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Kidney Function and Age - Physiology (view source)
Revision as of 19:40, 19 June 2010
, 19:40, 19 June 2010no edit summary
==Kidney Function in Newborns==
==Kidney Function in Newborns==
During pregnancy the placenta takes care of the homeostatic function of the foetus. The kidneys just produce the amniotic fluid. This means that the foetus has a very low GFR compared to adults. When born animals such as calves and piglets have relatively substantially lower GFR's compared to their adult counterparts. This takes some time to be corrected. In humans it is only at 2 to 3 years of age that children have relatively the same GFR and adults. The increase is mainly thanks to an increase in blood perfusion and activation of nephrons, inactive during foetal life.
During pregnancy the placenta takes care of the homeostatic function of the foetus. The kidneys just produce the amniotic fluid. This means that the foetus has a very low GFR compared to adults. When born animals such as calves and piglets have relatively substantially lower GFR's compared to their adult counterparts. This takes some time to be corrected. In humans it is only at 2 to 3 years of age that children have relatively the same GFR and adults. The increase is mainly thanks to an increase in blood perfusion and activation of nephrons, inactive during foetal life. This redued kidney capacity means that renal clearance of toxins and unwanted substances is not as efficent as it is in adults. This puts newborns at greater risk from some poisons etc. As with older animals this is an important consideration when administering drugs as many are excreted in the urine therefore if GFR is reduced their excretion will be also meaning an young animal will have higher plasma levels of the drug for longer.
This means their renal clearance of toxins and unwanted substances is not as efficent as that of adults. This puts them at greater risk from some poisons etc. Also as with older animals this is an important consideration when administering drugs as many are excreted in the urine therefore if GFR is reduced their excretion will be also meaning an young animal will have higher plasma levels of the drug for longer.