MEDICAL PHYSIOLOGY

Detailed explanation-1: -Cells in macula densa contain chemoreceptors that continuously monitor the sodium chloride (NaCl) concentration in the filtrate, so they are also known as salt sensors. Decreased sodium chloride levels in the tubular filtrate are caused by decreased blood pressure.

Detailed explanation-2: -Macula densa cells are renal sensor elements that detect changes in distal tubular fluid composition and transmit signals to the glomerular vascular elements. This tubuloglomerular feedback mechanism plays an important role in regulating glomerular filtration rate and blood flow.

Detailed explanation-3: -In the distal convoluted tubule is located the macula densa: it has longer cells and cytoplasmic granules. Close to it there are segments of afferent and efferent arterioles that have a greater amount of cytoplasmic granules. These granules correspond to renin, the proteolytic enzyme that is synthesized there.

Detailed explanation-4: -The cells of the macula densa are sensitive to the concentration of sodium chloride in the distal convoluted tubule.