When malnutrition, protein intake is insufficient, and plasma osmotic pressure is reduced, why will it cause tissue edema? Please explain in detail?

Analysis: Osmotic pressure refers to the attraction of solute particles in solution to water, and osmotic pressure depends on the number of solute particles in unit volume solution. When malnutrition, insufficient intake of protein, and decreased plasma osmotic pressure, it will cause too much water to enter the tissue fluid, thus causing tissue edema.