopic structures-respiratory bronchioles, alveolar ducts, and alveoli Conducting zone-conduits to gas exchange sites Includes all other respiratory structures; cleanses, warms, humidifies air Diaphragm and other respiratory muscles promote ventilation PLAY Animation: Rotating face © 2013 Pearson Education, Inc.

The Nose Functions Provides an airway for respiration
Moistens and warms entering air Filters and cleans inspired air Serves as resonating chamber for speech Houses olfactory receptors © 2013 Pearson Education, Inc.

Two regions-external nose and nasal cavity
The Nose Two regions-external nose and nasal cavity External nose-root, bridge, dorsum nasi, and apex Philtrum-shallow vertical groove inferior to apex Nostrils (nares)-bounded laterally by alae © 2013 Pearson Education, Inc.

Figure 22.2a The external nose.
Epicranius, frontal belly Root and bridge of nose Dorsum nasi Ala of nose Apex of nose Naris (nostril) Surface anatomy © 2013 Pearson Education, Inc.

Figure 22.2b The external nose.
Frontal bone Nasal bone Septal cartilage Maxillary bone (frontal process) Lateral process of septal cartilage Minor alar cartilages Dense fibrous connective tissue Major alar cartilages External skeletal framework © 2013 Pearson Education, Inc.

Nasal cavity-within and posterior to external nose
The Nose Nasal cavity-within and posterior to external nose Divided by midline nasal septum Posterior nasal apertures (choanae) open into nasal pharynx Roof-ethmoid and sphenoid bones Floor–hard (bone) and soft palates (muscle) © 2013 Pearson Education, Inc.

Nasal vestibule-nasal cavity superior to nostrils
Vibrissae (hairs) filter coarse particles from inspired air Rest of nasal cavity lined with mucous membranes Olfactory mucosa Respiratory mucosa © 2013 Pearson Education, Inc.

Olfactory mucosa contains olfactory epithelium Respiratory mucosa
Nasal Cavity Olfactory mucosa contains olfactory epithelium Respiratory mucosa Pseudostratified ciliated columnar epithelium Mucous and serous secretions contain lysozyme and defensins Cilia move contaminated mucus posteriorly to throat Inspired air warmed by plexuses of capillaries and veins Sensory nerve endings trigger sneezing © 2013 Pearson Education, Inc.

Figure 22.3b The upper respiratory tract.
Cribriform plate of ethmoid bone Frontal sinus Sphenoid sinus Nasal cavity Posterior nasal aperture Nasal conchae (superior, middle and inferior) Nasopharynx Pharyngeal tonsil Nasal meatuses (superior, middle, and inferior) Opening of pharyngotympanic tube Nasal vestibule Uvula Nostril Oropharynx Hard palate Palatine tonsil Soft palate Isthmus of the fauces Tongue Lingual tonsil Laryngopharynx Hyoid bone Larynx Epiglottis Vestibular fold Thyroid cartilage Esophagus Vocal fold Cricoid cartilage Trachea Thyroid gland Illustration © 2013 Pearson Education, Inc.

Figure 22.3a The upper respiratory tract.
Olfactory nerves Olfactory epithelium Superior nasal concha and superior nasal meatus Mucosa of pharynx Middle nasal concha and middle nasal meatus Tubal tonsil Inferior nasal concha and inferior nasal meatus Pharyngotympanic (auditory) tube Hard palate Nasopharynx Soft palate Uvula Photograph © 2013 Pearson Education, Inc.

Nasal conchae-superior, middle, and inferior
Nasal Cavity Nasal conchae-superior, middle, and inferior Protrude medially from lateral walls Increase mucosal area Enhance air turbulence Nasal meatus Groove inferior to each concha © 2013 Pearson Education, Inc.

Functions of the Nasal Mucosa and Conchae
During inhalation, conchae and nasal mucosa Filter, heat, and moisten air During exhalation these structures Reclaim heat and moisture © 2013 Pearson Education, Inc.

