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Chapter 13: The Respiratory System .pptx
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- 3. Organs of theRespiratory System • Nasal cavity/ Nose • Pharynx • Larynx • Trachea • Lungs • Bronchi • Alveoli • Diaphragm
- 5. Functional Anatomy ofthe Respiratory System • Gas exchanges between the blood and external environment occur only in the alveoli of the lungs • Upper respiratory tract includes passageways from the nose to larynx • Lower respiratory tract includes passageways from trachea to alveoli ⚬Passageways to the lungs purify, humidify, and warm the incoming air
- 6. The Nose • Theonly externally visible part of the respiratory system ⚬Nostrils (nares) are the route through which air enters the nose ⚬Nasal cavity is the interior of the nose ⚬Nasal septum divides the nasal cavity
- 7. Frontal sinus Oropharynx Trachea Nasal cavity Hyoidbone Cribriform plate of ethmoid bone • Palatine tonsil • Lingual tonsil Laryngopharynx Esophagus • Nasal conchae (superior, middle, and inferior) • Nasal meatuses (superior, middle, and inferior) • Nasal vestibule • Nostril Hard palate Soft palate Tongue Larynx • Epiglottis • Thyroid cartilage • Vocal fold • Cricoid cartilage Sphenoidal sinus Posterior nasal aperture Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section. (b) Detailed anatomy of the upper respiratory tract • Opening of pharyngotympanic tube Nasopharynx • Pharyngeal tonsil • Uvula
- 8. The Nose • Olfactoryreceptors are located in the mucosa on the superior surface • The rest of the cavity is lined with respiratory mucosa, which ⚬Moistens air ⚬Traps incoming foreign particles ⚬Enzymes in the mucus destroy bacteria chemically
- 9. The Nose • Conchaeare projections from the lateral walls ⚬Increase surface area ⚬Increase air turbulence within the nasal cavity ⚬Increased trapping of inhaled particles • The palate separates the nasal cavity from the oral cavity ⚬Hard palate is anterior and supported by bone ⚬Soft palate is posterior and unsupported
- 10. The Nose • Paranasalsinuses ⚬Cavities within the frontal, sphenoid, ethmoid, and maxillary bones surrounding the nasal cavity ⚬Sinuses: ￭ Lighten the skull ￭ Act as resonance chambers for speech ￭ Produce mucus
- 11. The Pharynx • Commonlycalled the throat • Muscular passageway from nasal cavity to larynx ⚬Continuous with the posterior nasal aperture • Three regions of the pharynx 1.Nasopharynx—superior region behind nasal cavity 2.Oropharynx—middle region behind mouth 3.Laryngopharynx—inferior region attached to larynx
- 12. The Pharynx • Oropharynxand laryngopharynx serve as common passageway for air and food ⚬Epiglottis routes food into the posterior tube, the esophagus • Pharyngotympanic tubes open into the nasopharynx ⚬Drain the middle ear
- 13. Pharynx • Laryngopharynx • Nasopharynx •Oropharynx (a) Regions of the pharynx
- 14. The Pharynx • Tonsilsare clusters of lymphatic tissue that play a role in protecting the body from infection ⚬Pharyngeal tonsil (adenoid), a single tonsil, is located in the nasopharynx ⚬Palatine tonsils (2) are located in the oropharynx at the end of the soft palate ⚬Lingual tonsils (2) are found at the base of the tongue
- 15. Frontal sinus Oropharynx Trachea Nasal cavity Hyoidbone Cribriform plate of ethmoid bone • Palatine tonsil • Lingual tonsil Laryngopharynx Esophagus • Nasal conchae (superior, middle, and inferior) • Nasal meatuses (superior, middle, and inferior) • Nasal vestibule • Nostril Hard palate Soft palate Tongue Larynx • Epiglottis • Thyroid cartilage • Vocal fold • Cricoid cartilage Sphenoidal sinus Posterior nasal aperture Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section. (b) Detailed anatomy of the upper respiratory tract • Opening of pharyngotympanic tube Nasopharynx • Pharyngeal tonsil • Uvula
