Explain the factors that influence Glomerular Filtration Rate
These include:
1) Renal blood flow: A large proportion of blood flows into the glomerulus. The greater the rate of flow of blood into the glomerulus, the greater will be the GFR.
2) Sympathetic stimulation: If there is a mild or moderate sympathetic stimulation of the kidney, the GFR decreases. But if there is a strong sympathetic stimulation, glomerular pressure is reduced and the GFR falls to zero.
3) Afferent arteriolar constriction: At ferent arteriolar constriction decreases the rate of blood flow into the glomerulus, decreases the glomerular pressure and the GFR.
4) Efferent arteriolar constriction: Constriction of the efferent arteriole increases the glomerular pressure and the GFR.
5) Arterial pressure: Though an increase in the arterial pressure causes an increase in GFR but the effect is minimized because of autoregulation of the kidney. Rise of arterial pressure increases constriction of afferent arteriole. This prevents a major rise in glomerular pressure causing the GFR to increase to only 15 to 20 percent.