Respiratory System PDF

1 Respiratory System Joseph Peter V. Arguillas, MD © 2019 McGraw-Hill Education  2...

1 Respiratory System Joseph Peter V. Arguillas, MD © 2019 McGraw-Hill Education  2 Respiration Respiration includes the following processes: 1. Ventilation, or breathing, which is the movement of air into and out of the lungs 2. The exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood 3. The transport of O2 and CO2 in the blood 4. The exchange of O2 and CO2 between the blood and the tissues. © 2019 McGraw-Hill Education  3 Functions 1. Respiration 2. Regulation of blood pH 3. Voice Production 4. Olfaction 5. Innate Immunity © 2019 McGraw-Hill Education  4 Upper Respiratory Tract External nose Nasal cavity Pharynx © 2019 McGraw-Hill Education  5 Respiratory System 1 Figure 15.1 © 2019 McGraw-Hill Education  6 Nose 1 External nose: composed of mainly of hyaline cartilage Nasal cavity: extends from nares (nostrils) to choane choana: openings to pharynx hard palate is its roof © 2019 McGraw-Hill Education  7 Nose 2 Paranasal sinuses: air filled spaces within bone open into nasal cavity lined with mucous Conchae: on each side of nasal cavity increase surface area of nasal cavity help in cleaning, humidifying, warming of air © 2019 McGraw-Hill Education  8 Nose 3 Nasolacrimal ducts: carry tears from eyes open into nasal cavity © 2019 McGraw-Hill Education  9 Functions of the Nose Filters Airway for respiration Involved in speech Olfactory receptors Warms air Sneezing dislodges materials from nose © 2019 McGraw-Hill Education  10 Pharynx 1 Pharynx: a common passageway for the respiratory and digestive systems Nasopharynx: takes in air Oropharynx: extends from uvula to epiglottis takes in food, drink, and air Laryngopharynx: extends from epiglottis to esophagus food and drink pass through © 2019 McGraw-Hill Education  11 Pharynx 2 Uvula: “little grape” extension of soft palate Pharyngeal tonsil: aids in defending against infections © 2019 McGraw-Hill Education  12 Nasal Cavity and Pharynx Figure 15.2a © 2019 McGraw-Hill Education  13 Lower Respiratory Tract Larynx – lower portions of Trachea Bronchi Lungs © 2019 McGraw-Hill Education  14 Respiratory System 2 Figure 15.1 © 2019 McGraw-Hill Education  15 Larynx 1 Located in the anterior throat and extends from the base of the tongue to the trachea Consists of cartilages Thyroid cartilage: largest piece of cartilage called Adam’s apple © 2019 McGraw-Hill Education  16 Larynx 2 Epiglottis: piece of cartilage flap that prevents swallowed materials from entering larynx © 2019 McGraw-Hill Education  17 Larynx 3 Vocal folds/cords: source of voice production air moves past them, they vibrate, and sound is produced force of air determine loudness tension determines pitch Laryngitis: inflammation of vocal folds caused by overuse, dry air, infection © 2019 McGraw-Hill Education  18 Anatomy of the Larynx Figure 15.3 © 2019 McGraw-Hill Education  19 Vestibular and Vocal Folds Figure 15.4 © 2019 McGraw-Hill Education (b) ©CNRI/Science Source  20 Trachea Windpipe Consists of 16 to 20 C-shaped pieces of cartilage Contains cilia pseudostratified columnar epi. Smoking kills cilia Coughing dislodges materials from trachea Divides into right and left primary bronchi (lungs) © 2019 McGraw-Hill Education  21 Bronchi Divide from trachea Connect to lungs Lined with cilia Contain C-shaped pieces of cartilage © 2019 McGraw-Hill Education  22 Lungs Primary organ of respiration Cone shaped The base rests on the diaphragm The apex extends above the clavicle Right lung has 3 lobes Left lung has 2 lobes Contains many air passageways (divisions) © 2019 McGraw-Hill Education  23 Lung Airway Passages 1 1. Primary bronchi 2. Lobar (secondary) bronchi 3. Segmental (tertiary) bronchi 4. Bronchioles 5. Terminal bronchioles 6. Respiratory bronchioles 7. Alveolar ducts 8. Alveoli Structures become smaller and more numerous from primary bronchi to alveoli © 2019 McGraw-Hill Education  24 Anatomy of the Trachea and Lungs Figure 15.5 © 2019 McGraw-Hill Education  25 Lungs, Lung Lobes, and Bronchi Figure 15.6 © 2019 