- 16. The Larynx • Commonlycalled the voice box • Functions ⚬Routes air and food into proper channels ⚬Plays a role in speech • Located inferior to the pharynx • Made of eight rigid hyaline cartilages ⚬Thyroid cartilage (Adam’s apple) is the largest
- 17. The Larynx • Epiglottis ⚬Spoon-shapedflap of elastic cartilage ⚬Protects the superior opening of the larynx ⚬Routes food to the posteriorly situated esophagus and routes air toward the trachea ⚬During swallowing, the epiglottis rises and forms a lid over the opening of the larynx
- 18. The Larynx • Vocalfolds (true vocal cords) ⚬Vibrate with expelled air ⚬Allow us to speak • The glottis includes the vocal cords and the opening between the vocal cords
- 19. The Trachea • Commonlycalled the windpipe • 4-inch-long tube that connects to the larynx • Walls are reinforced with C-shaped rings of hyaline cartilage, which keep the trachea patent (open) • Lined with ciliated mucosa ⚬Cilia beat continuously in the opposite direction of incoming air ⚬Expel mucus loaded with dust and other debris away from lungs
- 20. Esophagus Posterior Anterior Trachealis muscle Submucosa Adventitia Hyaline cartilage (a) Mucosa Seromuc ous gland in submuc osa Lumen of trachea Figure13.3a Anatomy of the trachea and esophagus.
- 21. (b) Figure 13.3b Anatomyof the trachea and esophagus.
- 22. The Main Bronchi •Formed by division of the trachea • Each bronchus enters the lung at the hilum (medial depression) • Right bronchus is wider, shorter, and straighter than left • Bronchi subdivide into smaller and smaller branches
- 23. Figure 13.1 Themajor respiratory organs shown in relation to surrounding structures. Nasal cavity Trache a Right main (primary) bronchus Left main (primary) bronchus Nostril Oral cavity Pharynx Larynx Right lung Diaphragm Left lung
- 24. The Lungs • Occupythe entire thoracic cavity except for the central mediastinum • Apex of each lung is near the clavicle (superior portion) • Base rests on the diaphragm • Each lung is divided into lobes by fissures ⚬Left lung—two lobes ⚬Right lung—three lobes
- 25. The Lungs • Serosacovers the outer surface of the lungs ⚬Pulmonary (visceral) pleura covers the lung surface ⚬Parietal pleura lines the walls of the thoracic cavity • Pleural fluid fills the area between layers ⚬Allows the lungs to glide over the thorax ⚬Decreases friction during breathing • Pleural space (between the layers) is more of a potential space
- 26. The Lungs • Thebronchial tree ⚬Main bronchi subdivide into smaller and smaller branches ⚬Bronchial (respiratory) tree is the network of branching passageways ⚬All but the smallest passageways have reinforcing cartilage in the walls ⚬Conduits to and from the respiratory zone ⚬Bronchioles (smallest conducting passageways)
- 27. Figure 13.4a Anatomicalrelationships of organs in the thoracic cavity. Visceral pleura Rib Pleural cavity Left superior lobe Left inferior lobe Obliqu e fissure Thymus Trachea Apex of lung Right superior lobe Horizontal fissure Oblique fissure Right middle lobe Right inferior lobe Heart (in pericardial cavity of mediastinum) Diaphrag m Base of lung Lung Parietal pleura (a) Anterior view. The lungs flank mediastinal structures laterally. Intercostal muscle
- 28. Respiratory Zone Structuresand the Respiratory Membrane • Terminal bronchioles lead into respiratory zone structures and terminate in alveoli • Respiratory zone includes the: ⚬Respiratory bronchioles ⚬Alveolar ducts ⚬Alveolar sacs ⚬Alveoli (air sacs)—the only site of gas exchange • Conducting zone structures include all other passageways
- 29. © 2018 PearsonEducation, Inc. Respiratory bronchioles Terminal bronchiole Alveoli Alveolar duct Alveolar sac Alveolar duct (a) Diagrammatic view of respiratory bronchioles, alveolar ducts, and alveoli Figure 13.5a Respiratory zone structures.
