Chapter 25 Respiratory System

Upper respiratory tract Fig. 25.1 Upper respiratory tract Sinuses Nasal cavity Pharynx Lower respiratory tract Larynx Trachea Bronchi Lungs Sphenoidal sinus Frontal sinus Nasal cavity Upper respiratory tract Pharynx Larynx Trachea Lower respiratory tract Bronchi Lungs Pleura Diaphragm

Conducting portion transports air Fig. 25.1 Conducting portion transports air Nose, nasal cavity, pharynx, larynx, trachea, airways Respiratory portion does gas exchange respiratory bronchioles, alveolar ducts, alveoli (air sacs) Sphenoidal sinus Frontal sinus Nasal cavity Upper respiratory tract Pharynx Larynx Trachea Lower respiratory tract Bronchi Lungs Pleura Diaphragm

External Respiration Internal Respiration Exchange of gases between atmosphere and blood inhalation of air diffusion into blood Exchange of gases between blood and cells of the body transport from lungs to body and back

Other Functions Gas conditioning Sound production Olfaction Defense warming humidifying cleansing of particulates Sound production Olfaction Defense

Lungs surrounded by pleura Fig. 25.10 Lungs surrounded by pleura simple squamous epithelium called mesothelium Outer surface is parietal pleura Inner surface (contact with lung) is visceral pleura Pleural cavity divides pleural layers, has thin layer of fluid Parietal pleura Visceral pleura Pleural cavity Parietal pleura Pleural cavity Visceral pleura Diaphragm

Fig. 25.11 Apex Superior lobe Horizontal fissure Oblique fissure Middle lobe Cardiac notch Inferior lobe Lingula Base Right lung Left lung (a) Lateral views

Fig. 25.11 Apex Superior lobe Oblique fissure Pulmonary artery Main bronchus Hilum Pulmonary veins Root of the lung Horizontal fissure Cardiac impression Middle lobe Cardiac notch Inferior lobe Oblique fissure Oblique fissure Base Lingula Right lung Left lung (b) Medial views

Nasal cavity includes nasal conchae (bony ridges) Fig. 25.2 Superior nasal concha Superior meatus Middle nasal concha Middle meatus Nasal cavity Nasal cavity Inferior meatus Inferior nasal concha Vestibule Nostril Hard palate Nasal cavity includes nasal conchae (bony ridges) Divide nasal cavity into 3 air passages called nasal meatus Create turbulence, slow air passage, ensure air is warmed and humidified Vestibule is area behind nostrils

Hard palate is bottom of nasal cavity Fig. 25.2 Superior nasal concha Superior meatus Middle nasal concha Middle meatus Nasal cavity Nasal cavity Inferior meatus Inferior nasal concha Vestibule Nasal cavity is lined with pseudostratified ciliated columnar epithelium with goblet cells produce mucus highly vascularized Nostril Hard palate Hard palate is bottom of nasal cavity Nasal septum divides right and left sides

Paranasal sinuses named for bone Fig. 25.2 Frontal sinus Paranasal sinuses named for bone frontal sinus housed in frontal bone sphenoidal sinus housed in sphenoid bone maxillary sinuses housed in maxillary bone Paranasal sinuses Sphenoidal sinus

Fig. 25.3 Frontal Ethmoidal Sphenoidal Maxillary Copyright © McGraw-Hill Education. Permission required for reproduction or display. Frontal Ethmoidal Sphenoidal Maxillary

Pharynx = throat divided into 3 parts Fig. 25.2 Pharynx = throat divided into 3 parts pathway for food and air until epiglottis Nasopharynx usually for air only soft palate blocks food from mouth lined with pseudostratified ciliated columnar epithelium Oropharynx pathway for air and food lined with non-keratinized stratified squamous epithelium Laryngopharynx extends from hyoid bone to larynx and esophagus (b) Regions of pharynx Pharynx: Nasopharynx Oropharynx Laryngopharynx

Auditory tube opens into nasopharynx Soft palate lifts to block passage of food to nasal cavity during swallowing Fig. 25.2 Opening of auditory tube Soft palate Uvula Nasopharynx Pharynx Oropharynx Laryngopharynx Palatine tonsil Lingual tonsil

Tonsils provide first line of defense in immune system Fig. 25.2 Tonsils provide first line of defense in immune system Pharyngeal tonsil Nasopharynx Pharynx Oropharynx Laryngopharynx Palatine tonsil Lingual tonsil

Epiglottis flips down during swallowing to cover opening to trachea Food passes down esophagus Fig. 25.2 Nasopharynx Pharynx Oropharynx Laryngopharynx Epiglottis Esophagus Thyroid cartilage Larynx Trachea Cricoid cartilage

Larynx is voice box Air passage Produces sound Fig. 25.2 Epiglottis Thyroid cartilage Cricoid cartilage

Opening to larynx is laryngeal inlet 9 pieces of cartilage Fig. 25.4 Opening to larynx is laryngeal inlet 9 pieces of cartilage held in place by ligaments and muscles Thyroid cartilage is largest front has v-shaped projection called laryngeal prominence creates Adam’s apple Epiglottis Hyoid bone Thyrohyoid membrane (extrinsic) Thyroid cartilage Thyrohyoid muscle (extrinsic) Laryngeal prominence Cricothyroid muscle (extrinsic) Cricoid cartilage Cricotracheal ligament (extrinsic) Trachea (a) Anterior view

Kept open by tracheal cartilage rings Fig. 25.6 Trachea = windpipe Kept open by tracheal cartilage rings C-shaped connected by ligaments open ends connected by trachealis muscle and elastic, ligamentous membrane pushes against trachea during swallowing contracts during coughing; decreases diameter of trachea, increases speed of airflow Esophagus Larynx Thyroid cartilage Cricoid cartilage Trachea Tracheal cartilage Anular ligament Right main bronchus Left main bronchus

Tracheotomy Trachea Thyroid cartilage Tracheotomy tube Cricoid gland Scalpel Incision Suprasternal notch Sutures 1 Incision is made superior to suprasternal notch. Thyroid may have to be cut as well. 2 Retractors separate the tissue, and an incision is made through the third and fourth tracheal rings. 3 A tracheotomy tube is inserted, and the remaining incision is sutured closed.

