A fall in the GFR rate activates the
a)	JG cells to release renin	b)	JG cells to release aldosterone
c)	JG cells to release epinephrine	d)	JG cells to release nor-epinephrine

(a)

JG cells to release renin.

The kidneys have built in mechanisms for the regulation of glomerular filtration rate. One such efficient mechanism is carried out by juxta glomerular apparatus (JGA), JGA is the special sensitive region formed by cellular modification in the distal convoluted tubule and the afferent arteriole at the location of their contact. A fall in GFR can activate the JG cells to release renin, which can stimulate the glomerular blood flow and there by GFR back to normal