Chapter 19


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Chapter 19

  1. 1. Biology 248 Anatomy & Physiology II Chapter 19 Vicki Maroon National Institute of Technology
  2. 2. Section 19.1: Introduction <ul><li>The respiratory system consists of passages that filter incoming air and transport it into the body, into the lungs, and to the many microscopic air sacs where gases are exchanged </li></ul><ul><li>Respiration is the process of exchanging gases between the atmosphere and body cells </li></ul><ul><li>It consists of the following events: </li></ul><ul><ul><li>Ventilation </li></ul></ul><ul><ul><li>External respiration </li></ul></ul><ul><ul><li>Transport of gases </li></ul></ul><ul><ul><li>Internal respiration </li></ul></ul><ul><ul><li>Cellular respiration </li></ul></ul>
  3. 3. Section 19.2: Why We Breathe <ul><li>Respiration is necessary because of cellular respiration , the process by which animal cells use oxygen to release energy from nutrients we eat. The metabolic waste gas, carbon dioxide is produced during CR, and it must be transported to the lungs to be expelled . </li></ul><ul><li>Gas exchange, oxygen and carbon dioxide, occur at the cellular and molecular levels </li></ul><ul><li>Aerobic reactions of cellular respiration allow for: </li></ul><ul><ul><li>ATP production </li></ul></ul><ul><ul><li>Carbon dioxide generation forming carbonic acid </li></ul></ul>
  4. 4. Section 19.3: Organs of the Respiratory System <ul><li>The organs of the respiratory system can be divided into two tracts: </li></ul><ul><ul><li>Upper respiratory tract </li></ul></ul><ul><ul><ul><li>The nose </li></ul></ul></ul><ul><ul><ul><li>Nasal cavity </li></ul></ul></ul><ul><ul><ul><li>Sinuses </li></ul></ul></ul><ul><ul><ul><li>Pharynx </li></ul></ul></ul><ul><ul><li>Lower respiratory tract </li></ul></ul><ul><ul><ul><li>Larynx </li></ul></ul></ul><ul><ul><ul><li>Trachea </li></ul></ul></ul><ul><ul><ul><li>Bronchial tree </li></ul></ul></ul><ul><ul><ul><li>Lungs </li></ul></ul></ul>Larynx Bronchus Nostril Right lung Left lung Soft palate Pharynx Epiglottis Esophagus Frontal sinus Nasal cavity Hard palate Oral cavity Trachea
  5. 5. The Upper Respiratory Organs <ul><li>Lined with mucous membranes . </li></ul><ul><li>Epithelium over connective tissue with many goblet cells (mucus). </li></ul><ul><li>Specifically, pseudostratified columnar ET in the trachea. </li></ul><ul><li>The mucus functions to trap debris. </li></ul><ul><li>The cilia beat the debris to the pharynx to be swallowed and destroyed by digestive enzymes. </li></ul><ul><li>This tissue also serves to warm and moisten incoming air. </li></ul>
  6. 6. Nose Frontal sinus Nostril Hard palate Uvula Epiglottis Hyoid bone Larynx Superior Middle Inferior Sphenoidal sinus Pharyngeal tonsil Nasopharynx Palatine tonsil Oropharynx Lingual tonsil Laryngopharynx Esophagus Tongue Trachea Nasal conchae Opening of auditory tube <ul><li>Nose (external nares or nostrils) </li></ul><ul><li>bone and cartilage with internal hairs </li></ul><ul><li>traps large particles, filters </li></ul>
  7. 7. Nasal Cavity Mucus Particle Goblet cell Cilia Nasal cavity Epithelial cell (b) (a) <ul><li>Nasal cavity (separated by nasal septum) </li></ul><ul><li>bone and cartilage lined with mucous membranes </li></ul><ul><li>warms and moistens incoming air </li></ul><ul><li>olfactory reception </li></ul><ul><li>resonating chambers for speech </li></ul><ul><li>Nasal conchae (within nasal cavity) </li></ul><ul><li>superior, middle, and inferior </li></ul><ul><li>divide nasal cavity into a series of groove-like passageways </li></ul><ul><li>lined by mucous membranes </li></ul><ul><li>increase turbulence of incoming air (to better warm, moisten, and filter). </li></ul>
  8. 8. Boxed Reading: <ul><li>Nasal septum may bend during birth or shortly before adolescence </li></ul><ul><ul><li>Deviated septum </li></ul></ul><ul><ul><li>May obstruct nasal cavity </li></ul></ul><ul><ul><li>Breathing difficulties </li></ul></ul>
  9. 9. Sinuses <ul><li>Paranasal sinuses </li></ul><ul><li>within four skull bones (frontal, ethmoid, sphenoid, maxillary) </li></ul><ul><li>drain into nasal cavity </li></ul><ul><li>lined with mucous membranes </li></ul><ul><li>reduces weight of skull </li></ul><ul><li>resonating chambers for speech </li></ul>
  10. 10. Pharynx <ul><li>The pharynx is posterior to the oral cavity and between the nasal cavity and the larynx </li></ul>Frontal sinus Nostril Hard palate Uvula Epiglottis Hyoid bone Larynx Superior Middle Inferior Sphenoidal sinus Pharyngeal tonsil Nasopharynx Palatine tonsil Oropharynx Lingual tonsil Laryngopharynx Esophagus Tongue Trachea Nasal conchae Opening of auditory tube <ul><li>Pharynx (or throat) </li></ul><ul><li>wall of skeletal muscle lines with mucous membranes </li></ul><ul><li>passageway for air and food </li></ul><ul><li>resonant chamber for speech sounds </li></ul><ul><li>three parts: </li></ul><ul><ul><li>nasopharynx </li></ul></ul><ul><ul><li>oropharynx </li></ul></ul><ul><ul><li>laryngopharynx </li></ul></ul>
