Capacidade de Filtração Renal: 200 Litros de Sangue por Dia

Each kidney contains ~1 million nephrons, the functional filtration units.

Filtration Process

1. Glomerulus: Capillary tuft filters plasma (water, electrolytes, small molecules) — retains cells/proteins. GFR ~125 mL/min (180 L/day).
2. Proximal Tubule: Reabsorbs 65% filtered Na⁺, water, glucose, amino acids, bicarbonate.
3. Loop of Henle: Countercurrent multiplication → medullary gradient → water reabsorption.
4. Distal Tubule/Collecting Duct: Fine-tune Na⁺, K⁺, H⁺, water (aldosterone, ADH).

Net Output

• Filter ~180–200 L plasma/day.
• Excrete 1–2 L urine (99% reclaimed).
• Regulate: volume, osmolarity, pH, electrolytes, toxins.

Clinical Relevance

GFR decline = CKD staging. Creatinine-based eGFR estimates filtration. Hyperfiltration (diabetes) → long-term damage.

Kidneys are high-capacity, precision filters maintaining internal milieu.