Proximal tubule: ~65% Na+/H+ antiporter Loop of Henle: ~25% Na+/K+/2Cl- pump DCT: ~7% Na-Cl transporter Collecting duct: 3% eNacs

functions

• Fluid balance
• Electrolyte balance
• BP regulation
• Acid-base balance
• Removal of toxins
• EPO production
• Activation of vitamin D → calcium absorption
• Gluconeogenesis

3 processes

• Filtration
• Reabsorption and secretion

Renin

• Released from juxtaglomerular cells (afferent arteriole) – full of renin granules