  11. 11. 19.1 Clinical Application <ul><li>The Effects of Cigarette Smoking </li></ul><ul><li>Slow, progressive & deadly </li></ul><ul><li>Cilia become paralyzed and then disappear </li></ul><ul><ul><li>Cannot remove debris </li></ul></ul><ul><li>Overproduction of mucus </li></ul><ul><li>More respiratory illnesses </li></ul><ul><li>Chronic bronchitis </li></ul><ul><li>Emphysema </li></ul><ul><li>Lung cancer </li></ul>
  12. 12. Larynx – Voice Box <ul><li>The larynx is an enlargement in the airway superior to the trachea and inferior to the pharynx </li></ul><ul><li>It is composed of a framework of muscles and cartilages bound by elastic tissue </li></ul>Epiglottic cartilage Hyoid bone Thyroid cartilage Cricoid cartilage Hyoid bone Epiglottic cartilage Thyroid cartilage Cricoid cartilage (b) (a) Trachea Trachea False vocal cord Glottis Epiglottis Hyoid bone Thyroid cartilage Cricoid cartilage Hyoid bone Epiglottis Thyroid cartilage Cricoid cartilage (b) (a) False vocal cord True vocal cord Thyroid cartilage Cuneiform cartilage Corniculate cartilage Arytenoid cartilage True vocal cord Glottis Corniculate cartilage (a) (b) Epiglottis Glottis (c) Posterior portion of tongue False vocal cord True vocal cord Cuneiform cartilage Inner lining of trachea c: © CNRI/PhotoTake
  13. 13. <ul><li>Anatomy (Nine pieces of cartilage) </li></ul><ul><li>1. thyroid cartilage (Adam's apple) </li></ul><ul><li>2. epiglottis closes off the airway during swallowing. </li></ul><ul><li>3 – 4.two pairs of vocal folds (false over true vocal cords) </li></ul><ul><li>5. Glottis = triangular slit opening between two pairs of vocal cords </li></ul><ul><li>6. Cricoid cartilage = ring of hyaline cartilage attached to first ring of trachea site of tracheotomy. </li></ul><ul><li>7. arytenoid cartilages </li></ul><ul><li>8. corniculate cartilages </li></ul><ul><li>9. cuneiform cartilages </li></ul>Larynx
  14. 14. <ul><li>Voice production </li></ul><ul><li>Mucous membranes form two pairs of folds. </li></ul><ul><ul><li>upper ventricular folds (false vocal cords) </li></ul></ul><ul><ul><li>lower vocal folds (true vocal cords) </li></ul></ul><ul><li>Triangular space between them = glottis. </li></ul><ul><li>Sound originates from vibration of the vocal folds, but other structures (pharynx, mouth, nasal cavity, and paranasal sinuses) convert that sound into recognizable speech. </li></ul>Larynx
  15. 15. Trachea <ul><li>Location = mediastinum anterior to esophagus extends from larynx to T5 </li></ul><ul><li>Structure: </li></ul><ul><li>6-20 incomplete rings of hyaline cartilage = C-rings </li></ul><ul><li>Rings are completed by trachealis muscle and elastic CT facing esophagus.. </li></ul><ul><li>lined by mucous membranes (pseudostratified columnar ET) </li></ul><ul><li>Carina = point where trachea divides into right & left primary bronchi. </li></ul><ul><li>Function = support against collapse continue to warm, moisten & filter air. </li></ul>Larynx Carina Trachea Superior (upper) lobe bronchus Right primary bronchus Middle lobe bronchus Inferior (lower) lobe bronchi Thyroid cartilage Cricoid cartilage Cartilaginous ring Left primary bronchus Superior (upper) lobe bronchus
  16. 16. Hyaline cartilage Ciliated epithelium Smooth muscle Lumen of trachea Connective tissue Connective tissue Hyaline cartilage Ciliated epithelium Lumen of trachea Smooth muscle Thyroid gland Incision Trachea Hyoid bone Thyroid cartilage Cricoid cartilage Jugular notch
  17. 17. Boxed Reading: <ul><li>December 13, 1799 </li></ul><ul><ul><li>George Washington has trouble breathing </li></ul></ul><ul><ul><li>How to fix this? </li></ul></ul><ul><ul><ul><li>Tracheostomy </li></ul></ul></ul><ul><ul><ul><li>Bleeding patient </li></ul></ul></ul><ul><ul><ul><li>Plastering throat with bran & honey </li></ul></ul></ul><ul><ul><ul><li>Beetles on legs to produce blisters </li></ul></ul></ul><ul><ul><li>Cause = epiglottitis </li></ul></ul><ul><ul><ul><li>Inflammation that swells epiglottis 10X </li></ul></ul></ul><ul><ul><ul><li>Tracheostomy might have saved his life! </li></ul></ul></ul>
  18. 18. Bronchial Tree <ul><li>primary bronchus leads into each lung and then branches into </li></ul><ul><li>secondary or lobar bronchi, which branch to each lobe and then branch into </li></ul><ul><li>tertiary or segmental bronchi which each serve one of 10 lobules (bronchopulmonary segment) that divide into </li></ul><ul><ul><li>intralobular bronchioles which branch several times into tubes called </li></ul></ul><ul><li>terminal bronchioles </li></ul>Larynx Right middle lobe Right superior (upper) lobe Right primary bronchus Secondary bronchus Right inferior (lower) lobe Alveolar duct Alveolus Respiratory bronchiole Tertiary bronchus Terminal bronchiole Trachea Left superior (upper) lobe Left inferior (lower) lobe