In frontal, sphenoid, ethmoid, and maxillary bones
Paranasal Sinuses In frontal, sphenoid, ethmoid, and maxillary bones Lighten skull; secrete mucus; help to warm and moisten air © 2013 Pearson Education, Inc.

Homeostatic Imbalance
Rhinitis Inflammation of nasal mucosa Nasal mucosa continuous with mucosa of respiratory tract  spreads from nose  throat  chest Spreads to tear ducts and paranasal sinuses causing Blocked sinus passageways  air absorbed  vacuum  sinus headache © 2013 Pearson Education, Inc.

Muscular tube from base of skull to C6
Pharynx Muscular tube from base of skull to C6 Connects nasal cavity and mouth to larynx and esophagus Composed of skeletal muscle Three regions Nasopharynx Oropharynx Laryngopharynx © 2013 Pearson Education, Inc.

Figure 22.3c The upper respiratory tract.
Pharynx Nasopharynx Oropharynx Laryngopharynx Regions of the pharynx © 2013 Pearson Education, Inc.

Air passageway posterior to nasal cavity
Nasopharynx Air passageway posterior to nasal cavity Lining - pseudostratified columnar epithelium Soft palate and uvula close nasopharynx during swallowing Pharyngeal tonsil (adenoids) on posterior wall Auditory tubes drain and equalize pressure in middle ear; open into lateral walls © 2013 Pearson Education, Inc.

Passageway for food and air from level of soft palate to epiglottis
Oropharynx Passageway for food and air from level of soft palate to epiglottis Lining of stratified squamous epithelium Isthmus of fauces-opening to oral cavity Palatine tonsils-in lateral walls of fauces Lingual tonsil-on posterior surface of tongue © 2013 Pearson Education, Inc.

Passageway for food and air Posterior to upright epiglottis
Laryngopharynx Passageway for food and air Posterior to upright epiglottis Extends to larynx, where continuous with esophagus Lined with stratified squamous epithelium © 2013 Pearson Education, Inc.

Figure 22.3b The upper respiratory tract.
Cribriform plate of ethmoid bone Frontal sinus Sphenoid sinus Nasal cavity Posterior nasal aperture Nasal conchae (superior, middle and inferior) Nasopharynx Pharyngeal tonsil Nasal meatuses (superior, middle, and inferior) Opening of pharyngotympanic tube Nasal vestibule Uvula Nostril Oropharynx Hard palate Palatine tonsil Soft palate Isthmus of the fauces Tongue Lingual tonsil Laryngopharynx Hyoid bone Larynx Epiglottis Vestibular fold Thyroid cartilage Esophagus Vocal fold Cricoid cartilage Trachea Thyroid gland Illustration © 2013 Pearson Education, Inc.

Larynx Attaches to hyoid bone; opens into laryngopharynx; continuous with trachea Functions Provides patent airway Routes air and food into proper channels Voice production Houses vocal folds © 2013 Pearson Education, Inc.

Nine cartilages of larynx
All hyaline cartilage except epiglottis Thyroid cartilage with laryngeal prominence (Adam's apple) Ring-shaped cricoid cartilage Paired arytenoid, cuneiform, and corniculate cartilages Epiglottis-elastic cartilage; covers laryngeal inlet during swallowing; covered in taste bud-containing mucosa © 2013 Pearson Education, Inc.

Cricothyroid ligament Cricoid cartilage
Figure 22.4a The larynx. Epiglottis Thyrohyoid membrane Body of hyoid bone Thyroid cartilage Laryngeal prominence (Adam’s apple) Cricothyroid ligament Cricoid cartilage Cricotracheal ligament Tracheal cartilages Anterior superficial view © 2013 Pearson Education, Inc.

Corniculate cartilage
Figure 22.4b The larynx. Epiglottis Body of hyoid bone Thyrohyoid membrane Thyrohyoid membrane Cuneiform cartilage Fatty pad Vestibular fold (false vocal cord) Corniculate cartilage Arytenoid cartilage Thyroid cartilage Arytenoid muscles Vocal fold (true vocal cord) Cricoid cartilage Cricothyroid ligament Cricotracheal ligament Tracheal cartilages Sagittal view; anterior surface to the right © 2013 Pearson Education, Inc.

