Principles of Anatomy and Physiology Thirteenth Edition Gerard J. Tortora • Bryan H. Derrickson Chapter 23 The Respiratory System Copyright © 2012 by John Wiley & Sons, Inc.

Nose Nasal cavity Pharynx Larynx Trachea Right primary bronchus Lungs (a) Anterior view showing organs of respiration

Trachea Right common carotid artery Thyroid gland Trachea Subclavian artery Right subclavian artery Phrenic nerve Brachiocephalic artery Left common carotid artery Superior vena cava Arch of aorta Rib (cut) Right lung Left lung Heart in pericardial sac Liver Diaphragm (b) Anterior view of lungs and heart after removal of anterolateral thoracic wall and pleura

Bony framework: Frontal bone Nasal bones Maxilla Cartilaginous framework: Lateral nasal cartilages Septal cartilage Alar cartilage Dense fibrous connective and adipose tissue (a) Anterolateral view of external portion of nose showing cartilaginous and bony framework

Opening of auditory tube Maxilla Oral cavity Uvula Tongue Superior Parasagittal plane Nasal meatuses Middle Frontal sinus Inferior Frontal bone Olfactory epithelium Sphenoid bone Sphenoidal sinus Superior Internal naris Middle Nasal conchae Pharyngeal tonsil Inferior Nasal vestibule NASOPHARYNX External naris Opening of auditory tube Maxilla Oral cavity Uvula Tongue Palatine bone Palatine tonsil Soft palate Fauces Lingual tonsil OROPHARYNX Mandible Epiglottis Hyoid bone Ventricular fold (false vocal cord) LARYNGOPHARYNX Regions of the pharynx Esophagus Vocal fold (true vocal cord) Larynx Nasopharynx Thyroid cartilage Oropharynx Trachea Cricoid cartilage Laryngopharynx Thyroid gland (b) Parasagittal section of left side of head and neck showing location of respiratory structures

(c) Frontal section showing conchae Frontal plane Periorbital fat View Ethmoidal cell Eyeball Superior nasal concha Middle nasal concha Nasal septum: Perpendicular plate of ethmoid Inferior nasal concha Vomer Maxillary sinus Hard palate (c) Frontal section showing conchae

1 3 2 4 Anterior view 1. Root: Superior attachment of the nose to the frontal bone 2. Apex: Tip of nose 3. Bridge: Bony framework of nose formed by nasal bones 4. External naris: Nostril; external opening into nasal cavity

Cricotracheal ligament Larynx Thyroid gland Epiglottis Hyoid bone Thyrohyoid membrane Epiglottis: Leaf Stem Corniculate cartilage Thyroid cartilage (Adam’s apple) Arytenoid cartilage Cricothyroid ligament Cricoid cartilage Cricotracheal ligament Thyroid gland Parathyroid glands (4) Tracheal cartilage (a) Anterior view (b) Posterior view

Corniculate cartilage Ventricular fold (false vocal cord) Epiglottis Hyoid bone Thyrohyoid membrane Thyrohyoid membrane Cuneiform cartilage Fat body Corniculate cartilage Ventricular fold (false vocal cord) Arytenoid cartilage Thyroid cartilage Vocal fold (true vocal cord) Laryngeal sinus Cricoid cartilage Cricothyroid ligament Cricotracheal ligament Tracheal cartilage Sagittal plane (c) Sagittal section

Lateral cricoarytenoid muscle Cricotracheal ligament Epiglottic cartilage Cavity of larynx Hyoid bone Vestibule of larynx Thyrohyoid membrane Thyrohyoid muscle Vestibular fold Rima vestibuli Vocal fold Laryngeal sinus Vocalis muscle Thyroid cartilage Inferior pharyngeal constrictor muscle Rima glottidis Sternothyroid muscle Cricoid cartilage Lateral cricoarytenoid muscle Cavity of larynx Cricotracheal ligament Cricothyroid muscle First tracheal cartilage Cricothyroid ligaments Trachea Thyroid gland Parathyroid gland (d) Frontal section

cricoarytenoid muscle Corniculate cartilage Tongue Thyroid cartilage Epiglottis Glottis: Cricoid cartilage Vocal folds (true vocal cords) Vocal fold Rima glottidis Ventricular folds (false vocal cords) Arytenoid cartilage Cuneiform cartilage Posterior cricoarytenoid muscle Corniculate cartilage Superior view of cartilages and muscles View through a laryngoscope (a) Movement of vocal folds apart (abduction) Lateral cricoarytenoid muscle (b) Movement of vocal folds together (adduction)

