Outline the factors that determine the composition and volume of glomerular filtrate in a normal person.
The volume and composition of the glomerular filtrate are best explained by referring to the
equation: Glomerular Filtration = Kf x net filtration pressure. Then describing the factors that
affect each part of the equation e.g. hydrostatic pressure, oncotic pressure, factors that
influence the filtration coefficient e.g. surface area
Glomerular filtrate is an ultrafiltrate of plasma and factors that affect the passage of proteins
and other molecules should be discussed
Extra marks were given for an explanation of filtration fraction and short facts about GFR in
paediatric patients and the elderly.
No marks were given for any discussion of drugs.
Syllabus D2b
Reference; Power and Kam 1st edition p 197-199
Glomerular ultrafiltration is described by the Starling equation:
GFR = Kf [ (Pgc - PBC) - σ(Πgc - Πi) ]
where
Glomerular filtration of solutes is affected by:
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