  19. 19. Branches of the Bronchial Tree <ul><li>The successive divisions of the branches from the trachea to the alveoli are: </li></ul><ul><li>Right and left primary bronchi </li></ul><ul><li>Secondary or lobar bronchi </li></ul><ul><li>Tertiary or segmental bronchi </li></ul><ul><li>Intralobular bronchioles </li></ul><ul><li>Terminal bronchioles </li></ul><ul><li>Respiratory bronchioles </li></ul><ul><li>Alveolar ducts </li></ul><ul><li>Alveolar sacs </li></ul><ul><li>Alveoli </li></ul>
  20. 20. Intralobular bronchiole Blood flow Alveolus Smooth muscle Alveoli Blood flow Blood flow Pulmonary artery Pulmonary vein Terminal bronchiole Respiratory bronchiole Pulmonary arteriole Pulmonary venule Capillary network on surface of alveolus Alveolar duct Alveolar sac Capillary Alveolus Simple squamous epithelial cells
  21. 21. The Respiratory Bronchioles <ul><li>The structure of the bronchus is similar to that of the trachea, but the C-shaped cartilaginous rings are replaced with cartilaginous plates where the bronchus enters the lung </li></ul><ul><li>These respiratory tubes become thinner and thinner, and the cell layers thin and change until the alveoli is reached </li></ul><ul><li>It is the alveoli that provides surface area for gas exchange </li></ul>Blood flow Blood flow Arteriole Alveolus Capillary Air O 2 CO 2 CO 2 Alveolar wall Venule O 2
  22. 22. Alveoli <ul><li>Walls consist of two types of epithelial cells and macrophages </li></ul><ul><ul><li>Type I Alveolar cells form a continuous simple squamous lining of the alveolar wall. </li></ul></ul><ul><ul><li>Type II Alveolar cells interrupt above lining and secrete surfactant : </li></ul></ul><ul><ul><ul><li>complex mixture = detergent </li></ul></ul></ul><ul><ul><ul><li>lowers surface tension and prevents alveolar collapse. </li></ul></ul></ul><ul><li>Alveolar Macrophages remove dust particles and other debris from alveolar spaces. </li></ul>
  23. 23. Boxed Reading: <ul><li>Cystic fibrosis </li></ul><ul><ul><li>Inherited disease </li></ul></ul><ul><ul><li>Causes clogged airways with thick, sticky mucus </li></ul></ul><ul><ul><ul><li>Attractive environment to bacteria </li></ul></ul></ul><ul><ul><ul><li>WBC’s DNA can clog area too </li></ul></ul></ul><ul><ul><li>Treatment = DNase </li></ul></ul><ul><ul><ul><li>Enzyme that degrades excess DNA </li></ul></ul></ul>
  24. 24. Blood vessel Capillary Alveolus Bronchiole Alveolus
  25. 25. <ul><li>Techniques to save a life when a person stops breathing: </li></ul><ul><li>Artificial respiration </li></ul><ul><ul><li>CPR </li></ul></ul><ul><li>Extracorporeal membrane oxygenation </li></ul><ul><ul><li>Blood out of body, through gas-permeable membrane to add oxygen and remove carbon dioxide, blood pumped back into body </li></ul></ul><ul><li>Intravascular oxygenator </li></ul><ul><ul><li>Lung assist device </li></ul></ul><ul><ul><li>Hundreds of porous hair-thin fibers implanted into inferior vena cava, receives oxygen here and gets rid of carbon dioxide </li></ul></ul><ul><ul><li>Only 30% efficacy of normal respiratory system </li></ul></ul>Boxed Reading:
  26. 26. Lungs <ul><li>Location = thoracic cavity </li></ul><ul><li>Description: </li></ul><ul><li>paired, cone-shape organs </li></ul><ul><li>covered by pleural (serous) membranes </li></ul><ul><ul><li>visceral pleura </li></ul></ul><ul><ul><li>parietal pleura </li></ul></ul><ul><ul><li>pleural cavity filled with serous fluid with high surface tension so membranes act as one </li></ul></ul>Thyroid cartilage Cricoid cartilage Clavicle Scapula Rib cartilage Sternum Superior (upper) lobe of right lung Middle lobe of right lung Inferior (lower) lobe of right lung Superior (upper) lobe of left lung Inferior (lower) lobe of left lung Trachea Right lung Heart Left lung Pericardium Pleura Plane of section Pericardial cavity Right pleural cavity Visceral pleura Parietal pleura Left pleural cavity
  27. 27. Lungs <ul><li>Gross Anatomy: </li></ul><ul><ul><ul><ul><ul><li>Each lung is divided into lobes by fissures: </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Right lung has 3 lobes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Left lung has 2 lobes. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Each lobe : </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>receives a secondary bronchus </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>is divided into lobules (bronchopulmonary segment) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Each lobule : </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>is wrapped in elastic CT </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>contains a lymphatic vessel, an arteriole, a venule, and a branch from a terminal bronchiole </li></ul></ul></ul></ul></ul>