Photograph of cartilaginous framework of the larynx, posterior view
Figure 22.4c The larynx. Epiglottis Hyoid bone Thyroid cartilage Lateral thyrohyoid membrane Corniculate cartilage Arytenoid cartilage Glottis Cricoid cartilage Tracheal cartilages Photograph of cartilaginous framework of the larynx, posterior view © 2013 Pearson Education, Inc.

Photograph of posterior aspect
Figure 22.4d The larynx. Epiglottis Laryngeal inlet Corniculate cartilage Posterior cricoarytenoid muscle on cricoid cartilage Trachea (d) Photograph of posterior aspect © 2013 Pearson Education, Inc.

Vocal ligaments-deep to laryngeal mucosa
Larynx Vocal ligaments-deep to laryngeal mucosa Attach arytenoid cartilages to thyroid cartilage Contain elastic fibers Form core of vocal folds (true vocal cords) Glottis-opening between vocal folds Folds vibrate to produce sound as air rushes up from lungs © 2013 Pearson Education, Inc.

Vestibular folds (false vocal cords)
Larynx Vestibular folds (false vocal cords) Superior to vocal folds No part in sound production Help to close glottis during swallowing © 2013 Pearson Education, Inc.

Figure 22.5 Movements of the vocal folds.
Base of tongue Epiglottis Vestibular fold (false vocal cord) Vocal fold (true vocal cord) Glottis Inner lining of trachea Cuneiform cartilage Corniculate cartilage Vocal folds in closed position; closed glottis Vocal folds in open position; open glottis © 2013 Pearson Education, Inc.

Superior portion–stratified squamous epithelium
Epithelium of Larynx Superior portion–stratified squamous epithelium Inferior to vocal folds–pseudostratified ciliated columnar epithelium © 2013 Pearson Education, Inc.

Voice Production Speech-intermittent release of expired air while opening and closing glottis Pitch determined by length and tension of vocal cords Loudness depends upon force of air Chambers of pharynx, oral, nasal, and sinus cavities amplify and enhance sound quality Sound is "shaped" into language by muscles of pharynx, tongue, soft palate, and lips © 2013 Pearson Education, Inc.

Vocal folds may act as sphincter to prevent air passage
Larynx Vocal folds may act as sphincter to prevent air passage Example-Valsalva's maneuver Glottis closes to prevent exhalation Abdominal muscles contract Intra-abdominal pressure rises Helps to empty rectum or stabilizes trunk during heavy lifting © 2013 Pearson Education, Inc.

Windpipe–from larynx into mediastinum Wall composed of three layers
Trachea Windpipe–from larynx into mediastinum Wall composed of three layers Mucosa-ciliated pseudostratified epithelium with goblet cells Submucosa-connective tissue with seromucous glands Adventitia-outermost layer made of connective tissue; encases C-shaped rings of hyaline cartilage © 2013 Pearson Education, Inc.

Trachea Trachealis muscle Carina
Connects posterior parts of cartilage rings Contracts during coughing to expel mucus Carina Spar of cartilage on last, expanded tracheal cartilage Point where trachea branches into two main bronchi © 2013 Pearson Education, Inc.

Figure 22.6a Tissue composition of the tracheal wall.
Posterior Mucosa Esophagus Submucosa Trachealis muscle Lumen of trachea Seromucous gland in submucosa Hyaline cartilage Adventitia Anterior Cross section of the trachea and esophagus © 2013 Pearson Education, Inc.

Figure 22.6b Tissue composition of the tracheal wall.
Goblet cell Mucosa Pseudostratified ciliated columnar epithelium Lamina propria (connective tissue) Submucosa Seromucous gland In submucosa Hyaline cartilage Photomicrograph of the tracheal wall (320x) © 2013 Pearson Education, Inc.

Figure 22.6c Tissue composition of the tracheal wall.
Scanning electron micrograph of cilia in the trachea (2500x) © 2013 Pearson Education, Inc.

