In: Anatomy and Physiology
Discuss fluid and electrolyte balance in the human body
Fluid and electrolyte balance:
Total body water =Intracellular fluid + Extracellular fluid.
Extracellular fluid =interstitial + intravascular + transcellular .
Human body has 2/3 of water (40 L for a 70 kg person).
Total amount of water and solutes in each compartment remains constant.
Water content and movement is tied to electrolyte and solute concentration and movement.
Balance includes both input and output. Inputs are food ,drink.outputs are urine,sweat,skin,feces,expired air.
Urine volume is controlled by GFR,reabsorption of water by tubules.It is controlled by hormones namely ADH and aldosterone.
Electrolytes:
Sodium,calcium,potassium and magnesium are cations. Chloride,proteins are anions.
Electrolytes function as building blocks,regulation of metabolic pathway,nerve and muscle membrane potential.
ECF=Na+,Cl-,HCO3-.
ICF=K+,Mg+,proteins.
Osmotic pressure and hydrostatic pressure controls movement of water between compartments.
Fluid imbalance:
*Dehydration~output more than input
*Water intoxication~input more than output
*Edema~accumulation of water in ECF