Body fluid compartments video
Interstitial fluid has an ionic composition similar to that of plasma. Only a small proportion of the body’s potassium is present in plasma, but the concentration of potassium ions is crucial to cardiac and neuromuscular function. The protein in plasma is responsible for the intra vascular colloid osmotic pressure, a major determinant of the movement of fluid across the capillary endothelium.
Water and electrolytes move freely between plasma (intravascular compartment) and the interstitial fluid, but plasma proteins enter the interstitial fluid only when the capillary endothelium is damaged, for example as a result of septic shock or burns. Plasma contains proteins (chiefly albumin) and ions (mainly sodium, chloride, and bicarbonate). Physiologically, these three compartments of body water are interdependent. The extra cellular fluid is sub divided into Intravascular (plasma) comprising 2/3 of extra cellular fluid and Interstitial which comprises 1/3 of extra cellular fluid. Extra cellular fluid, comprising 1/3 of total body water.Intracellular fluid, comprising 2/3 of total body water.Total body water is further divided into two: The total body water in neonates is 80%-85%, which is higher than in adults. Females have lower body water (45 –60%) because of the high fat content of their body. In regard to this, 55% – 60% of body weight for a 70 Kg young man is water. The total body water constitutes 50 – 85% of total body weight depending on age and lean body mass (muscle mass). Daily average water and electrolyte exchanges.