Bronchi and Subdivisions
Air passages undergo 23 orders of branching  bronchial (respiratory) tree From tips of bronchial tree  conducting zone structures  respiratory zone structures © 2013 Pearson Education, Inc.

Conducting Zone Structures
Trachea  right and left main (primary) bronchi Each main bronchus enters hilum of one lung Right main bronchus wider, shorter, more vertical than left Each main bronchus branches into lobar (secondary) bronchi (three on right, two on left) Each lobar bronchus supplies one lobe © 2013 Pearson Education, Inc.

Each lobar bronchus branches into segmental (tertiary) bronchi Segmental bronchi divide repeatedly Branches become smaller and smaller  Bronchioles-less than 1 mm in diameter Terminal bronchioles-smallest-less than 0.5 mm diameter © 2013 Pearson Education, Inc.

Figure 22.7 Conducting zone passages.
Trachea Superior lobe of left lung Left main (primary) bronchus Superior lobe of right lung Lobar (secondary) bronchus Segmental (tertiary) bronchus Middle lobe of right lung Inferior lobe of right lung Inferior lobe of left lung © 2013 Pearson Education, Inc.

From bronchi through bronchioles, structural changes occur Cartilage rings become irregular plates; in bronchioles elastic fibers replace cartilage Epithelium changes from pseudostratified columnar to cuboidal; cilia and goblet cells become sparse Relative amount of smooth muscle increases Allows constriction © 2013 Pearson Education, Inc.

Respiratory Zone Begins as terminal bronchioles  respiratory bronchioles  alveolar ducts  alveolar sacs Alveolar sacs contain clusters of alveoli ~300 million alveoli make up most of lung volume Sites of gas exchange © 2013 Pearson Education, Inc.

Figure 22.8a Respiratory zone structures.
Alveoli Alveolar duct Respiratory bronchioles Alveolar duct Terminal bronchiole Alveolar sac © 2013 Pearson Education, Inc.

Figure 22.8b Respiratory zone structures.
bronchiole Alveolar duct Alveolar pores Alveoli Alveolar sac © 2013 Pearson Education, Inc.

Alveolar and capillary walls and their fused basement membranes
Respiratory Membrane Alveolar and capillary walls and their fused basement membranes ~0.5- m-thick; gas exchange across membrane by simple diffusion Alveolar walls Single layer of squamous epithelium (type I alveolar cells) Scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins © 2013 Pearson Education, Inc.

Figure 22.9a Alveoli and the respiratory membrane.
Terminal bronchiole Respiratory bronchiole Smooth muscle Elastic fibers Alveolus Capillaries Diagrammatic view of capillary-alveoli relationships © 2013 Pearson Education, Inc.

Figure 22.9b Alveoli and the respiratory membrane.
Scanning electron micrograph of pulmonary capillary casts (70x) © 2013 Pearson Education, Inc.

Surrounded by fine elastic fibers and pulmonary capillaries
Alveoli Surrounded by fine elastic fibers and pulmonary capillaries Alveolar pores connect adjacent alveoli Equalize air pressure throughout lung Alveolar macrophages keep alveolar surfaces sterile 2 million dead macrophages/hour carried by cilia  throat  swallowed © 2013 Pearson Education, Inc.

Figure 22.9c Alveoli and the respiratory membrane.
Red blood cell Nucleus of type I alveolar cell Alveolar pores Capillary Capillary Macrophage Alveolus Endothelial cell nucleus Alveolus Alveolar epithelium Respiratory membrane Fused basement membranes of alveolar epithelium and capillary endothelium Alveoli (gas-filled air spaces) Red blood cell in capillary Type II alveolar cell Type I alveolar cell Capillary endothelium Detailed anatomy of the respiratory membrane © 2013 Pearson Education, Inc.

Occupy all thoracic cavity except mediastinum
Lungs Occupy all thoracic cavity except mediastinum Root-site of vascular and bronchial attachment to mediastinum Costal surface-anterior, lateral, and posterior surfaces Composed primarily of alveoli Balance–stroma-elastic connective tissue  elasticity © 2013 Pearson Education, Inc.

