Intestinal Fluid Handling

Intestinal Fluid Handling

Daily Fluid Dynamics

  • Total Fluid Entering Proximal Small Intestine: 9 L/day

    • Ingested: 2 L (diet)

    • Internal Secretions: 7 L

Chyme Characteristics

  • Duodenal Chyme: Typically hypertonic due to meal content.

  • Ileal Chyme:

    • Adjusts osmolality to match plasma.

    • Major absorption of dietary fat, carbohydrates, and protein.

Changes in Fluid Volume

  • Volume at Ileum: Decreases to 1 L/day entering the colon.

  • Volume in Colon: Reduced to 100 mL daily due to colonic absorption.

Consequences of Overload

  • Chyme Overload: Can exceed small intestine water absorption capacity, leading to diarrhea.

  • Colonic Absorptive Capacity: Approximately 5 L daily.

Importance of Colonic Transport

  • Critical for maintaining water and electrolyte balance.