BIOL 3402 Lecture Notes - Lecture 3: Pulmonary Compliance, Infant Respiratory Distress Syndrome, Spirometer
Document Summary
Airflow governed like bloodflow: flow inversely proportional to resistance, high to low pressure, low-energy. Atmospheric pressure drives respiration: weight of air above us, 760 mm hg at sea level, or 1 atm. Higher atm at lower elevations: boyle"s law. Compliance: how easily the lung can expand. Resistance/elastance: how easily the lung is able to recoil. Quiet breathing: only moves a bit, increase volume by 500 ml. So 500 ml of air flow in: volume raises = pressure dropping in lungs. Forced breathing: accessory muscles raise intrapulmonary pressure as high as +40 cm h2o. Histamine, parasympathetic, cold air, chemical irritants stimulation. Suffocation: anaphylactic shock or asthma, pulmonary compliance. Only air in alveoli for gas exchange. Anatomical dead space: no gas exchange. Some pulmonary diseases alveoli can"t exchange: physiologic (total) dead space. 500 ml in, 150 ml stays in dead space, 350 ml to alveoli. Alveolar ventilation rate (avr: avr lower than volume.
