COURSE OBJECTIVES

The objectives of this course are to have students master the following topics and to apply this knowledge to problems and case studies relevant to clinical physiology.

INTRODUCTION

• Exchange of metabolized gases; typical rates of oxygen consumption and carbon dioxide production
• Aspects of respiratory system function related to gas exchange
• Other functions of the respiratory system

RESPIRATORY VENTILATION

• Lung volumes and capacities: definitions, measurement, and typical values
• Ventilation rate: definitions, measurement, and typical values
• Airway function; secretory gland and cilia function
• Respiratory pressures (intralveolar and intrapleural) and muscle contraction in inspiration and expiration; effect of pneumothorax
• Respiratory system compliance: definition, contribution of lung and chest wall tissue, role of surface tension and pulmonary surfactant, typical values
• Air movement and airway resistance: definition, determinants, role of autonomic nervous system, mechanical factors, typical values
• Pathophysiology: physiological basis of restrictive, obstructive, and neurogenic diseases; basis of changes in emphysema
• Pressures during the respiratory cycle in health and in diseases of ventilation
• Work of breathing

ALVEOLAR GAS EXCHANGE

• Role of diffusion and chemical reactions in blood in alveolar exchange
• Alveolar diffusion: mechanism, diffusing capacity; role of area, diffusion distance, solubility, and diffusion coefficient
• O2, CO2, and CO diffusing capacity at rest and in exercise
• Composition and partial pressures in inhaled, tracheal (saturated inhaled), alveolar, and exhaled gases
• Dead space, wasted ventilation, and alveolar ventilation
• Factors determining alveolar partial pressures; the alveolar air equation
• Fick’s law applied to exchange of oxygen and carbon dioxide
• Typical values (fraction, partial pressure) of inhaled and alveolar O2, CO2, and H2O

BLOOD GAS TRANSPORT

• Oxygen transport by physical solution and by binding to hemoglobin
• Oxyhemoglobin dissociation curve: shape, shifts, physiological significance
• Typical values of hemoglobin, blood oxygen content, and blood oxygen partial pressures
• Cyanosis, anemia, polycythemia; characteristics of fetal hemoglobin
• Effect of carbon monoxide
• Carbon dioxide transport by physical solution, protein binding, carbonic acid, bicarbonate ion; role of carbonic anhydrase
• Carbon dioxide dissociation curve: shape and shifts
• Typical values of carbon dioxide content and partial pressures in blood
• Gas movement in pulmonary and systemic capillaries; chloride shift

PULMONARY CIRCULATION

• Pulmonary blood flow, blood pressure, and vascular resistance
• Control of pulmonary vascular resistance
• Regional blood flow distribution
• Pulmonary capillary fluid exchange; pulmonary edema

ALVEOLAR-ARTERIAL EQUILIBRATION

• Hypoxia: definition and physiological causes
• Alveolar-arterial oxygen partial pressure difference
• Regional variations in alveolar ventilation and blood flow
• Causes of AaD-O2: diffusion limitation, shunt, VA/Q nonuniformity (mismatch)
• Alveolar-capillary block, venous admixture, alveolar and physiological dead space
• Carbon dioxide equilibration
  Measurement of contributors to AaD-O2

NEUROGENESIS AND REGULATION OF RESPIRATION

• Neural structures: respiratory and pneumotaxic centers; reticular activating system and other CNS contributors
• Lung mechanoreceptor reflexes
• Chemical regulation of ventilation:
  • oxygen chemoreceptors and related reflexes
  • carbon dioxide chemoreceptors and related reflexes
  • H+ chemoreceptor and pH related reflexes

PROBLEMS and CALCULATIONS

• Ability to apply knowledge of respiratory function to diagnosis based on respiratory function tests and blood gas analysis