Control Of Respiratory Function
- 1. Chapter 20 Control of Respiratory Function
- 2. Lung Functions Gas exchange Moves O 2 into blood Removes CO 2 from blood Blood storage Regulate vasoconstricting substances Bradykinin Angiotensin II Heparin
- 3. Conducting Airways Move air into lungs Warm and humidify air Trap inhaled particles
- 4. Respiratory Airways Bronchioles Alveoli Gas is exchanged with the blood
- 5. Membranes and Cavities Parietal pleura Visceral pleura Pleural space (between pleurae) Mediastinum
- 6. Respiratory Muscles Diaphragm Accessory muscles of inhalation External intercostals Scalene Sternocleidomastoid Accessory muscles of exhalation Internal intercostals Abdominal muscles
- 7. Compliance How easily lungs can be inflated Depends on: Elastin and collagen fibers Water content Surface tension
- 8. Surfactant Reduces Surface Tension
- 9. A ManтАЩs Lungs Were Damaged During a Fire тАж He developed severe respiratory distress The doctor said smoke inhalation had caused an inflammation of his alveoli The damage had also destroyed some of his surfactant What had happened to his lung compliance? Why was he given positive-pressure ventilation?
- 10. Lung Volumes Tidal volume Inspiratory reserve Expiratory reserve Residual volume
- 11. Lung Capacities Vital capacity Inspiratory capacity Functional residual capacity Total lung capacity
- 12. Dynamic Lung Function Forced vital capacity Forced expiratory volume FEV 1.0 Minute volume Maximum voluntary ventilation
- 13. Gas Exchange Oxygen moves from alveolar air into blood Carbon dioxide moves from blood into alveolar air
- 14. Ventilation and Perfusion A child has inhaled a peanut, blocking her left primary bronchus How will the ventilation in her two lungs change? How will the composition of the air in her two lungs differ? Which lung should she send more blood to? How should her body alter perfusion of the lungs?
- 15. Ventilation-Perfusion Mismatching Blood goes to parts of the lung that do not have oxygen to give it Blood does not go to parts of the lung that have oxygen
- 16. Blood GasesтАФOxygen Dissolved oxygen = PaO 2 or PO 2 Normal value >80 mm Hg Oxygen bound to hemoglobin = oxyhemoglobin Normal value 95% to 97% saturation
- 17. Hemoglobin Holds 4 Oxygen Molecules O 2 O 2 O 2 How saturated is this molecule of hemoglobin? How could a person have a hemoglobin saturation of 95%?
- 18. Oxygen Capacity Amount of oxygen the blood can hold What is the oxygen capacity of normal blood? What is the o xygen capacity of anemic blood?
- 19. Oxygen Release If the blood released half of its oxygen to the tissues тАж How much oxygen would the normal tissues receive? How much would the anemic person's tissues receive?
- 20. Oxygen Release (cont.) Most body tissues have a PO 2 of 40-60 mm Hg How much oxygen does the normal blood release at a PO 2 of 40 mm Hg? The anemic blood?
- 21. Oxygen Affinity How tightly the hemoglobin holds onto the oxygen Which of these hemoglobin samples has the highest o xygen affinity? Which will release the most o xygen to the tissues? A B C
- 22. Blood GasesтАФCarbon Dioxide Dissolved carbon dioxide = PaCO 2 or PCO 2 Normal value 35тАУ45 mm Hg Carbon dioxide bound to hemoglobin = carbaminohemoglobin Carbonic acid яГЯяГа bicarbonate ion and H + When you exhale you remove CO 2 from your blood and also decrease the amount of carbonic acid, raising your blood pH
- 23. Respiratory centers pneumotaxic apneustic stops inspiration; begins exhalation lungs deflate stretch receptors note decreased lung volume begins inspiration lungs inflate stretch receptors note increased lung volume
- 24. Chemoreceptors Can Adjust Respiration Rate Central chemoreceptors Measure PCO 2 and pH in cerebrospinal fluid Increase respiration when PCO 2 increases or pH decreases Peripheral chemoreceptors Measure PO 2 in arterial blood Increase respiration when PO 2 <60 mm Hg
- 25. You Are Caring for a COPD Client тАж He has chronically high PCO 2 He is being given low-flow oxygen and complains all the time that he тАЬneeds more air,тАЭ so you turn up his oxygen When you check on him later, he is unconscious and not breathing! What happened?