Metabolism
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An early morning jog
Key points from this exercise:
The ratio of carbon dioxide formed : oxygen consumed (the respiratory quotient, RQ) is:
0.7 when fatty acids are being metabolised
1.0 when glucose is being metabolised
Measurement of RQ thus permits determination of the relative amounts of fat and carbohydrate being metabolised
In the fasting state blood glucose is maintained by:
breakdown of liver reserves of glycogen
gluconeogenesis from glycerol and amino acids
provision of fatty acids to tissues as an alternative fuel
In the fasting state fatty acids are provided to tissues from the hydrolysis of adipose tissue triacylglycerol
In the fed state fatty acids are provided to tissues (mainly for storage) as triacylglycerol in chylomicrons (and other plasma lipoproteins)