McGraw-Hill Education  26 Lung Airway Passages 2 Alveoli: small air sacs where gas exchange occurs surrounded by capillaries 300 million in lungs Asthma attack: contraction of terminal bronchioles leads to reduced air flow © 2019 McGraw-Hill Education  27 Bronchioles and Alveoli Figure 15.7 © 2019 McGraw-Hill Education  28 Respiratory Membrane In lungs where gas exchange between air and blood occurs Formed by walls of alveoli and capillaries Alveolar ducts and respiratory bronchioles also contribute Very thin for diffusion of gases © 2019 McGraw-Hill Education  29 Layers of Respiratory Membrane Thin layer of fluid from alveolus Alveolar epithelium (simple squamous) Basement membrane of alveolar epithelium Thin interstitial space Basement membrane of capillary endothelium Capillary endothelium (simple squamous) © 2019 McGraw-Hill Education  30 Alveolus and the Respiratory Membrane Figure 15.8 © 2019 McGraw-Hill Education  31 Pleural Membranes and Cavities Pleura: double-layered membrane around lungs Parietal pleura: membrane that lines thoracic cavity Visceral pleura: membrane that covers lung’s surface Pleural cavity: space around each lung © 2019 McGraw-Hill Education  32 Pleural Cavities and Membranes Figure 15.9 © 2019 McGraw-Hill Education  33 Ventilation Ventilation (breathing): a process of moving air in and out of the lungs uses the diaphragm, which is a skeletal muscle that separates the thoracic and abdominal cavities © 2019 McGraw-Hill Education  34 Phases of Ventilation Inspiration: breathe in uses the diaphragm and the external intercostal muscles Expiration: breathe out uses the diaphragm Forceful expiration: uses internal intercostal muscles © 2019 McGraw-Hill Education  35 Effect of the Muscles of Respiration on Thoracic Volume Figure 15.10 © 2019 McGraw-Hill Education  36 Pressure Changes and Air Flow When thoracic cavity volume increases pressure decreases When thoracic cavity volume decreases pressure increases Air flows from areas of high to low pressure © 2019 McGraw-Hill Education  37 Inspiration Diaphragm descends and rib cage expands Thoracic cavity volume increases, pressure decreases Atmospheric pressure is greater than (high) alveolar pressure (low) Air moves into alveoli (lungs) © 2019 McGraw-Hill Education  38 Expiration Diaphragm relaxes and rib cage recoils Thoracic cavity volume decreases, pressure increases Alveolar pressure is greater than (high) atmospheric pressure (low) Air moves out of lungs © 2019 McGraw-Hill Education  39 Inspiration and Expiration Pressure Changes Figure 15.11 © 2019 McGraw-Hill Education  40 Lung Recoil Lung recoil: is the tendency for an expanded lung to decrease in size occurs during quiet expiration is due to elastic fibers and thin film of fluid lining alveoli © 2019 McGraw-Hill Education  41 Surfactant Surfactant: a mixture of lipoproteins is produced by secretory cells of the alveoli is a single fluid layer on the surface of thin fluid lining alveoli reduces surface tension keeps lungs from collapsing © 2019 McGraw-Hill Education  42 Pleural Pressure Pleural pressure is: pressure in the pleural cavity less than alveolar pressure keep the alveoli from collapsing © 2019 McGraw-Hill Education  43 Factors that Influence Pulmonary Ventilation Lung elasticity: lungs need to recoil between ventilations decreased by emphysema Lung compliance: expansion of thoracic cavity affected if rib cage is damaged Respiratory passageway resistance: occurs during an asthma attack, infection, tumor © 2019 McGraw-Hill Education  44 Pulmonary Volumes 1 Spirometer: device that measures pulmonary volumes Tidal volume (TV): volume of air inspired and expired during quiet breathing Inspiratory reserve volume (IRV): volume of air that can be inspired forcefully after a normal inspiration © 2019 McGraw-Hill Education  45 Pulmonary Volumes 2 Expiratory reserve volume (ERV): volume of air that can be expired forcefully after a normal expiration Residual volume (RV): volume of air remaining in lungs after a maximal expiration (can’t be measured with spirometer) © 2019 McGraw-Hill Education  46 Pulmonary Volumes 