PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Tenth Edition Shier w Butler w Lewis Chapter 19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19-1 Chapter 19 Respiratory System Respiration is the process of exchanging gases between the atmosphere and body cells. Consists of the following events: • ventilation- air in and out of lungs • external respiration- air and blood in lungs • transport • internal respiration- blood and tissue • cellular respiration-oxygen and co2 19-2 Structures • Nose –nares • Nasal cavity- separated from cranial and oral cavity- ethmoid and maxilla • Nasal septum- ethmoid and vomer • Meatus- superior, middle, and inferior • Pharynx- smell, conducts air, entraps particles, moistens, and heats air • Cilia- moves mucus and particles toward pharynx • • • • • • • • Larynx- vocal cord, epiglottis, and cartilages Trachea- cartilage, muscle, and elastic Bronchial tree- RT. And LT. main stem bronchi Secondary- lobar – three on right and two on left Tertiary- ten on the right and eight on the left Interlobular- lobules Terminal- 50 to 80 within each lobule of lung Respiratory- 2 or 3 branch from each terminal – Alveolar ducts----branch into sacs----Alveoli Organs of the Respiratory System 19-3 Upper Respiratory Tract 19-4 Mucous in Respiratory Tract Cilia move mucus and trapped particles from the nasal cavity to the pharynx Trachea- bronchi-bronchioles-Ciliated Pseudocolumnar epithelium Goblet cells secrete mucus 19-5 Sinuses Air-filled spaces in maxillary, frontal, ethmoid, and sphenoid bones Functions are to reduce the weight of the scull and serve as resonant chambers that affect the quality of the voice. 19-6 Larynx 19-7 • • • • Upper lateral folds- false vocal cords True vocal cords- responsible for sound Laryngeal muscles- control pitch Glottis and epiglottis- close during swallowing Tracheostomy Performed to allow air to bypass an obstruction within the larynx 19-8 Cartilage • Larynx superior to the trachea and inferior to the pharynx. • Composed of muscles and cartilage • Cartilage- thyroid, cricoid, and epiglottic • Thyroid- superior to the thyroid gland • Cricoid -inferior to the thyroid gland • Epiglottic- attached to the upper border of the thyroid cartilage Trachea • Anterior to the esophagus- located in the thoracic cavity (Mediastinum) • Trachea and bronchi supported with Cshaped hyaline cartilage. • Posteriorly- incomplete rings contain muscle and connective tissue • Carina-projection of the last trachea ring, located in the sagittal plane.( associated with the cough reflex) • Spits into Right and left main stem bronchus 19-10 Trachea and Bronchi • Right main bronchus is wider, shorter and runs more vertically than the left. • Left main bronchus passes inferiorly to the arch of the aorta and anterior to the esophagus. • Lobar bronchi- secondary branches –two on the left and three on the right. • Tertiary bronchi-several segments that branch into 20-25 terminal bronchioles. • Respiratory bronchioles- contain 11-alveolar ducts and 5-6 alveolar sacs. Fully developed by age 8, with 300 million alveoli 14 Trachea Cross section of trachea Wall of trachea 19-12 Bronchial Tree 19-13 Alveoli 19-14 Location of Lungs 19-15 Muscles of the Thoracic Wall • Pectoral muscles- major and minor • Subclavius • Serratus anterior- rotates the scapula and holds the scapula against the thoracic wall. • Scalene muscles- from the neck to the 1st and 2 nd ribs, elevate ribs during forced inspiration • Intercostal muscles- between ribs • External intercostal muscles- muscles of inspirationelevate the ribs. • Internal intercostals- are muscles of expiration. • Innermost intercostals- deep, separated from internal intercostals by nerves and vessels. • Subcostal muscles- aid in elevation of ribs 19 Transverse Section of Lungs 19-17 CO2-transportation • Co2 is stored in three forms: – 6%- is dissolved in solution – 8%- is bound to hemoglobin-Carbaminohemoglobin – 90%-is dissolved in blood as bicarbonate – CO2+H2O H2CO3HCO3 +H – Chloride Shift-Tissue and Blood Co2 diffuses inside a RBC forming carbonic acid. Carbonic acid rapidly dissociates into hydrogen and bicarbonate ions. Hydrogen binds to deoxyhemoglobin and HCO3ˉ diffuses out of the RBC. Chloride, which is also negatively charged, enters the RBC. Chloride Shift • bicarbonate ions diffuse out RBCs • chloride ions from plasma diffuse into RBCs • electrical balance is maintained 19-38 