Corniculate cartilage View Larynx Epiglottis Vocal folds (true vocal cords) Rima glottidis Cuneiform cartilage Ventricular folds (false vocal cords) Corniculate cartilage (c) Superior view

Left lateral lobe of thyroid gland Esophagus Trachea ANTERIOR Transverse plane Cartilage of trachea Right lateral lobe of thyroid gland Fibromuscular membrane of trachea (contains trachealis muscle) Left lateral lobe of thyroid gland Esophagus POSTERIOR Superior view of transverse section of thyroid gland, trachea, and esophagus

Left secondary bronchus Right secondary bronchus BRANCHING OF BRONCHIAL TREE Larynx Trachea Primary bronchi Trachea Secondary bronchi Right lung Left lung Tertiary bronchi Visceral pleura Bronchioles Parietal pleura Terminal bronchioles Pleural cavity Location of carina Right primary bronchus Left primary bronchus Left secondary bronchus Right secondary bronchus Left tertiary bronchus Left bronchiole Right tertiary bronchus Right bronchiole Left terminal bronchiole Right terminal bronchiole Cardiac notch Diaphragm Anterior view

Transverse plane Sternum View Left lung Visceral pleura Ascending aorta Superior vena cava Pulmonary arteries Parietal pleura Pulmonary vein Right lung Esophagus Pleural cavity Thoracic aorta Body of T4 Spinal cord LATERAL MEDIAL POSTERIOR Inferior view of transverse section through thoracic cavity showing pleural cavity and pleural membranes

First rib Apex of lung Left lung Base of lung Pleural cavity Pleura (a) Anterior view of lungs and pleurae in thorax

ANTERIOR Apex Superior lobe Horizontal fissure Oblique fissure View (b) View (c) Apex Superior lobe ANTERIOR Horizontal fissure Oblique fissure Oblique fissure Cardiac notch Inferior lobe Inferior lobe Middle lobe POSTERIOR POSTERIOR Base (b) Lateral view of right lung (c) Lateral view of left lung

POSTERIOR View (d) View (e) Apex Superior lobe Oblique fissure Hilum and its contents (root) Horizontal fissure Inferior lobe Cardiac notch Middle lobe Oblique fissure ANTERIOR Base ANTERIOR (d) Medial view of right lung (e) Medial view of left lung

Respiratory bronchioles MICROSCOPIC AIRWAYS Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveolar sacs Alveoli Terminal bronchiole Pulmonary arteriole Pulmonary venule Lymphatic vessel Respiratory bronchiole Elastic connective tissue Alveoli Alveolar ducts Pulmonary capillary Alveolar sac Visceral pleura Alveoli (a) Diagram of portion of lobule of lung

Respiratory bronchiole Terminal bronchiole Blood vessel Respiratory bronchiole Alveolar ducts Alveoli Alveolar sacs Visceral pleura about 30x LM (b) Lung lobule

Capillary endothelium Type I alveolar cell Capillary basement membrane Monocyte Reticular fiber Elastic fiber Type II alveolar (septal) cell Respiratory membrane Alveolus Red blood cell Diffusion of O2 Capillary endothelium Type I alveolar cell Capillary basement membrane Diffusion of CO2 Alveolar macrophage (dust cell) Epithelial basement membrane Alveolus Type I alveolar cell Red blood cell in pulmonary capillary Interstitial space Alveolar fluid with surfactant (a) Section through alveolus showing cellular components (b) Details of respiratory membrane

Type I alveolar (squamous pulmonary epithelial) cell Alveolar macrophage (dust cell) Alveolus Type II alveolar (septal) cell Type I alveolar (squamous pulmonary epithelial) cell Alveolus 1000x LM (c) Details of several alveoli