  28. 28. Review:
  29. 29. 19.2 Clinical Application <ul><li>Lung Irritants </li></ul><ul><li>Asbestos </li></ul><ul><ul><li>Asbestosis = shortness of breath due to lung scar tissue </li></ul></ul><ul><ul><li>Lung cancer </li></ul></ul><ul><li>Berylliosis </li></ul><ul><ul><li>Beryllium used in metal alloys & nuclear power </li></ul></ul><ul><ul><li>Symptoms appear 10 years after exposure </li></ul></ul><ul><ul><ul><li>Cough, shortness of breath, fatigue, loss of appetite, fever, night sweats, weigh loss </li></ul></ul></ul><ul><li>A disorder with many names </li></ul><ul><ul><li>Extrinsic allergic alveolitis </li></ul></ul><ul><li>9/11 associated air pollution </li></ul><ul><ul><li>World trade center cough </li></ul></ul><ul><ul><li>Particles of fiberglass, asbestos, concrete, etc </li></ul></ul>
  30. 30. Section 19.4: Breathing Mechanism <ul><li>Breathing or ventilation is the movement of air from outside of the body into the bronchial tree and the alveoli </li></ul><ul><li>The actions responsible for these air movements are inspiration, or inhalation, and expiration, or exhalation </li></ul>
  31. 31. Atmospheric Pressure <ul><li>Atmospheric pressure due to the weight of the air is the force that moves air into the lungs </li></ul><ul><li>At sea level, atmospheric pressure is 760 millimeters of mercury (mm Hg) </li></ul><ul><li>Moving the plunger of a syringe causes air to move in or out </li></ul><ul><li>Air movements in and out of the lungs occur in much the same way </li></ul>Diaphragm Air passageway Atmospheric pressure of 760 mm Hg on the outside Atmospheric pressure of 760 mm Hg on the inside (a) (b)
  32. 32. Inspiration <ul><li>The diaphragm muscle pushes downward. </li></ul><ul><li>The size of thoracic cavity increases. </li></ul><ul><li>The pressure in the thoracic cavity decreases (758 mm Hg) </li></ul><ul><li>The air pressure inside the thoracic cavity (lungs) is less than the atmospheric pressure and therefore air rushes into lungs to equalize the pressure gradient. </li></ul>Diaphragm (a) (b) Intra-alveolar pressure (760 mm Hg) Atmospheric pressure (760 mm Hg) Intra-alveolar pressure (758 mm Hg)
  33. 33. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (a) (b) External intercostal muscles pull ribs up and out Diaphragm contracts Sternum moves Up and out Sternocleidomastoid elevates sternum Pectoralis minor elevates ribs Diaphragm contracts more Inspiration
  34. 34.
  35. 35. Expiration <ul><li>The forces responsible for normal resting expiration come from elastic recoil of lung tissues and from surface tension </li></ul><ul><li>These factors increase the intra-alveolar pressure about 1 mm Hg above atmospheric pressure forcing air out of the lungs </li></ul>
  36. 36. Expiration Diaphragm Diaphragm (a) (b) Abdominal organs recoil and press diaphragm upward Posterior internal intercostal muscles pull ribs down and inward Abdominal organs force diaphragm higher Abdominal wall muscles contract and compress abdominal organs
  37. 37.
  38. 39. Lung Problems: <ul><li>Atelectasis (Collapsed Lung) </li></ul><ul><ul><li>At the end of an expiration, the alveoli tend to recoil inward and collapse on themselves. </li></ul></ul><ul><ul><li>Surfactant (mixture of phospholipid & proteins) produced by Type II Alveolar cells decreases the surface tension in the lungs. </li></ul></ul><ul><ul><li>As the alveoli become smaller during expiration, the surfactant overcomes the pressure differential and allows the alveoli to remain inflated. </li></ul></ul><ul><li>Respiratory Distress Syndrome (RDS) in premature newborns (collapsed lungs) occurs due to the lack of surfactant in the alveoli. </li></ul>
  39. 40. Boxed Reading: <ul><li>Premature infants often do not have enough surfactant which can result in respiratory distress syndrome </li></ul><ul><ul><li>Synthetic surfactant injection & ventilators </li></ul></ul><ul><li>Pneumothorax </li></ul><ul><ul><li>Space between visceral & parietal membranes of lung </li></ul></ul><ul><ul><li>Collapses lung due to lack of elasticity </li></ul></ul><ul><ul><li>Treatment = cover chest wound, pass chest tube through thoracic wall into pleural cavity, apply suction </li></ul></ul><ul><ul><ul><li>Suction reestablishes negative pressure in cavity & lung expands </li></ul></ul></ul>
  40. 41. Respiratory Air Volumes and Capacities <ul><li>Different degrees of effort in breathing move different volumes of air in and out of the lungs </li></ul><ul><li>This measurement of volumes is called spirometry </li></ul>Lung volume in milliliters (mL) 6,000 5,000 4,000 3,000 2,000 1,000 0 Inspiratory reserve volume Tidal volume Residual volume Expiratory reserve volume Vital capacity Inspiratory capacity Total lung capacity Functional residual capacity
  41. 42. Know this table!