Carbon Dioxide Transport • dissolved in plasma • combined with hemoglobin • in the form of bicarbonate ions 19-37 • Reverse-capillaries of the lungs • Deoxyhemoglobin----Oxyhemoglobin Hydrogen is released, combines with bicarbonate, forming carbonic acid. H+ + HCO3ˉ---H2CO3----CO2 + H2O CO2-expired Carbon Dioxide in Lungs 19-39 Diffusion Through Respiratory Membrane Gases are exchanged between alveolar air and capillary blood because of differences in partial pressure 19-34 Oxygen Transport • Most oxygen binds to hemoglobin to form oxyhemoglobin • Oxyhemoglobin releases oxygen in the regions of body cells • Much oxygen is still bound to hemoglobin in the venous blood 19-35 Review Questions • Most of the carbon dioxide is present in the blood as bicarbonate. • The conversion of CO2 to bicarbonate occurs primarily within the erythrocytes. • In the lung, the reaction is determined by carbon dioxide relative to bicarbonate ion concentration. • Chloride is transported into the RBC at the same time bicarbonate moves out. The H released from carbonic acid binds to hemoglobin. The increase in the affinity of hemoglobin for CO2 corresponds to a lowered O2. TERMS • Two Types of alveolar cells – Type I- 95%-gas exchange – Type II- Secrete surfactant and reabsorb Na and water PressuresAtmospheric pressure at sea level 760mmHg or 760 torr Dalton’s Law, the total pressure of a gas mixture is equal to the sum of the pressures that each gas in the mixture would exert independently. Partial pressure of a particular gas- is equal to the product of the total pressure and the fraction of that gas in the mixture. Normal Breathing • Breathing rhythm involves the medulla and the pons. – Inspiratory and expiratory neurons – Inspiration- action potential travels via the phrenic nerves motor neurons are activated and contraction of diaphragm and external intercostals occurs. As the stimuli increases other respiratory muscles contract, increasing the volume of the lung. Quiet breathing means passive relaxation of the muscles. Then the next breathing cycle is initiated. • Oxygen- 21% of the atmosphere-.21 (760 -47) = 150mmHg • Henry’s law-Since solubility is a constant and the temperature of blood does not vary, the concentration of a gas dissolved in a fluid depends directly on its partial pressure in the gas mixture. Blood gases are measured using an oxygen electrode Expiration- Passive • The elastic recoil of the lung reduces pressure in the cavity, therefore increasing the intra alveolar pressure above atmospheric pressure. Air inside the lungs is forced out. • During exhalation the diaphragm moves upward and the ribs move downward. • Forced expiration- involves contraction of the internal intercostal and abdominal muscles. Lungs at Rest When lungs are at rest, the pressure on the inside of the lungs is equal to the pressure on the outside of the thorax 19-16 Air Movements • Moving the plunger of a syringe causes air to move in or out • Air movements in and out of the lungs occur in much the same way 19-17 Inspiration • Intra-alveolar pressure decreases to about 758mm Hg as the thoracic cavity enlarges • Atmospheric pressure forces air into the airways 19-18 Maximal Inspiration Thorax at end of normal inspiration Thorax at end of maximal inspiration • aided by contraction of sternocleidomastoid and pectoralis minor muscles 19-19 Expiration • due to elastic recoil of the lung tissues and abdominal organs 19-20 Maximal Expiration • contraction of abdominal wall muscles • contraction of posterior internal intercostal muscles 19-21 Respiratory Volumes •TV- tidal volume – volume moved in or out during a normal breath •IRV- inspiratory reserve volume – volume that can be inhaled during forced breathing in addition to tidal volume • ERV-expiratory reserve volume – volume that can be exhaled during forced breathing in addition to tidal volume • RV-residual volume – volume that remains in lungs at all times • FRV-functional residual capacity = ERV + RV • IC-inspiratory capacity = TV + IRV • VC-vital capacity = TV + IRV + ERV • TLC-total lung capacity = VC + RV 19-22 • Imagine a TV set in a house the width of the house represents the difference in the volume of the lung between maximum inspiration and maximum expiration. On either side of the TV are Irvine and Erving. The get tired of the TV, so they go outside to use their RV. The weather is cold and icy, and they get into an accident, leading