Now recall that the maculodeensa are part of the juxtaglomeral apparatus, the structure found in the nephron that regulates and controls the functionality of the nephron. So the question is what exactly is the purpose of these purple cells, the macular densa cells? Well, they serve two important functions. Firstly, they can actually sense any fluctuation in sodium chloride concentration inside the lumen inside our distal convoluted tubule. And if the sodium chloride concentration inside the tubule drops, then what the maculus densa cells do is they are capable of stimulating the African arterial, this blood vessel right here, to actually dilate an increase in diameter. And that not only decreases the resistance of the blood flow, but it also increases the amount of blood that reaches arglomerilus and that increases the hydrostatic pressure in araglomerilus.