  42. 43. Alveolar Ventilation <ul><li>The volume of new atmospheric air moved into the respiratory passages each minute is minute ventilation </li></ul><ul><li>It equals the tidal volume multiplied by the breathing rate </li></ul><ul><ul><li>About 6000mL </li></ul></ul><ul><li>Much of the new air remains in the physiologic dead space </li></ul><ul><ul><li>approximately 150mL </li></ul></ul><ul><li>The tidal volume minus the physiologic dead space then multiplied by breathing rate is the alveolar ventilation rate </li></ul><ul><ul><li>AV = (TV – ADS) X RR </li></ul></ul><ul><li>This is the volume of air that reaches the alveoli </li></ul><ul><li>This impacts the concentrations of oxygen and carbon dioxide in the alveoli </li></ul>
  43. 44. Non-respiratory Air Movements <ul><li>Air movements other than breathing are called nonrespiratory movements </li></ul><ul><li>Cough = sends blast of air through and clears lower respiratory tract </li></ul><ul><li>Sneeze = forcefully expels air through nose & mouth </li></ul><ul><li>Laugh = a deep breath released in a series of short convulsive expirations </li></ul><ul><li>Hiccup = spasmodic contraction of diaphragm </li></ul><ul><li>Yawn = deep inspiration through open mouth (ventilates alveoli). </li></ul>
  44. 45. Boxed Reading: <ul><li>Sensitive areas of air passages = larynx, carina, and near major bronchi branches </li></ul><ul><li>Areas lacking nerve supply = respiratory bronchioles, alveolar ducts, and alveoli </li></ul><ul><ul><li>Debris must move to larger passage to trigger a cough reflex </li></ul></ul>
  45. 46.
  46. 47. 19.3 Clinical Application <ul><li>Respiratory Disorders That Decrease Ventilation: </li></ul><ul><li>Bronchial Asthma </li></ul><ul><ul><li>Allergic reaction to foreign antigens </li></ul></ul><ul><ul><li>Mucus drainage in lower respiratory tract </li></ul></ul><ul><ul><li>Edematous secretions irritate smooth muscles stimulating bronchoconstriction </li></ul></ul><ul><ul><li>Breathing difficulties & wheezing </li></ul></ul><ul><ul><li>Harder to breath out than in </li></ul></ul><ul><li>Emphysema </li></ul><ul><ul><li>Progressive, degenerative disease that destroys alveolar walls </li></ul></ul><ul><ul><li>Difficult to force air out due to loss of tissue elasticity </li></ul></ul><ul><ul><li>Experimental treatment = lung volume reduction surgery </li></ul></ul>
  47. 48. Section 19.5: Control of Breathing <ul><li>Normal breathing is a rhythmic, involuntary act that continues when a person is unconscious </li></ul><ul><li>Respiratory muscles can be controlled as well voluntarily </li></ul>
  48. 49. Respiratory Areas <ul><li>Groups of neurons in the brainstem comprise the respiratory areas that control breathing </li></ul><ul><li>Impulses travel on cranial nerves and spinal nerves, causing inspiration and expiration </li></ul><ul><li>Respiratory areas also adjust the rate and depth of breathing </li></ul><ul><li>The respiratory areas include: </li></ul><ul><ul><li>Respiratory center of the medulla </li></ul></ul><ul><ul><li>Respiratory group of the pons </li></ul></ul>Diaphragm Medulla oblongata Pons Midbrain Dorsal respiratory group Pontine respiratory group Ventral respiratory group Fourth ventricle Medullary respiratory center Internal (expiratory) intercostal muscles External (inspiratory) intercostal muscles
  49. 50. Respiratory muscles Forceful breathing Nerve impulses Nerve impulses Pontine respiratory group Ventral respiratory group Dorsal respiratory group Medullary respiratory center Respiratory areas Basic rhythm of breathing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  50. 51. Factors Affecting Breathing <ul><li>A number of factors affect breathing rate and depth including: </li></ul><ul><ul><li>Partial pressure of oxygen (Po 2 ) </li></ul></ul><ul><ul><li>Partial pressure of carbon dioxide (Pco 2 ) </li></ul></ul><ul><ul><li>Degree of stretch of lung tissue </li></ul></ul><ul><ul><li>Emotional state </li></ul></ul><ul><ul><li>Level of physical activity </li></ul></ul><ul><li>Receptors involved include mechanoreceptors and central and peripheral chemoreceptors </li></ul>Carotid bodies Aorta Heart Aortic bodies Medulla oblongata Sensory nerve (branch of glossopharyngeal nerve) Common carotid artery Sensory nerve (branch of vagus nerve )
