The Juxtaglomerular (JG) apparatus functions within renal physiology to maintain Glomerular Filtration Rate (GFR) homeostasis via tubuloglomerular feedback, a mechanism relying on the macula densa's sensing of urinary sodium chloride concentration. When GFR rises and intratubular NaCl increases, macro dense cells secrete adenosine to trigger afferent arteriole vasoconstriction; conversely, low NaCl levels stimulate JG cell granular cells to release renin for Angiotensin II production and mild efferent constriction. This system operates within the broader framework of kidney autoregulation alongside the myogenic mechanism, ensuring stable filtration despite systemic hemodynamic fluctuations such as changes in blood pressure.
The Juxtaglomerular (JG) apparatus functions within renal physiology to maintain Glomerular Filtration Rate (GFR) homeostasis via tubuloglomerular feedback, a mechanism relying on the macula densa's …