- 30. Alveolar pores Alveolus (b) Light micrographof human lung tissue, showing the final divisions of the respiratory tree (120×) Alveolar duct Figure 13.5b Respiratory zone structures.
- 31. Respiratory Zone Structuresand the Respiratory Membrane • Alveoli ⚬Simple squamous epithelial cells largely compose the walls ⚬Alveolar pores connect neighboring air sacs • Pulmonary capillaries cover external surfaces of alveoli
- 32. Respiratory Zone Structuresand the Respiratory Membrane • Respiratory membrane (air-blood barrier) ⚬On one side of the membrane is air, and on the other side is blood flowing past ⚬Formed by alveolar and capillary walls • Gas crosses the respiratory membrane by diffusion ⚬Oxygen enters the blood ⚬Carbon dioxide enters the alveoli
- 33. Respiratory Zone Structuresand the Respiratory Membrane • Alveolar macrophages (“dust cells”) ⚬Add protection by picking up bacteria, carbon particles, and other debris • Surfactant (a lipid molecule) ⚬Coats gas-exposed alveolar surfaces ⚬Secreted by cuboidal surfactant-secreting cells © 2018 Pearson Education, Inc.
- 34. © 2018 PearsonEducation, Inc. Capillary endothelium Alveolar epithelium Red blood cell Capillary Surfactant- secreting cell Squamous epithelial cell of alveolar wall Endothelial cell nucleus Macrophage Alveoli (gas-filled air spaces) Red blood cell in capillary Alveolar pores Respiratory membrane Capillary Nucleus of squamous epithelial cell Alveolus Fused basement membranes Figure 13.6 Functional anatomy of the respiratory membrane (air-blood barrier). O₂ CO₂
- 35. The Gas ExchangeProcess • Oxygen intake: When you inhale, oxygen-rich air enters the lungs and reaches the alveoli. • Diffusion: Oxygen diffuses through the thin walls of the alveoli into the surrounding capillaries, where it binds to red blood cells.
- 36. The Gas ExchangeProcess • Carbon dioxide removal: At the same time, carbon dioxide, a waste product of cellular metabolism, diffuses out of the capillaries and into the alveoli. • Exhalation: When you exhale, the carbon dioxide-rich air is expelled from the lungs.
- 37. Respiratory Physiology • Functionsof the respiratory system ⚬Supply the body with oxygen ⚬Dispose of carbon dioxide • Respiration includes four distinct events (discussed next) ⚬Pulmonary ventilation ⚬External respiration ⚬Respiratory gas transport ⚬Internal respiration
- 38. Respiratory Physiology • Fourevents of respiration 1.Pulmonary ventilation—moving air into and out of the lungs (commonly called breathing) 2.External respiration—gas exchange between pulmonary blood and alveoli ￭ Oxygen is loaded into the blood ￭ Carbon dioxide is unloaded from the blood
- 39. Respiratory Physiology • Fourevents of respiration (continued) 1.Respiratory gas transport—transport of oxygen and carbon dioxide via the bloodstream 2.Internal respiration—gas exchange between blood and tissue cells in systemic capillaries
- 40. Mechanics of Breathing •Pulmonary ventilation ⚬Mechanical process that depends on volume changes in the thoracic cavity ⚬Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure
- 41. Mechanics of Breathing •Two phases of pulmonary ventilation ⚬Inspiration = inhalation ￭ Flow of air into lungs ⚬Expiration = exhalation ￭ Air leaving lungs
- 42. Mechanics of Breathing •Inspiration (inhalation) ⚬Diaphragm and external intercostal muscles contract ⚬Intrapulmonary volume increases ⚬Gas pressure decreases ⚬Air flows into the lungs until intrapulmonary pressure equals atmospheric pressure
- 43. (a) Inspiration: Air(gases) flows into the lungs Changes in lateral dimensions Changes in anterior-posterior and superior- inferior dimensions Figure 13.7a Rib cage and diaphragm positions during breathing. Ribs are elevated as external intercostals contract External intercosta l muscles Diaphragm moves inferiorly during contraction Full inspiration (External intercostals contract)