  51. 52. Boxed Reading: <ul><li>Sleep apnea – cause of SID & snoring </li></ul><ul><li>Infants – problem with respiratory control centers </li></ul><ul><ul><li>Sleeping on back or side is safest </li></ul></ul><ul><li>Adults – obstructive apnea </li></ul><ul><ul><li>Breathing ceased for 10 to 20 sec, 100X night </li></ul></ul><ul><ul><li>Results in fatigue, headache, depression, & drowsiness </li></ul></ul><ul><ul><li>Diagnosed in sleep lab </li></ul></ul><ul><ul><li>Treatment = nasal continuous positive airway pressure </li></ul></ul><ul><ul><ul><li>Device that maintains airflow to respiratory system </li></ul></ul></ul>
  52. 54. Factors Affecting Breathing <ul><li>Changes in blood pH, O 2 and CO 2 concentration stimulates chemoreceptors </li></ul><ul><li>Motor impulses can travel from the respiratory center to the diaphragm and external intercostal muscles </li></ul><ul><li>Contraction of these muscles causes the lungs to expand stimulating mechanoreceptors in the lungs </li></ul><ul><li>Inhibitory impulses from the mechanoreceptors back to the respiratory center prevent over inflation of the lungs </li></ul>Respiratory center Motor pathways Spinal cord Intercostal nerve Rib Diaphragm Sensory pathway Phrenic nerve Stretch receptors Lung External intercostal muscles Vagus nerve – –
  53. 55. <ul><li>Adding CO 2 to air will stimulate rate and depth of breathing </li></ul><ul><li>Patients with COPD gradually adapt to high concentrations of CO 2 </li></ul><ul><ul><li>Therefore lower O 2 levels stimulate breathing </li></ul></ul>
  54. 56. Boxed Reading: <ul><li>Hyperventilation </li></ul><ul><li>Caused by emotional upset </li></ul><ul><li>Lowered CO 2 levels & rise in pH </li></ul><ul><ul><li>Respiratory alkalosis </li></ul></ul><ul><li>Localized vasoconstriction of cerebral arterioles </li></ul><ul><ul><li>Decrease blood supply to brain </li></ul></ul><ul><ul><li>Can cause fainting </li></ul></ul>
  55. 57. 19.4 Clinical Application <ul><li>Exercise and Breathing </li></ul><ul><li>Exercise increases breathing rate </li></ul><ul><ul><li>Muscles need more O 2 but also produce more CO 2 </li></ul></ul><ul><ul><li>P O and P CO 2 rates don’t change </li></ul></ul><ul><li>Increase demand on respiratory & cardiovascular systems </li></ul><ul><ul><li>“ out of breath” feeling = inability of cardiovascular system to move enough blood between lungs and cells </li></ul></ul>
  56. 58. Section 19.6: Alveolar Gas Exchanges <ul><li>The alveoli are the sites of the vital process of gas exchange between the air and the blood </li></ul><ul><ul><li>Air is a mixture of gases: </li></ul></ul><ul><ul><ul><li>78% Nitrogen </li></ul></ul></ul><ul><ul><ul><li>21% Oxygen </li></ul></ul></ul><ul><ul><ul><li>.04% Carbon Dioxide </li></ul></ul></ul><ul><ul><li>In a mixture of gases, the amount of pressure that each gas creates = partial pressure. </li></ul></ul><ul><ul><li>In air that reaches the alveoli: </li></ul></ul><ul><ul><ul><li>O2 = 21% PO2 = 104 mm Hg </li></ul></ul></ul><ul><ul><ul><li>CO2 = .04% PCO2 = 40 mm Hg </li></ul></ul></ul>
  57. 59. Alveoli
  58. 61. <ul><ul><li>Diffusion of gases through the respiratory membrane proceeds from where a gas is at high pp  low pp. </li></ul></ul><ul><li> Alveolus </li></ul><ul><li>PCO2 = 40 mm Hg PO2 = 104 mm Hg </li></ul><ul><li>↑ ↓ </li></ul><ul><li>_________________________________________________ </li></ul><ul><li>PCO2 = 45 mm Hg PO2 = 40 mm Hg </li></ul><ul><li> Capillary </li></ul><ul><li>Therefore, CO2 will flow from lung capillary to the alveolus & O2 will flow from alveolus to the lung capillary. </li></ul>
  59. 62. Capillary lumen Alveolus Macrophage Capillary Alveolus Red blood cell Diffusion of CO 2 Diffusion of O 2 Capillary endothelium Interstitial space Alveolar epithelium Type I (squamous epithelial) cell of alveolar wall Type II (surfactant- secreting) cell Fluid with surfactant Respiratory membrane Cell of capillary wall Alveolar fluid (with surfactant) Basement membrane of alveolar epithelium Basement membrane of capillary endothelium Respiratory membrane
  60. 63. Respiratory Membrane <ul><li>Part of the wall of an alveolus is made up of cells (type II cells) that secrete pulmonary surfactant </li></ul><ul><li>The bulk of the wall of an alveolus consists of a layer of simple squamous epithelium (type I cells) </li></ul><ul><li>Both of these layers make up the respiratory membrane through which gas exchange takes place </li></ul>
