Nasal cavity Oral cavity Nostril Pharynx

Larynx

Trachea

Left main Right main (primary) (primary) bronchus bronchus Left lung Right lung

Diaphragm

© 2018 Pearson Education, Inc. 1

Cribriform plate of ethmoid bone Sphenoidal sinus Frontal sinus Posterior nasal aperture Nasal cavity • Nasal conchae (superior, Nasopharynx middle, and inferior) • Pharyngeal tonsil • Nasal meatuses (superior, middle, and inferior) • Opening of pharyngotympanic • Nasal vestibule tube • Nostril • Uvula Hard palate Oropharynx • Palatine tonsil Soft palate

• Lingual tonsil Tongue

Laryngopharynx Hyoid bone

Larynx Esophagus • Epiglottis • Thyroid cartilage Trachea • Vocal fold • Cricoid cartilage (b) Detailed anatomy of the upper respiratory tract © 2018 Pearson Education, Inc. 2 Pharynx • Nasopharynx • Oropharynx • Laryngopharynx

(a) Regions of the pharynx

© 2018 Pearson Education, Inc. 3

Posterior Mucosa

Esophagus Submucosa Trachealis Lumen of Seromucous muscle trachea gland in submucosa Hyaline cartilage Adventitia (a) Anterior © 2018 Pearson Education, Inc. 4 Intercostal muscle Rib Parietal pleura Lung Pleural cavity Trachea Visceral pleura Thymus

Apex of lung Left superior lobe Right superior lobe Oblique Horizontal fissure fissure Right middle lobe Left inferior lobe Oblique fissure Right inferior lobe Heart (in pericardial cavity of mediastinum) Diaphragm Base of lung (a) Anterior view. The lungs flank mediastinal structures laterally.

© 2018 Pearson Education, Inc. 5

Posterior Vertebra Esophagus (in posterior mediastinum) Root of lung at hilum Right lung • Left main bronchus Parietal pleura • Left pulmonary artery • Left pulmonary vein Visceral pleura

Pleural cavity Left lung Thoracic wall Pulmonary trunk Pericardial membranes Heart (in mediastinum) Sternum Anterior mediastinum Anterior (b) Transverse section through the thorax, viewed from above

© 2018 Pearson Education, Inc. 6 Alveolar duct Alveoli

Respiratory bronchioles Alveolar duct

Terminal bronchiole Alveolar sac

(a) Diagrammatic view of respiratory bronchioles, alveolar ducts, and alveoli

© 2018 Pearson Education, Inc. 7

Alveolar duct Alveolar pores

Alveolus

(b) Light micrograph of human lung tissue, showing the final divisions of the respiratory tree (120×)

© 2018 Pearson Education, Inc. 8 Red blood cell Endothelial cell nucleus Capillary

Alveolar pores

Capillary O2 CO2 Macrophage Alveolus Nucleus of squamous epithelial cell Respiratory Alveolar epithelium membrane Fused basement membranes Capillary endothelium Alveoli Red blood Surfactant- Squamous (gas-filled cell in secreting cell epithelial cell air spaces) capillary of alveolar wall

© 2018 Pearson Education, Inc. 9

Changes in anterior-posterior and Changes in lateral superior-inferior dimensions dimensions

Ribs are elevated as external intercostals contract External Full inspiration intercostal (External muscles intercostals contract)

Diaphragm moves inferiorly during contraction (a) Inspiration: Air (gases) flows into the lungs

© 2018 Pearson Education, Inc. 10 Changes in anterior-posterior and Changes in lateral superior-inferior dimensions dimensions

Ribs are depressed as external intercostals relax

Expiration External intercostal (External muscles intercostals relax)

Diaphragm moves superiorly as it relaxes (b) Expiration: Air (gases) flows out of the lungs © 2018 Pearson Education, Inc. 11

+2 Inspiration Expiration

Intrapulmonary +1 pressure

0

–1 Pressure relative Pressure –2 toatmospheric pressure (a) Volume of breath 0.5

0 Volume (L)

–0.5 (b) © 2018 Pearson Education, Inc. 12 6,000

5,000 Inspiratory reserve volume 4,000 3,100 ml Vital capacity 3,000 4,800 ml Total lung Tidal volume 500 ml capacity

Milliliters (ml) Expiratory 6,000 ml 2,000 reserve volume 1,200 ml 1,000 Residual volume 1,200 ml 0

© 2018 Pearson Education, Inc. 13

© 2018 Pearson Education, Inc. 14 Inspired air: Alveoli of lungs:

CO2 O2 O2 CO2 O2 CO2

External respiration

Pulmonary Alveolar Pulmonary arteries capillaries veins

Blood Blood leaving leaving tissues and lungs and entering entering lungs: tissue capillaries:

Heart

O2 CO2 O2 CO2 Tissue capillaries Systemic Systemic veins arteries

Internal respiration CO2 O2

Tissue cells:

O2 CO2 © 2018 Pearson Education, Inc. 15

(a) External respiration in the lungs (pulmonary gas exchange)

Oxygen is loaded into the blood, and carbon dioxide is unloaded.

Alveoli (air sacs)

O2 CO2

Loading

of O2 Unloading of CO2

Hb + O HbO - + 2 2 HCO3 + H H2CO3 CO2 + H2O (Oxyhemoglobin Bicar- Carbonic Water is formed) bonate acid ion Plasma

Red blood cell

Pulmonary capillary © 2018 Pearson Education, Inc. 16 (b) Internal respiration in the body tissues (systemic capillary gas exchange)

Oxygen is unloaded and carbon dioxide is loaded into the blood.

Tissue cells

CO2 O2

Loading Unloading of CO2 of O2

+ - CO2 + H2O H2CO3 H + HCO3 Water Carbonic Bicar- acid bonate HbO2 Hb + O2 Plasma ion

Systemic capillary

Red blood cell

© 2018 Pearson Education, Inc. 17

Breathing control centers: • Pons centers • Medulla centers

Afferent Efferent nerve impulses from impulses to medulla trigger contraction of medulla inspiratory muscles: • Phrenic nerves • Intercostal nerves Breathing control centers stimulated by:

+ CO2 and H increase Nerve impulse in tissue. from O sensor Intercostal 2 muscles indicating O2 decrease Diaphragm

O2 sensor in aortic body of aortic arch

© 2018 Pearson Education, Inc. 18