Diameter of Afferent Blood Vessel & Glomerular Filtration Rate

(arrows mean increase or decrease)

Ý Large diameter

Ý high volume

Ý high net pressure

Ý fast GFR (rate)

so

there is no time to reabsorb

Ý high solute concentration

Ý high osmotic pressure

at the juxtaglomerular apparatus

so vasoconstrictor will be released

ß Small diameter

ß low volume

ß low net pressure

ß slow GFR (rate)

so

there is too much time to reabsorb

ß low solute concentration

ß low osmotic pressure

at the juxtaglomerular apparatus

so vasodilator will be released