Explain the autoregulatory mechanism of $GFR$.

(N/A) The kidney possesses a built-in mechanism for the regulation of glomerular filtration rate $(GFR)$,known as autoregulation.
This process is primarily managed by the juxtaglomerular apparatus $(JGA)$.
The $JGA$ is a specialized microscopic structure located at the contact point between the vascular pole of the renal corpuscle and the distal convoluted tubule $(DCT)$ of the same nephron.
When $GFR$ decreases,the $JGA$ cells are activated to release the enzyme renin.
Renin initiates the renin-angiotensin mechanism,which leads to the constriction of efferent arterioles and systemic vasoconstriction,thereby increasing glomerular blood pressure.
This increase in blood pressure restores the $GFR$ to its normal level.