Piston Pressure gauge Volume = 1 liter Pressure = 1 atm Volume = 1/2 liter Pressure = 2 atm

MUSCLES OF INHALATION MUSCLES OF EXHALATION Sternocleidomastoid Scalenes Internal intercostals External intercostals Diaphragm External oblique Internal oblique Transversus abdominis Rectus abdominis (a) Muscles of inhalation and their actions (left); muscles of exhalation and their actions (right)

Sternum: Exhalation Inhalation Diaphragm: Exhalation Inhalation (b) Changes in size of thoracic cavity during inhalation and exhalation

(c) During inhalation, the ribs move upward and outward like the handle on a bucket

Atmospheric pressure = 760 mmHg Alveolar pressure = 760 mmHg Alveolar pressure = 758 mmHg Intrapleural pressure = 756 mmHg Intrapleural pressure = 754 mmHg 1. At rest (diaphragm relaxed) 2. During inhalation (diaphragm contracting) Atmospheric pressure = 760 mmHg Alveolar pressure = 762 mmHg Intrapleural pressure = 756 mmHg 3. During exhalation (diaphragm relaxing)

During normal quiet inhalation, the diaphragm and external intercostals contract. During labored inhalation, sternocleidomastoid, scalenes, and pectoralis minor also contract. Alveolar pressure increases to 762 mmHg Atmospheric pressure is about 760 mmHg at sea level Thoracic cavity increases in size and volume of lungs expands Thoracic cavity decreases in size and lungs recoil During normal quiet exhalation, diaphragm and external intercostals relax. During forceful exhalation, abdominal and internal intercostal muscles contract. Alveolar pressure decreases to 758 mmHg (a) Inhalation (b) Exhalation

6000 mL 5000 mL 4000 mL 3000 mL 2000 mL 1000 mL LUNG VOLUMES Inhalation 5000 mL INSPIRATORY RESERVE VOLUME 3100 mL (1900 mL) INSPIRATORY CAPACITY 3600 mL (2400 mL) VITAL CAPACITY 4800 mL (3100 mL) TOTAL LUNG CAPACITY 6000 mL (4200 mL) Exhalation 4000 mL 3000 mL TIDAL VOLUME 500 mL EXPIRATORY RESERVE VOLUME 1200 mL (700 mL) 2000 mL End of record Start of record FUNCTIONAL RESIDUAL CAPACITY 2400 mL (1800 mL) 1000 mL RESIDUAL VOLUME 1200 mL (1100 mL) LUNG VOLUMES LUNG CAPACITIES

Systemic tissue cells: PO2 = 40 mmHg PCO2 = 45 mmHg Atmospheric air: PO2 = 159 mmHg PCO2 = 0.3 mmHg CO2 exhaled O2 inhaled Alveolar air: PO2 = 105 mmHg PCO2 = 40 mmHg Alveoli CO2 O2 Pulmonary capillaries (a) External respiration: pulmonary gas exchange To lungs To left atrium Deoxygenated blood: PO2 = 40 mmHg PCO2 = 45 mmHg Oxygenated blood: PO2 = 100 mmHg PCO2 = 40 mmHg To right atrium To tissue cells (b) Internal respiration: systemic gas exchange Systemic capillaries CO2 O2 Systemic tissue cells: PO2 = 40 mmHg PCO2 = 45 mmHg

Pulmonary capillaries Transport of CO2 7% dissolved in plasma 23% as Hb-CO2 70% as HCO3– Transport of CO2 1.5% dissolved in plasma 98.5% as Hb-O2 Alveoli CO2 O2 7% 23% 1.5% 98.5% 70% Pulmonary capillaries O2 (dissolved) HCO3– Hb + O2 CO2 + Hb Hb Hb–O2 Red blood cell Hb–CO2 (a) External respiration: pulmonary gas exchange Plasma CO2 (dissolved) To lungs To left atrium To right atrium To tissue cells (b) Internal respiration: systemic gas exchange Hb–CO2 Hb–O2 Hb O2 Systemic capillaries O2 (dissolved) HCO3– 7% Hb 23% Interstitial fluid 70% 1.5% Systemic tissue cells CO2 O2