- 44. Mechanics of Breathing •Expiration (exhalation) ⚬Largely a passive process that depends on natural lung elasticity ⚬Intrapulmonary volume decreases ⚬Gas pressure increases ⚬Gases passively flow out to equalize the pressure ⚬Forced expiration can occur mostly by contraction of internal intercostal muscles to depress the rib cage
- 45. Mechanics of Breathing •Intrapleural pressure ⚬The pressure within the pleural space) is always negative ⚬Major factor preventing lung collapse ⚬If intrapleural pressure equals atmospheric pressure, the lungs recoil and collapse
- 46. Ribs are depressed asexternal intercostals relax (b) Expiration: Air (gases) flows out of the lungs External intercostal muscles Diaphragm moves superiorly as it relaxes Changes in lateral dimensions Changes in anterior-posterior and superior-inferior dimensions Figure 13.7b Rib cage and diaphragm positions during breathing. Expiration (External intercostals relax)
- 47. Respiratory Volumes andCapacities • Factors affecting respiratory capacity ⚬Size ⚬Sex ⚬Age ⚬Physical condition • Tidal volume (TV) ⚬Normal quiet breathing ⚬500 ml of air is moved in/out of lungs with each breath
- 48. Respiratory Volumes andCapacities • Inspiratory reserve volume (IRV) ⚬Amount of air that can be taken in forcibly over the tidal volume ⚬Usually around 3,100 ml • Expiratory reserve volume (ERV) ⚬Amount of air that can be forcibly exhaled after a tidal expiration ⚬Approximately 1,200 ml
- 49. Respiratory Volumes andCapacities • Residual volume ⚬Air remaining in lung after expiration ⚬Cannot be voluntarily exhaled ⚬Allows gas exchange to go on continuously, even between breaths, and helps keep alveoli open (inflated) ⚬About 1,200 ml
- 50. Respiratory Volumes andCapacities • Vital capacity ⚬The total amount of exchangeable air ⚬Vital capacity = TV + IRV + ERV ⚬4,800 ml in men; 3,100 ml in women • Dead space volume ⚬Air that remains in conducting zone and never reaches alveoli ⚬About 150 ml
- 51. Respiratory Volumes andCapacities • Functional volume ⚬Air that actually reaches the respiratory zone ⚬Usually about 350 ml • Respiratory capacities are measured with a spirometer
- 52. Vital capacity 4,800 ml Totallung capacity 6,000 ml Inspiratory reserve volume 3,100 ml Tidal volume 500 ml Expiratory reserve volume 1,200 ml Residual volume 1,200 ml M i l l i l i t e r s ( m l ) 1,000 2,000 3,000 4,000 5,000 6,000 0 Figure 13.9 Graph of the various respiratory volumes in a healthy young adult male.
- 53. Nonrespiratory Air Movements •Can be caused by reflexes or voluntary actions • Examples ⚬Cough and sneeze—clears lungs of debris ⚬Crying—emotionally induced mechanism ⚬Laughing—similar to crying ⚬Hiccup—sudden inspirations ⚬Yawn—very deep inspiration
- 54. Table 13.1 NonrespiratoryAir (Gas) Movements
- 55. Respiratory Sounds • Soundsare monitored with a stethoscope • Two recognizable sounds can be heard with a stethoscope: 1.Bronchial sounds—produced by air rushing through large passageways such as the trachea and bronchi 2.Vesicular breathing sounds—soft sounds of air filling alveoli
- 56. External Respiration, GasTransport, and Internal Respiration • Gas exchanges occur as a result of diffusion ⚬External respiration is an exchange of gases occurring between the alveoli and pulmonary blood (pulmonary gas exchange) ⚬Internal respiration is an exchange of gases occurring between the blood and tissue cells (systemic capillary gas exchange) • Movement of the gas is toward the area of lower concentration
- 57. External respiration Pulmonary veins Inspired air: Blood leaving tissues and entering lungs: Pulmonary arteries Alveolar capillaries Tissue capillaries Systemic veins Systemic arteries Internal respiration CO₂ O ₂ CO₂ O ₂ Alveoli oflungs: CO₂ O ₂ CO₂ O ₂ CO₂ O ₂ Blood leaving lungs and entering tissue capillaries: Heart CO₂ O ₂ Tissue cells: CO₂ O ₂ Figure 13.10 Gas exchanges in external and internal respiration.