them to crash into their own house, whereupon they mutter “This frickin’ice”(FRC,IC). They are admitted to the hospital where they have their vital signs taken. They recover with TLC. 19-23 Respiratory Volumes and Capacities 19-24 Alveolar Ventilation minute ventilation • tidal volume multiplied by breathing rate • amount of air that is moved into the respiratory passageways alveolar ventilation rate • major factor affecting concentrations of oxygen and carbon dioxide in the alveoli • volume of air that reaches alveoli • tidal volume minus physiologic dead space then multiplied by breathing rate 19-25 Factors that influence the rate of respiration • Pons and medulla regulate breathing • CO2 levels establishes the rate of breathing • Mechanoreceptor reflexes respond to changes in the volume of the lungs and arterial blood pressure. • An elevated body temperature will increase respiration • Chemoreceptor respond to changes in the oxygen and carbon dioxide of the blood and CSF. (eg. Decrease O2 : increase ventilation) – Carotid and aortic arch- Review Questions • Pneumotaxic center- stimulatory effect on respiration • An increase in CO2 will increase the concentration of H+ in the RBC, which will decrease the pH of the blood. • A 10% increase in arterial CO2- will increase the rate of breathing • Carbon dioxide- most is transported as bicarbonate ions • Oxygen is transported by hemoglobin Respiratory Center 19-27 Respiratory Center 19-28 Factors Affecting Breathing Decreased blood oxygen concentration stimulates peripheral chemoreceptors in the carotid and aortic bodies 19-29 Factors Affecting Breathing • motor impulses travel from the respiratory center to the diaphragm and external intercostal muscles • contraction of these muscles causes lungs to expand • expansion stimulates stretch receptors in the lungs • inhibitory impulses from receptors to respiratory center prevent overinflation of lungs 19-30 Factors Affecting Breathing • high blood PCO and high CSF H+ concentrations stimulate chemoreceptors of the respiratory center • alveolar ventilation increases • CO2 levels decrease in blood • H+ decrease in CSF 2 19-31 Respiratory Membrane • consists of the walls of the alveolus and the capillary 19-33 Diffusion Across Respiratory Membrane 19-13 Respiratory Infections • Most common cause of respiratory tract infection-Viruses – Self-limiting or life threatening – Lead to secondary bacterial infections Common Cold- most common cause- Rhinovirus Portal of entry- hands, nasal mucosa and conjunctivae of the eye Influenza-Upper and lower respiratory- Influenza A or Bflu like symptoms – If the virus is contained in droplets, it can bypass the upper respiratory tract and establish in the lungs resulting in pneumonia. -Epidemic or pandemic Immunization- Given to individual at high risk new strains appear against which the person lacks immunity. Pneumonia • Pneumonias- lower respiratory- Inflammation of lung tissues- alveoli and bronchioles • Lobar Pneumonia- Acute-occurs in healthy adults most commonly caused by Streptococcus pneumoniae involving an entire lobe. – Rapid onset, chill, high fever, and malaise Congestion, cough, watery sputum, and fine crackles can be heard during breath sounds. Legionnaires- Legionella pneumophila, found in warm standing water. Respiratory and CNS symptoms- leading to fatal pneumonia Atypical pneumonia- acute inflammatory changes Most common cause- Mycoplasma pneumonia Lower respiratory disorders • Pneumothorax- When air from the airways enter the pleural cavity causing collapse of the affected lung results – Spontaneous or result of direct injury to the chest. – Pleural Effusion- refers to a collection of fluid in the pleural cavity. • Clear, pus or blood • Hydrothorax- noninflammatory serous fluid most common cause is CHF • Hemothorax- presence of blood- 300ml-500ml – Complication of surgery, cancer, rupture of the aorta or injury Lower Reparatory • Atelectasis- refers to the incomplete expansion of a lung due to airway obstruction and lung compression. Breathing high concentration of oxygen, such as while on a ventilator, increases the rate which gases is are absorbed from the alveoli. • Pulmonary embolism- bloodborne substance lodges in a branch of the pulmonary artery and obstructs the flow. – Most common cause is due to a deep vein thrombosis – Thrombus, air, fat from the bone marrow after a fracture, or amniotic fluid.