  61. 64. AS AS BM IS RBC EP
  62. 65. Alveolus Diffusion of CO 2 Diffusion of O 2 Capillary Alveolar wall Blood flow (from body tissues) Blood flow (to body tissues) P CO 2 = 45 mm Hg P CO 2 = 40 mm Hg P O 2 = 40 mm Hg P O 2 = 104 mm Hg P O 2 = 104 mm Hg P CO 2 = 40 mm Hg
  63. 66. Diffusion Through the Respiratory Membrane <ul><ul><li>The rate of diffusion of gases also depends on a number of factors, including the following: </li></ul></ul><ul><ul><ul><li>gas exchange surface area </li></ul></ul></ul><ul><ul><ul><li>diffusion distance </li></ul></ul></ul><ul><ul><ul><li>breathing rate and depth. </li></ul></ul></ul><ul><ul><li>Increased diffusion is favored with more surface area, shorter distance, greater solubility of gases and a steeper partial pressure gradient </li></ul></ul><ul><ul><li>Decreased diffusion occurs from decreased surface area </li></ul></ul>
  64. 67. Boxed Reading: <ul><li>Hyperoxia </li></ul><ul><ul><li>Exposure to high oxygen concentration </li></ul></ul><ul><ul><li>May damage lung tissue (esp. capillary wall) </li></ul></ul><ul><ul><li>Excess fluid escapes capillaries and flood alveolar air spaces </li></ul></ul><ul><ul><ul><li>Interfers with gas exchange </li></ul></ul></ul><ul><ul><li>Retrolental fibroplasia (RLF) </li></ul></ul><ul><ul><ul><li>Infants with damaged retinal capillaries </li></ul></ul></ul><ul><ul><ul><li>Can lead to blindness </li></ul></ul></ul>
  65. 68. Section 19.7: Gas Transport <ul><li>Blood transports O 2 and CO 2 between the lungs and the body cells </li></ul><ul><li>As the gases enter the blood, they dissolve in the plasma or chemically combine with other atoms or molecules </li></ul>
  66. 70. Oxygen Transport <ul><li>Almost all oxygen carried in the blood is bound to the protein hemoglobin in the form of oxyhemoglobin </li></ul><ul><li>Chemical bonds between O 2 and hemoglobin are relatively unstable </li></ul><ul><li>Oxyhemoglobin releases O 2 into the body cells </li></ul><ul><li>About 75% of the O 2 remains bound to hemoglobin in the venous blood ensuring safe CO 2 levels and thereby pH </li></ul>
  67. 71. Alveolus Capillary 2 2 2 (a) (b) Blood flow (from body tissues) Alveolar wall Oxygen molecules Hemoglobin molecules Diffusion of oxygen Oxyhemoglobin molecule Hemoglobin molecules Diffusion of oxygen Blood flow (to lungs) Blood P O = 40 mm Hg Blood P O = 95 mm Hg Tissue cells Tissue P O = 40 mm Hg
  68. 72. 10 20 30 40 50 60 70 80 90 100 Oxyhemoglobin dissociation at 38°C % saturation of hemoglobin 10 0 40 50 60 70 90 80 100 1 10 120 130 140 20 30 P O 2 (mm Hg)
  69. 73. <ul><ul><ul><li>The release of oxygen from hemoglobin depends on many factors : </li></ul></ul></ul><ul><ul><ul><li>high blood [CO2] </li></ul></ul></ul><ul><ul><ul><li>low blood pH (acidity) </li></ul></ul></ul><ul><ul><ul><li>high blood temperature </li></ul></ul></ul><ul><ul><ul><li>Carbon Monoxide (CO) binds to hemoglobin more efficiently than oxygen. </li></ul></ul></ul><ul><ul><ul><li>If the hemoglobin (that is supposed to bind with oxygen) is bound to CO, much less Hb is available to bind and transport oxygen to the tissues </li></ul></ul></ul><ul><ul><ul><li>Hypoxia results. </li></ul></ul></ul>
  70. 74. 19.5 Clinical Application <ul><li>Effects of High Altitude </li></ul><ul><li>High-altitude pulmonary edema (HAPE) </li></ul><ul><li>Severe attitude sickness with headache, nausea, vomiting, rapid heart rate and breathing, & cyanotic skin </li></ul><ul><li>Hypoxia causes vasoconstriction of pulmonary blood vessels </li></ul>
  71. 75. <ul><li>The amount of oxygen released from oxyhemoglobin increases with: </li></ul>10 20 30 40 50 60 70 80 90 100 % saturation of hemoglobin 10 0 40 50 60 70 90 80 100 1 10 120 130 140 20 30 Oxyhemoglobin dissociation at 38°C 20 mm Hg 40 mm Hg 80 mm Hg P CO 2 = P O 2 (mm Hg) 10 20 30 40 50 60 70 80 90 100 Oxyhemoglobin dissociation at 38°C % saturation of hemoglobin 10 0 40 50 60 70 90 80 100 1 10 120 130 140 20 30 7.6 7.4 7.2 pH = P O 2 (mm Hg) 10 20 30 40 50 60 70 80 90 100 % saturation of hemoglobin 10 0 40 50 60 70 90 80 100 1 10 120 130 140 20 30 43°C 38°C 30°C 20°C 10°C 0°C P O 2 (mm Hg) Oxyhemoglobin dissociation at various temperatures Increased in P CO 2 Increased blood pH Increased blood temperature