- 58. External Respiration • Oxygenis loaded into the blood ⚬Oxygen diffuses from the oxygen-rich air of the alveoli to the oxygen-poor blood of the pulmonary capillaries • Carbon dioxide is unloaded out of the blood ⚬Carbon dioxide diffuses from the blood of the pulmonary capillaries to the alveoli
- 59. (a) External respirationin 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 O₂ HbO₂ HCO₃ H H₂CO₃ CO₂ H₂O (Oxyhemoglobin is formed) Bicar- bonate ion Carbonic acid Water Red blood cell Pulmonary capillary Plasma Figure 13.11a The loading and unloading of oxygen (O₂) and carbon dioxide (CO₂) in the body.
- 60. Gas Transport inthe Blood • Oxygen transport in the blood ⚬Most oxygen travels attached to hemoglobin and forms oxyhemoglobin (HbO ) ₂ ⚬A small dissolved amount is carried in the plasma
- 61. (a) External respirationin 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 O₂ HbO₂ HCO₃ H H₂CO₃ CO₂ H₂O (Oxyhemoglobin is formed) Bicar- bonate ion Carbonic acid Water Red blood cell Pulmonary capillary Plasma Figure 13.11a The loading and unloading of oxygen (O₂) and carbon dioxide (CO₂) in the body.
- 62. Gas Transport inthe Blood • Carbon dioxide transport in the blood ⚬Most carbon dioxide is transported in the plasma as bicarbonate ion (HCO –) ₃ ⚬A small amount is carried inside red blood cells on hemoglobin, but at different binding sites from those of oxygen
- 63. Gas Transport inthe Blood • For carbon dioxide to diffuse out of blood into the alveoli, it must be released from its bicarbonate form: ⚬Bicarbonate ions enter RBC ⚬Combine with hydrogen ions ⚬Form carbonic acid (H CO ) ₂ ₃ ⚬Carbonic acid splits to form water + CO₂ ⚬Carbon dioxide diffuses from blood into alveoli
- 64. (a) External respirationin 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 O₂ HbO₂ HCO₃ H H₂CO₃ CO₂ H₂O (Oxyhemoglobin is formed) Bicar- bonate ion Carbonic acid Water Red blood cell Pulmonary capillary Plasma Figure 13.11a The loading and unloading of oxygen (O₂) and carbon dioxide (CO₂) in the body.
- 65. Internal Respiration • Exchangeof gases between blood and tissue cells • An opposite reaction from what occurs in the lungs ⚬Carbon dioxide diffuses out of tissue cells to blood (called loading) ⚬Oxygen diffuses from blood into tissue (called unloading)
- 66. (b) Internal respirationin the body tissues (systemic capillary gas exchange) Oxygen is unloaded and carbon dioxide is loaded into the blood. Tissue cells CO₂ O₂ Unloading of O₂ Loading of CO₂ HbO₂ Hb O₂ Water Bicar- bonat e ion Systemic capillary Red blood cell Carboni c acid CO₂ H₂O H₂CO₃ H HCO₃ Plasma Figure 13.11b The loading and unloading of oxygen (O₂) and carbon dioxide (CO₂) in the body.