Trachea cross-section Fig. 25.6 Posterior Esophagus Trachea cross-section Lined with pseudostratified ciliated columnar epithelium goblet cells secrete mucin cilia propels mucus and dust toward larynx and pharynx for swallowing Trachealis muscle Lumen of trachea Mucosa Submucosa Tracheal cartilage LM 8x Anterior

Trachea cross-section Mucosa Trachea cross-section Fig. 25.6 Pseudostratified ciliated columnar epithelium Lamina propria LM 8x Anterior Posterior Submucosa Mucosa Lumen of trachea Trachealis muscle Esophagus Tracheal cartilage Basement membrane Submucosa Mucus Lumen (d) Lined with pseudostratified ciliated columnar epithelium goblet cells secrete mucin cilia propels mucus and dust toward larynx and pharynx for swallowing

Trachea splits at sternal angle into left and right main bronchi Fig. 25.6 Right main bronchus Left main Carina (internal projection) Trachea Trachea splits at sternal angle into left and right main bronchi

Fig. 25.7 Main bronchi Lobar bronchi Larynx Segmental bronchi Smaller bronchi Larynx Trachea (b) Right main bronchus Left main bronchus Right lobar bronchus Left lobar bronchus Right segmental bronchus Left segmental bronchus Smaller bronchi Smaller bronchi

Bronchi branch into bronchioles Fig. 25.8 Bronchiole Bronchi branch into bronchioles lined with simple columnar or cuboidal epithelium no cartilage in walls smooth muscle around walls causes bronchoconstriction/ bronchodilation Terminal bronchioles are end of conducting pathway Branch of pulmonary artery Terminal bronchiole Respiratory bronchiole

Asthma causes bronchial constriction Treatment is inhaled steroids Page 769 Asthma causes bronchial constriction Treatment is inhaled steroids Swollen submucosa Mucus Mucosa Mucosa Narrowed airway Submucosa Extra mucous secretion Normal airway Airway during an asthma attack

Terminal bronchioles branch into respiratory bronchioles branch into smaller bronchioles divide into alveolar ducts lined with simple squamous epithelium each ends in alveolar sac Fig. 25.8 Bronchiole Branch of pulmonary artery Terminal bronchiole Pulmonary arteriole Respiratory bronchiole Pulmonary capillary beds Alveolar duct Branch of pulmonary vein Alveoli Alveolar pores Pulmonary venule Interalveolar septum Alveolar sac Elastic fibers Connective tissue

Each alveolus is ¼ to ½ mm diameter Thin wall promotes gas diffusion Alveolar pores are holes between adjacent alveoli promote gas diffusion Fig. 25.8 Bronchiole Branch of pulmonary artery Terminal bronchiole Pulmonary arteriole Respiratory bronchiole Pulmonary capillary beds Alveolar duct Branch of pulmonary vein Alveoli Alveolar pores Pulmonary venule Interalveolar septum Alveolar sac Elastic fibers Connective tissue

Fig. 25.8 Respiratory bronchiole Alveolar sac Terminal bronchiole ducts Respiratory bronchiole Alveolar duct Alveoli Alveoli Fig. 25.8 LM 60x SEM 180x (b) (c)

Pulmonary capillaries run between alveoli Fig. 25.9 Pulmonary capillaries run between alveoli Type I cells promote gas diffusion Type II cells secrete surfactant reduces surface tension in fluid lining alveolua Macrophages consume foreign objects Erythrocyte Pulmonary capillaries Alveolar type I cell Alveolar type II cell Alveolar macrophages Alveolar pores Interalveolar septum (a)

Fig. 25.9 Nucleus of capillary endothelial cell Nucleus of alveolar type I cell Interalveolar septum Erythrocyte Capillary Diffusion of CO2 Diffusion of O2 Alveolus Alveolar epithelium Fused basement membranes of the alveolar epithelium and the capillary endothelium Respiratory membrane Capillary endothelium (b)

© Collection CNRI/Phototake Copyright © McGraw-Hill Education. Permission required for reproduction or display. Page 764 Left lung Chest x-ray of a patient with pneumonia in the left lung. A normal lung appears as a black space on an x-ray because its spongy structure is not dense. In contrast, a pneumonia lung appears white or opaque on an x-ray due to accumulation of fluid and cells. © Collection CNRI/Phototake

Page 764 Thickened alveolar walls Fluid and leukocytes in alveoli Respiratory bronchiole Alveolar duct Alveoli LM 30x LM 75x Normal lung tissues. Tissues within a lung affected by pneumonia.

contain black deposits. Page 770 Nonsmoker’s lungs: Lungs are pink. Alveoli are small, numerous, and well formed. Alveoli Smoker’s lungs: Lungs are blackened. Alveoli are enlarged, less numerous, and contain black deposits. Enlarged alveolus Deposits