Reabsorption & Secretion in the Nephron - Introduction

Reabsorption & Secretion in the Nephron - Introduction

Reabsorption

• Removes solutes and water from the tubular fluid and returns them to the blood;
• It reclaims much of the water, ions, and nearly all of the nutrients that are filtered.

Secretion

• Moves solutes from the blood and nephron tubule cells into the tubular fluid;
• Secretion is important for removal of substances that aren't filtered (such as drugs and metabolites) and for fine-tuning the final urine composition.

Key principles of transport:

• Vasculature:
  – Efferent arteriole leaves glomerulus, gives rise to peritubular capillaries.
  – Peritubular capillaries give rise to vasa recta of juxtamedullary nephrons.
  – Vasa recta drains deoxygenated blood into the interlobular vein.