DASC20010 Lecture Notes - Lecture 17: Breathing, Lung Volumes, Gas Exchange

• School: University of Melbourne
• Department: Animal Science
• Course: DASC20010
• Professor: Peter Cakebread

Document Summary

Pulmonary ventilation: pulmonary ventilation (ml/min)= tidal volume (ml/breath) x respiratory rate (breaths/min, end-inspiratory vol end expiratory vol = tidal volume, a sheep: pulmonary ventilation, = tidal volume (200ml) x respiratory rate (40 breaths/min)= Lungs also has to match the perfusion to the ventilation. Lungs match the blood flow at the same time they are changing ventilation. Mechanisms to keep it balanced: local control of individual airways supplying specific alveoli, optimizes efficiency of oxygen and carbon dioxide exchange, direction of effect is opposite to that in systemic arterioles. What pulmonary arteries are doing- seems to be the opposite of what is happening in the systemic system. Systemic tissues- muscles etc- when there is large metabolic activity- oxygen levels drop and carbon dioxide levels rise: vasodilation of alveoli, more blood flow taking place because vasodilation of arterioles. In lungs it is the other way round. Gas exchange: partial pressures: mixed gases in air & water (blood) partial pressures sum to atmospheric pressure.