HSC 4555 Lecture Notes - Lecture 12: Hypercalcaemia, Oliguria, Fluid Balance
Document Summary
Chapter 24: fluid and electrolyte homeostasis and imbalances. Fluid homeostasis is a dynamic process that includes fluid intake and absorption, fluid distribution across body fluid compartments, fluid excretion, and, in some individuals, fluid loss through abnormal routes. Habit and thirst are important regulators of fluid intake. Individuals who are unable to control their own fluid intake (such as those receiving fluids intravenously and immobile or unconscious patients) are at high risk for fluid imbalance. Fluid (water and small particles) moves back and forth between the vascular and interstitial areas by filtration at the capillaries. Capillary hydrostatic pressure is the primary force promoting fluid movement from the capillaries to the interstitial fluid. Plasma colloid osmotic pressure is the primary force that causes interstitial fluid to move back into the capillaries. Water moves in and out of cells by osmosis. Electrolytes do not move freely across cell membranes but are transported by membrane channels and carriers.