Discuss the factors that influence filtration across the glomerular basement membrane.

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College Answer

It was expected this answer would involve discussion about membrane structure, the unique 
blood vessel structure (afferent and efferent arterioles allowing a high net pressure to be 
maintained) and Starlings forces all influencing ultrafiltation. Better answers included comment 
on mesangial cells contraction to decrease surface area ( caused by angiotensin 2). Details 
regarding molecular weight cut offs (> 7000 Da are not filtered freely) gained additional credit.