Percent saturation of hemoglobin Deoxygenated blood (contracting skeletal muscle) Deoxygenated blood in systemic veins (average at rest) Oxygenated blood in systemic arteries Percent saturation of hemoglobin P (mmHg) O2

Percent saturation of hemoglobin High blood pH (7.6) Normal blood pH (7.4) Percent saturation of hemoglobin Low blood pH (7.2) P (mmHg) O2 (a) Effect of pH on affinity of hemoglobin for oxygen

Percent saturation of hemoglobin Low blood P CO2 Normal blood CO2 P Percent saturation of hemoglobin High blood P (mmHg) O2 (b) Effect of P on affinity of hemoglobin for oxygen CO2

Percent saturation of hemoglobin Low temperature (20°C, 68°F) Normal blood temperature (37°C, 98.6°F) Percent saturation of hemoglobin High temperature (43°C, 110°F) P (mmHg) O2

Percent saturation of hemoglobin Fetal Percent saturation of hemoglobin Maternal P (mmHg) O2

Reverse chloride shift Exhaled CO2 + Hb Hb–CO2 Cl – Cl – Carbonic anhydrase CO2 CO2 CO2 CO2 + H2O H2CO3 HCO3– + H+ HCO3– O2 O2 O2 O2 + Hb–H Hb–O2+ H+ Interstitial fluid Plasma Inhaled Pulmonary capillary wall Red blood cell Alveolus (a) Exchange of O2 and CO2 in pulmonary capillaries (external respiration) Chloride shift Cl – Cl – CO2 + Hb Hb–CO2 + O2 Carbonic anhydrase CO2 CO2 CO2 CO2 + H2O H2CO3 HCO3– + H+ HCO3– O2 O2 O2 O2 + Hb–H Hb–O2 Interstitial fluid Plasma Tissue cell Systemic capillary wall Red blood cell (b) Exchange of O2 and CO2 in systemic capillaries (internal respiration)

Medullary rhythmicity area: Inspiratory area Medulla oblongata Sagittal plane RESPIRATORY CENTER: Midbrain Pneumotaxic area Apneustic area Pons Medullary rhythmicity area: Inspiratory area Medulla oblongata Expiratory area Spinal cord Sagittal section of brain stem

(a) During normal quiet breathing (b) During forceful breathing Activates INSPIRATORY AREA INSPIRATORY AREA ACTIVE EXPIRATORY AREA ACTIVE INACTIVE 2 seconds 3 seconds Internal intercostal and abdominal muscles contract Diaphragm, sternocleidomastoid, and scalene muscles contract Diaphragm and external intercostals contract Diaphragm and external intercostals relax, followed by elastic recoil of lungs Normal quiet inhalation Normal quiet exhalation Forceful inhalation Forceful exhalation (a) During normal quiet breathing (b) During forceful breathing

Medulla oblongata Sensory axons in glossopharyngeal nerve (cranial nerve IX) Internal carotid artery External carotid artery Carotid body Carotid sinus Common carotid artery Sensory axons in vagus nerve (cranial nerve X) Arch of aorta Aortic bodies Heart

Some stimulus disrupts homeostasis by Increasing Arterial blood PCO2 (or decreasing pH or PO2) Receptors Central Chemo- receptors in medulla Peripheral chemo- receptors in aortic and carotid bodies Input Nerve impulses Control center Inspiratory area in medulla oblongata Return to homeostasis when response brings arterial blood PCO2 , pH, and PO2 back to normal Nerve impulses Output Effectors Muscles of inhalation and exhalation contract more forcefully and more frequently (hyperventilation) Decrease in arterial blood PCO2, increase in pH, and increase in PO2

Pharynx Pharynx Respiratory diverticulum Trachea Tracheal bud Esophagus Bronchial buds Esophagus Fourth week

Left primary bronchus Trachea Left secondary bronchi Right primary bronchus Right secondary bronchi Right tertiary bronchi Left tertiary bronchi Fifth week Sixth week

Trachea Right superior lobe Left superior lobe Right middle lobe Left inferior lobe Right inferior lobe Developing pleura Eighth week