Supporting Metabolism

• Role of CV & resp system – meet metabolic demands
• RQ = ratio CO2 produced to O2 consumed by cells per min
• RER = VCO2 produced/VO2 consumed during expiration
• RER > 1 = anaerobic resp, RER<1 = aerobic resp
• RER indicates substrates used for metabolism, measured using indirect calorimetry, gas volume & composition analysis
• Typical O2 consumpt = 250ml/min & typical CO2 production = 200ml/min
• Glucose – anaerobic & aerobic metabolism; proteins & FAs – aerobic metabolism only
• HR clinically measured using ECG (measures overall electrical activity of heart) or pulse transducer (senses pressure wave down artery)
• Pulm function tests use spirometry, can analyse expired gas composition for measures during exercise
• Typical tidal vol = 500ml typical resp freq = 15 breaths per min
• VO2 consumption per min = VO2 in – VO2 exp or VE x (fraction inspired O2 – fraction expired O2)
• VCO2 produced per min = VE x fraction expired CO2
• Spirometry graph – slope = vol of O2 consumed
• Exercise cause increase in resp freq & tidal vol so steeper & more frequent peaks on spirometry graph (tidal vol contributes most to increasing VO2
• VO2 max = max vol O2 can be consumed, indicates fitness
• Pulm Circulation Functions – O2 & CO2 exchange, capacitance, filtration, vasoactive substance synthesis & metabolism
• Characteristics of Pulmonary Circulation – highly affected by gravity, linked to LV function, flow equal to CO, lower resistance than systemic