Heart (in mediastinum) Anterior mediastinum Sternum Anterior
Figure 22.10c Anatomical relationships of organs in the thoracic cavity. Esophagus (in mediastinum) Posterior Vertebra Root of lung at hilum • Left main bronchus Right lung • Left pulmonary artery Parietal pleura • Left pulmonary vein Visceral pleura Left lung Pleural cavity Thoracic wall Pulmonary trunk Pericardial membranes Heart (in mediastinum) Anterior mediastinum Sternum Anterior Transverse section through the thorax, viewed from above. Lungs, pleural membranes, and major organs in the mediastinum are shown. © 2013 Pearson Education, Inc.

Apex-superior tip; deep to clavicle
Lungs Apex-superior tip; deep to clavicle Base-inferior surface; rests on diaphragm Hilum-on mediastinal surface; site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves Left lung smaller than right Cardiac notch-concavity for heart Separated into superior and inferior lobes by oblique fissure © 2013 Pearson Education, Inc.

Lungs Right lung Superior, middle, inferior lobes separated by oblique and horizontal fissures Bronchopulmonary segments (10 right, 8–10 left) separated by connective tissue septa If diseased can be individually removed Lobules-smallest subdivisions visible to naked eye; served by bronchioles and their branches © 2013 Pearson Education, Inc.

Anterior view. The lungs flank mediastinal structures laterally.
Figure 22.10a Anatomical relationships of organs in the thoracic cavity. Intercostal muscle Rib Parietal pleura Lung Pleural cavity Visceral pleura Trachea Thymus Apex of lung Left superior lobe Right superior lobe Oblique fissure Horizontal fissure Right middle lobe Left inferior lobe Oblique fissure Right inferior lobe Heart (in mediastinum) Diaphragm Cardiac notch Base of lung Anterior view. The lungs flank mediastinal structures laterally. © 2013 Pearson Education, Inc.

Photograph of medial view of the left lung.
Figure 22.10b Anatomical relationships of organs in the thoracic cavity. Apex of lung Pulmonary artery Left main bronchus Left superior lobe Oblique fissure Pulmonary vein Left inferior lobe Cardiac impression Hilum of lung Oblique fissure Aortic impression Lobules Photograph of medial view of the left lung. © 2013 Pearson Education, Inc.

Figure 22.11 A cast of the bronchial tree.
Right lung Left lung Right superior lobe (3 segments) Left superior lobe (4 segments) Right middle lobe (2 segments) Right inferior lobe (5 segments) Left inferior lobe (5 segments) © 2013 Pearson Education, Inc.

Pulmonary circulation (low pressure, high volume)
Blood Supply Pulmonary circulation (low pressure, high volume) Pulmonary arteries deliver systemic venous blood to lungs for oxygenation Branch profusely; feed into pulmonary capillary networks Pulmonary veins carry oxygenated blood from respiratory zones to heart © 2013 Pearson Education, Inc.

Bronchial arteries provide oxygenated blood to lung tissue
Blood Supply Bronchial arteries provide oxygenated blood to lung tissue Arise from aorta and enter lungs at hilum Part of systemic circulation (high pressure, low volume) Supply all lung tissue except alveoli Bronchial veins anastomose with pulmonary veins Pulmonary veins carry most venous blood back to heart © 2013 Pearson Education, Inc.

Visceral pleura on external lung surface
Pleurae Thin, double-layered serosa; divides thoracic cavity into two pleural compartments and mediastinum Parietal pleura on thoracic wall, superior face of diaphragm, around heart, between lungs Visceral pleura on external lung surface Pleural fluid fills slitlike pleural cavity Provides lubrication and surface tension  assists in expansion and recoil © 2013 Pearson Education, Inc.

