NEET Revision Kit: Rapid Recall

1. The "Gradient" Cheatsheet

  • Cortex Osmolarity: 300 mOsmol/L.
  • Medulla Osmolarity: 1200 mOsmol/L.
  • Main Solutes: NaCl and Urea.
  • Concentrating Driver: Counter Current Mechanism (Henle's Loop + Vasa Recta).

2. Regulation Pathways

  • RAAS: Low GFR →\rightarrow Renin →\rightarrow Angiotensin II →\rightarrow Aldosterone →\rightarrow Na+/Water Reabsorption →\rightarrow BP Increases.
  • ADH (Vasopressin): High Osmolarity (Thirst) →\rightarrow ADH →\rightarrow Water Reabsorption (DCT/Collecting Duct) →\rightarrow Urine Concentrated.
  • ANF: High BP →\rightarrow Atrial Wall Stretch →\rightarrow ANF →\rightarrow Vasodilation →\rightarrow BP Decreases (Checks RAAS).

3. Nephron Function Quick-Look

  • PCT: 70-80% Reabsorption, Brush Border, pH balance (Secretion of H+, K+).
  • Descending Limb: Permeable to Water (Concentrates filtrate).
  • Ascending Limb: Impermeable to Water (Dilutes filtrate).
  • DCT: Conditional Na+/Water reabsorption.
  • Collecting Duct: Urea recycling, final water recovery.

4. Disorder Keywords

  • Uremia: Urea in blood.
  • Hematuria: Blood in urine.
  • Glycosuria/Ketonuria: Diabetes Mellitus.
  • Glomerulonephritis: Inflammation of glomeruli.
  • Calculi: Oxalate stones.