  72. 76. 19.6 Clinical Application <ul><li>Disorders That Impair Gas Exchange: </li></ul><ul><li>Pneumonia </li></ul><ul><ul><li>Bacterial infection </li></ul></ul><ul><ul><li>Edema in alveoli causing reduced diffusion </li></ul></ul><ul><li>Tuberculosis </li></ul><ul><ul><li>Bacterial infection </li></ul></ul><ul><ul><li>Fibrous tubercles form causing reduced diffusion </li></ul></ul><ul><li>Adult Respiratory Distress Syndrome </li></ul><ul><ul><li>Caused by: pneumonia, near drowning, shock, sepsis, physical trauma, etc. </li></ul></ul><ul><ul><li>Results in collapsed lungs </li></ul></ul>
  73. 77. Carbon Dioxide Transport <ul><li>Blood flowing through capillaries gains CO 2 because the tissues have a high Pco 2 </li></ul><ul><li>The CO 2 is transported to the lungs in one of three forms: </li></ul><ul><ul><li>As CO 2 dissolved in plasma </li></ul></ul><ul><ul><li>As part of a compound with hemoglobin </li></ul></ul><ul><ul><li>As part of a bicarbonate ion </li></ul></ul>
  74. 78. Tissue cell Cellular CO 2 Plasma Red blood cell Capillary wall Blood flow to systemic venule Tissue P CO 2 = 45 mm Hg CO 2 dissolved in plasma P CO 2 = 40 mm Hg Blood flow from systemic arteriole CO 2 combined with hemoglobin to form carbaminohemoglobin H 2 CO 3 H + combines with hemoglobin P CO 2 = 45 mm Hg HCO 3 - + H + CO 2 + H 2 O HCO 3 -
  75. 79. HCO 3 - Red blood cell HCO 3 - Cl - Cl - Cl - HCO 3 - Plasma Capillary wall
  76. 80. CO 2 CO 2 Alveolus Alveolar wall Capillary wall CO 2 HCO 3 - Carbaminohemoglobin Plasma Red blood cell P CO 2 = 45 mm Hg P CO 2 = 40 mm Hg CO 2 CO 2 dissolved in plasma Blood flow from pulmonary arteriole HCO 3 - + H + H 2 CO 3 H + released from hemoglobin Blood flow to pulmonary venule P CO 2 = 40 mm Hg + H 2 O CO 2 + hemoglobin
  77. 81.
  78. 82. Section 19.8: Lifespan Changes <ul><li>Lifespan changes reflect an accumulation of environmental influences and the effects of aging in other organ systems, and may include: </li></ul><ul><ul><li>The cilia become less active </li></ul></ul><ul><ul><li>Mucous thickening </li></ul></ul><ul><ul><li>Swallowing, gagging, and coughing reflexes slowing </li></ul></ul><ul><ul><li>Macrophages in the lungs lose efficiency </li></ul></ul><ul><ul><li>An increased susceptibility to respiratory infections </li></ul></ul><ul><ul><li>A “barrel chest” may develop </li></ul></ul><ul><ul><li>Bronchial walls thin and collapse </li></ul></ul><ul><ul><li>Dead space increasing </li></ul></ul>
  79. 83. Important Points in Chapter 19: <ul><li>19.1: Introduction </li></ul><ul><li>Identify the general functions of the respiratory system. </li></ul><ul><li>19.2: Why We Breathe </li></ul><ul><li>Explain why respiration is necessary for cellular survival. </li></ul><ul><li>19.3: Organs of the Respiratory System </li></ul><ul><li>Name and describe the locations of the organs of the respiratory system. </li></ul><ul><li>Describe the functions of each organ of the respiratory system. </li></ul><ul><li>19.4: Breathing Mechanism </li></ul><ul><li>Explain how inspiration and expiration are accomplished. </li></ul><ul><li>Name and define each of the respiratory air volumes and capacities. </li></ul>
  80. 84. Important Points in Chapter 19: <ul><li>Calculate the alveolar ventilation rate. </li></ul><ul><li>List several non-respiratory air movements and explain how each occurs. </li></ul><ul><li>19.5: Control of Breathing </li></ul><ul><li>Locate the respiratory areas and explain control of normal breathing. </li></ul><ul><li>Discuss how various factors affect breathing. </li></ul><ul><li>19.6: Alveolar Gas Exchanges </li></ul><ul><li>Define partial pressure and explain its importance in diffusion of gases. </li></ul><ul><li>Describe gas exchange in the pulmonary and systemic circuits. </li></ul>
  81. 85. Important Points in Chapter 19: <ul><li>Describe the structure and function of the respiratory membrane. </li></ul><ul><li>19.7: Gas Transport </li></ul><ul><li>Explain how the blood transports oxygen and carbon dioxide. </li></ul><ul><li>19.8: Lifespan Changes </li></ul><ul><li>Describe the effects of aging on the respiratory system. </li></ul>