Heart (in mediastinum) Anterior mediastinum Sternum Anterior
Figure 22.10c Anatomical relationships of organs in the thoracic cavity. Esophagus (in mediastinum) Posterior Vertebra Root of lung at hilum • Left main bronchus Right lung • Left pulmonary artery Parietal pleura • Left pulmonary vein Visceral pleura Left lung Pleural cavity Thoracic wall Pulmonary trunk Pericardial membranes Heart (in mediastinum) Anterior mediastinum Sternum Anterior Transverse section through the thorax, viewed from above. Lungs, pleural membranes, and major organs in the mediastinum are shown. © 2013 Pearson Education, Inc.

Mechanics of Breathing
Pulmonary ventilation consists of two phases Inspiration-gases flow into lungs Expiration-gases exit lungs © 2013 Pearson Education, Inc.

Pressure Relationships in the Thoracic Cavity
Atmospheric pressure (Patm) Pressure exerted by air surrounding body 760 mm Hg at sea level = 1 atmosphere Respiratory pressures described relative to Patm Negative respiratory pressure-less than Patm Positive respiratory pressure-greater than Patm Zero respiratory pressure = Patm © 2013 Pearson Education, Inc.

Intrapulmonary Pressure
Intrapulmonary (intra-alveolar) pressure (Ppul) Pressure in alveoli Fluctuates with breathing Always eventually equalizes with Patm © 2013 Pearson Education, Inc.

Intrapleural Pressure
Intrapleural pressure (Pip) Pressure in pleural cavity Fluctuates with breathing Always a negative pressure (<Patm and <Ppul) Fluid level must be minimal Pumped out by lymphatics If accumulates  positive Pip pressure  lung collapse © 2013 Pearson Education, Inc.

Intrapleural Pressure
Negative Pip caused by opposing forces Two inward forces promote lung collapse Elastic recoil of lungs decreases lung size Surface tension of alveolar fluid reduces alveolar size One outward force tends to enlarge lungs Elasticity of chest wall pulls thorax outward © 2013 Pearson Education, Inc.

Pressure Relationships
If Pip = Ppul or Patm  lungs collapse (Ppul – Pip) = transpulmonary pressure Keeps airways open Greater transpulmonary pressure  larger lungs © 2013 Pearson Education, Inc.

Figure 22.12 Intrapulmonary and intrapleural pressure relationships.
Atmospheric pressure (Patm) 0 mm Hg (760 mm Hg) Parietal pleura Thoracic wall Visceral pleura Pleural cavity Transpulmonary pressure 4 mm Hg (the difference between 0 mm Hg and −4 mm Hg) – 4 Intrapleural pressure (Pip) −4 mm Hg (756 mm Hg) Lung Diaphragm Intrapulmonary pressure (Ppul) 0 mm Hg (760 mm Hg) © 2013 Pearson Education, Inc.

Atelectasis (lung collapse) due to Plugged bronchioles  collapse of alveoli Pneumothorax-air in pleural cavity From either wound in parietal or rupture of visceral pleura Treated by removing air with chest tubes; pleurae heal  lung reinflates © 2013 Pearson Education, Inc.

Pulmonary Ventilation
Inspiration and expiration Mechanical processes that depend on volume changes in thoracic cavity Volume changes  pressure changes Pressure changes  gases flow to equalize pressure © 2013 Pearson Education, Inc.

Relationship between pressure and volume of a gas
Boyle's Law Relationship between pressure and volume of a gas Gases fill container; if container size reduced  increased pressure Pressure (P) varies inversely with volume (V): P1V1 = P2V2 © 2013 Pearson Education, Inc.

Inspiration Active process
Inspiratory muscles (diaphragm and external intercostals) contract Thoracic volume increases  intrapulmonary pressure drops (to 1 mm Hg) Lungs stretched and intrapulmonary volume increases Air flows into lungs, down its pressure gradient, until Ppul = Patm © 2013 Pearson Education, Inc.