- 67. Control of Respiration •Neural regulation: setting the basic rhythm ⚬Activity of respiratory muscles is transmitted to and from the brain by phrenic and intercostal nerves ⚬Neural centers that control rate and depth are located in the medulla and pons ￭ Medulla—sets basic rhythm of breathing and contains a pacemaker (self-exciting inspiratory center) called the ventral respiratory group (VRG) ￭ Pons—smoothes out respiratory rate
- 68. Control of Respiration •Normal respiratory rate (eupnea) ⚬12 to 15 respirations per minute • Hyperpnea ⚬Increased respiratory rate, often due to extra oxygen needs
- 69. Breathing control centers: • Ponscenters • Medulla centers Breathing control centers stimulated by: O₂ sensor in aortic body of aortic arch Intercostal muscles CO₂ and H increase in tissue. Nerve impulse from O₂ sensor indicating O₂ decrease Afferent impulses to medulla Efferent nerve impulses from medulla trigger contraction of inspiratory muscles: • Phrenic nerves • Intercostal nerves Figure 13.12 Neural control of respiration. Diaphragm
- 70. Control of Respiration •Non-neural factors influencing respiratory rate and depth ⚬Physical factors ￭ Increased body temperature ￭ Exercise ￭ Talking ￭ Coughing ⚬Volition (conscious control) ⚬Emotional factors such as fear, anger, and excitement
- 71. Control of Respiration •Non-neural factors influencing respiratory rate and depth (continued) ⚬Chemical factors: CO levels ₂ ￭ The body’s need to rid itself of CO is the ₂ most important stimulus for breathing ￭ Increased levels of carbon dioxide (and thus, a decreased or acidic pH) in the blood increase the rate and depth of breathing ￭ Changes in carbon dioxide act directly on the medulla oblongata
- 72. Control of Respiration •Non-neural factors influencing respiratory rate and depth (continued) ⚬Chemical factors: oxygen levels ￭ Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and common carotid artery ￭ Information is sent to the medulla ￭ Oxygen is the stimulus for those whose systems have become accustomed to high levels of carbon dioxide as a result of disease
- 73. Control of Respiration •Non-neural factors influencing respiratory rate and depth (continued) ⚬Chemical factors (continued) ￭ Hyperventilation • Rising levels of CO in the blood (acidosis) result in faster, ₂ deeper breathing • Exhale more CO to elevate blood pH ₂ • May result in apnea and dizziness and lead to alkalosis
- 74. Control of Respiration •Non-neural factors influencing respiratory rate and depth (continued) ⚬Chemical factors (continued) ￭ Hypoventilation • Results when blood becomes alkaline (alkalosis) • Extremely slow or shallow breathing • Allows CO to accumulate in the blood ₂
- 75. Developmental Aspects ofthe Respiratory System • Lungs do not fully inflate until 2 weeks after birth ⚬This change from nonfunctional to functional respiration depends on surfactant ⚬Surfactant lowers surface tension so the alveoli do not collapse ⚬Surfactant is formed late in pregnancy, around 28 to 30 weeks
- 76. Developmental Aspects ofthe Respiratory System • Respiratory rate changes throughout life ⚬Newborns: 40 to 80 respirations per minute ⚬Infants: 30 respirations per minute ⚬Age 5: 25 respirations per minute ⚬Adults: 12 to 18 respirations per minute ⚬Rate often increases again in old age
- 77. Developmental Aspects ofthe Respiratory System • Asthma ⚬Chronically inflamed, hypersensitive bronchiole passages ⚬Respond to irritants with dyspnea, coughing, and wheezing
- 78. Developmental Aspects ofthe Respiratory System • Youth and middle age ⚬Most respiratory system problems are a result of external factors, such as infections and substances that physically block respiratory passageways
- 79. Developmental Aspects ofthe Respiratory System • Aging effects ⚬Elasticity of lungs decreases ⚬Vital capacity decreases ⚬Blood oxygen levels decrease ⚬Stimulating effects of carbon dioxide decrease ⚬Elderly are often hypoxic and exhibit sleep apnea ⚬More risks of respiratory tract infection
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