3 Vital capacity (VC): max. amount of air a person can expire after a max. inspiration VC = IRV + ERV + TV Total lung capacity (TLC): TLC = VC + RV © 2019 McGraw-Hill Education  47 Respiratory Volumes and Respiratory Capacities Figure 15.12 © 2019 McGraw-Hill Education  48 Factors that Influence Pulmonary Volumes Gender Age Height Weight © 2019 McGraw-Hill Education  49 Gas Exchange 1 Respiratory membrane: where gas exchange between blood and air occurs primarily alveoli some in respiratory bronchioles and alveolar ducts © 2019 McGraw-Hill Education  50 Gas Exchange 2 Respiratory membrane: does NOT occur in bronchioles, bronchi, trachea influenced by thickness of membrane, total area of membrane, partial pressure of gases © 2019 McGraw-Hill Education  51 Respiratory Membrane Thickness Increased thickness decreases rate of diffusion Pulmonary edema decreases diffusion Rate of gas exchange is decreased O2 exchange is affected before CO2 because CO2 diffuse more easily than O2 © 2019 McGraw-Hill Education  52 Respiratory Membrane Surface Area Total surface area is 70 square meters (basketball court) Decreased due to removal of lung tissue, destruction from cancer, emphysema © 2019 McGraw-Hill Education  53 Partial Pressure Partial pressure: the pressure exerted by a specific gas in a mixture of gases the total atmospheric pressure of all gases at sea level is 760 mm Hg the atmosphere is 21% O2 the partial pressure for O2 is 160 mm Hg the upper case letter P represents partial pressure of a certain gas (Po2) © 2019 McGraw-Hill Education  54 Diffusion of Gases in Lungs Cells in body use O2 and produce CO2. Blood returning from tissues and entering lungs has a decreased Po2 and increased Pco2 O2 diffuses from alveoli into pulmonary capillaries (blood) CO2 diffuses from capillaries into alveoli © 2019 McGraw-Hill Education  55 Gas Exchange Figure 15.13 © 2019 McGraw-Hill Education  56 Diffusion of Gases in Tissues Blood flow from lungs through left side of heart to tissue capillaries Oxygen diffuses from capillaries into interstitial fluid because Po2 in interstitial fluid is lower than capillary Oxygen diffuses from interstitial fluid into cells (Po2) is less © 2019 McGraw-Hill Education  57 Gas Exchange in the Tissues Figure 15.14a © 2019 McGraw-Hill Education  58 Gas Exchange in the Lungs Figure 15.14b © 2019 McGraw-Hill Education  59 Carbon Dioxide Transport and Blood pH 1 CO2 diffuses from cells into capillaries CO2 enters blood and is transported in plasma, combined with blood proteins, bicarbonate ions CO2 reacts with water to form carbonic acid CO2 + H2O H2CO3 bicarbonate ions dissociate into a hydrogen ion and a bicarbonate ion H2CO3 H+ + HCO3- © 2019 McGraw-Hill Education  60 Carbon Dioxide Transport and Blood pH 2 Carbonic anhydrase (RBC) increases rate of CO2 reacting with water CO2 levels increase blood pH decreases © 2019 McGraw-Hill Education  61 Rhythmic Ventilation Normal respiratory rate is 12 to 20 respirations per minute (adults). In children, the rates are higher and may vary from 20 to 40 per minute. The rhythm is controlled by neurons in the medulla oblongata. Rate is determined by the number of times respiratory muscles are stimulated. © 2019 McGraw-Hill Education  62 Respiratory Structures in the Brainstem Figure 15.15 © 2019 McGraw-Hill Education  63 Nervous Control of Breathing Higher brain centers allow voluntary breathing Emotions and speech affect breathing Hering-Breuer Reflex: inhibits respiratory center when lungs are stretched during inspiration © 2019 McGraw-Hill Education  64 Nervous and Chemical Mechanisms of Breathing Figure 15.16 © 2019 McGraw-Hill Education  65 Chemical Control of Breathing Chemoreceptors in medulla oblongata respond to changes in blood pH Blood pH are produced by changes in blood CO2 levels An increase in CO2 causes decreased pH, result is increased breathing Low blood levels of O2 stimulate chemoreceptors in carotid and aortic bodies, increased breathing © 2019 McGraw-Hill Education  66 Regulation of Blood pH Figure 15.17 © 2019 McGraw-Hill Education  67 © 2019 McGraw-Hill Education