Changes in lateral dimensions (superior view) Sequence of events
Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 1 Changes in lateral dimensions (superior view) Sequence of events Changes in anterior-posterior and superior-inferior dimensions Inspiratory muscles contract (diaphragm descends; rib cage rises). 1 Ribs are elevated and sternum flares as external intercostals contract. Thoracic cavity volume increases. 2 Lungs are stretched; intrapulmonary volume increases. 3 Inspiration External intercostals contract. Intrapulmonary pressure drops (to –1 mm Hg). 4 Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure). 5 Diaphragm moves inferiorly during contraction. © 2013 Pearson Education, Inc.

Changes in anterior-posterior and superior-inferior dimensions
Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 2 Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Inspiratory muscles contract (diaphragm descends; rib cage rises). 1 Ribs are elevated and sternum flares as external intercostals contract. Inspiration External intercostals contract. Diaphragm moves inferiorly during contraction. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 3 Changes in lateral dimensions (superior view) Sequence of events Changes in anterior-posterior and superior-inferior dimensions Inspiratory muscles contract (diaphragm descends; rib cage rises). 1 Ribs are elevated and sternum flares as external intercostals contract. Thoracic cavity volume increases. 2 Inspiration External intercostals contract. Diaphragm moves inferiorly during contraction. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 4 Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Inspiratory muscles contract (diaphragm descends; rib cage rises). 1 Ribs are elevated and sternum flares as external intercostals contract. Thoracic cavity volume increases. 2 Lungs are stretched; intrapulmonary volume increases. 3 Inspiration External intercostals contract. Diaphragm moves inferiorly during contraction. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 5 Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Inspiratory muscles contract (diaphragm descends; rib cage rises). 1 Ribs are elevated and sternum flares as external intercostals contract. Thoracic cavity volume increases. 2 Lungs are stretched; intrapulmonary volume increases. 3 Inspiration External intercostals contract. Intrapulmonary pressure drops (to –1 mm Hg). 4 Diaphragm moves inferiorly during contraction. © 2013 Pearson Education, Inc.

descends; rib cage rises).
Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (1 of 2) Slide 6 Inspiratory muscles contract (diaphragm descends; rib cage rises). Thoracic cavity volume increases. Lungs are stretched; intrapulmonary volume Intrapulmonary pressure drops (to –1 mm Hg). Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure). Inspiration Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) 1 2 3 4 5 Diaphragm moves inferiorly during contraction. Ribs are elevated and sternum flares as external intercostals contract. External © 2013 Pearson Education, Inc.

Quiet expiration normally passive process
Inspiratory muscles relax Thoracic cavity volume decreases Elastic lungs recoil and intrapulmonary volume decreases  pressure increases (Ppul rises to +1 mm Hg)  Air flows out of lungs down its pressure gradient until Ppul = 0 Note: forced expiration-active process; uses abdominal (oblique and transverse) and internal intercostal muscles © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 1 Changes in lateral dimensions (superior view) Sequence of events Changes in anterior-posterior and superior-inferior dimensions Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Thoracic cavity volume decreases. 2 Elastic lungs recoil passively; intrapulmonary Volume decreases. 3 Expiration External intercostals relax. Intrapulmonary pressure rises (to +1 mm Hg). 4 Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0. 5 Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 2 Changes in lateral dimensions (superior view) Sequence of events Changes in anterior-posterior and superior-inferior dimensions Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Expiration External intercostals relax. Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 3 Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Thoracic cavity volume decreases. 2 Expiration External intercostals relax. Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 4 Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Sequence of events Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Thoracic cavity volume decreases. 2 Elastic lungs recoil passively; intrapulmonary Volume decreases. 3 Expiration External intercostals relax. Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 5 Sequence of events Changes in anterior-posterior and superior-inferior dimensions Changes in lateral dimensions (superior view) Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Thoracic cavity volume decreases. 2 Elastic lungs recoil passively; intrapulmonary Volume decreases. 3 Expiration External intercostals relax. Intrapulmonary pressure rises (to +1 mm Hg). 4 Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Figure Changes in thoracic volume and sequence of events during inspiration and expiration. (2 of 2) Slide 6 Changes in lateral dimensions (superior view) Sequence of events Changes in anterior-posterior and superior-inferior dimensions Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). 1 Ribs and sternum are depressed as external intercostals relax. Thoracic cavity volume decreases. 2 Elastic lungs recoil passively; intrapulmonary Volume decreases. 3 Expiration External intercostals relax. Intrapulmonary pressure rises (to +1 mm Hg). 4 Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0. 5 Diaphragm moves superiorly as it relaxes. © 2013 Pearson Education, Inc.

