Final answer:
The statement that blood plasma osmolarity is higher than intracellular fluid osmolarity is false; osmolarities are usually maintained at equal levels to prevent cellular damage. Plasma proteins like albumin contribute to BCOP and do not cross the capillary walls easily, affecting fluid exchange. Sodium ions are highest in the extracellular fluid.
Step-by-step explanation:
Answering the question of whether blood plasma osmolarity is higher than intracellular fluid osmolarity, it is false. The osmolarity inside cells, or the intracellular fluid, is usually maintained in a way that it is equal to the osmolarity of extracellular fluids, including blood plasma, to prevent cellular shrinking or swelling. However, specific conditions affect this balance, such as in a hypertonic solution, where the extracellular fluid has a higher osmolarity than the cell’s cytoplasm, causing water to leave the cell.
Additionally, plasma proteins, like albumin, do not normally cross the capillary wall because of their large size and the selective permeability of the capillary endothelium. Therefore, these proteins remain in the blood, contributing to the blood's colloidal osmotic pressure or the blood colloid osmotic pressure (BCOP), which is crucial for maintaining water balance between blood and tissue fluid.