ANATOMY

Detailed explanation-1: -Specialized cells (macula densa) of distal tubules lie adjacent to the JG cells of the afferent arteriole. The macula densa senses the concentration of sodium and chloride ions in the tubular fluid. When NaCl is elevated in the tubular fluid, renin release is inhibited.

Detailed explanation-2: -The cells of the macula densa are sensitive to the concentration of sodium chloride in the distal convoluted tubule.

Detailed explanation-3: -There is a region of specialized smooth muscle cells (JG cells) in the afferent arteriole which, along with a set of columnar cells called the macula densa in the adjacent segment of distal convoluted tubule, sense changes in blood pressure and sodium concentration.

Detailed explanation-4: -Macula densa is a region where DCT touches the glomerulus. Its function is to sense sodium chloride concentration in the filtrate and activate tubuloglomerular feedback which adjusts GFR to regulate the concentration of tubular sodium and chloride.