Intrapulmonary pressure. Pressure inside lung
Figure Changes in intrapulmonary and intrapleural pressures during inspiration and expiration. Inspiration Expiration Intrapulmonary pressure. Pressure inside lung decreases as lung volume increases during inspiration; pressure increases during expiration. Intrapulmonary pressure +2 atmospheric pressure (mm Hg) Pressure relative to Trans- pulmonary pressure –2 Intrapleural pressure. Pleural cavity pressure becomes more negative as chest wall expands during inspiration. Returns to initial value as chest wall recoils. –4 –6 Intrapleural pressure –8 Volume of breath. During each breath, the pressure gradients move 0.5 liter of air into and out of the lungs. Volume of breath 0.5 Volume (L) 5 seconds elapsed © 2013 Pearson Education, Inc.

Physical Factors Influencing Pulmonary Ventilation
Three factors hinder air passage and pulmonary ventilation; require energy to overcome Airway resistance Alveolar surface tension Lung compliance © 2013 Pearson Education, Inc.

Relationship between flow (F), pressure (P), and resistance (R) is:
Airway Resistance Friction-major nonelastic source of resistance to gas flow; occurs in airways Relationship between flow (F), pressure (P), and resistance (R) is: ∆P - pressure gradient between atmosphere and alveoli (2 mm Hg or less during normal quiet breathing) Gas flow changes inversely with resistance © 2013 Pearson Education, Inc.

Resistance usually insignificant
Airway Resistance Resistance usually insignificant Large airway diameters in first part of conducting zone Progressive branching of airways as get smaller, increasing total cross-sectional area Resistance greatest in medium-sized bronchi Resistance disappears at terminal bronchioles where diffusion drives gas movement © 2013 Pearson Education, Inc.

Figure 22.15 Resistance in respiratory passageways.
Conducting zone Respiratory zone Medium-sized bronchi Resistance Terminal bronchioles 1 5 10 15 20 23 Airway generation (stage of branching) © 2013 Pearson Education, Inc.

As airway resistance rises, breathing movements become more strenuous Severe constriction or obstruction of bronchioles Can prevent life-sustaining ventilation Can occur during acute asthma attacks; stops ventilation Epinephrine dilates bronchioles, reduces air resistance © 2013 Pearson Education, Inc.

Alveolar Surface Tension
Attracts liquid molecules to one another at gas-liquid interface Resists any force that tends to increase surface area of liquid Water–high surface tension; coats alveolar walls  reduces them to smallest size © 2013 Pearson Education, Inc.

Alveolar Surface Tension
Surfactant Detergent-like lipid and protein complex produced by type II alveolar cells Reduces surface tension of alveolar fluid and discourages alveolar collapse Insufficient quantity in premature infants causes infant respiratory distress syndrome  alveoli collapse after each breath © 2013 Pearson Education, Inc.

Higher lung compliance  easier to expand lungs Normally high due to
Measure of change in lung volume that occurs with given change in transpulmonary pressure Higher lung compliance  easier to expand lungs Normally high due to Distensibility of lung tissue Alveolar surface tension © 2013 Pearson Education, Inc.

Lung Compliance Diminished by
Nonelastic scar tissue replacing lung tissue (fibrosis) Reduced production of surfactant Decreased flexibility of thoracic cage © 2013 Pearson Education, Inc.

Homeostatic imbalances that reduce compliance
Lung Compliance Homeostatic imbalances that reduce compliance Deformities of thorax Ossification of costal cartilage Paralysis of intercostal muscles © 2013 Pearson Education, Inc.

The Respiratory System

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The Respiratory System

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Presentation on theme: "The Respiratory System"— Presentation transcript:

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About project

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