Final answer:
The statement is false as blood plasma contains a high concentration of proteins, which do not cross into the interstitial fluid in appreciable amounts due to the semi-permeable nature of capillary walls.
Step-by-step explanation:
The statement that interstitial fluid contains an appreciable amount of protein anions, whereas blood contains hardly any, is false. In reality, blood plasma has a high concentration of protein, which contributes to its osmotic pressure and is not typically found in significant amounts in the interstitial fluid due to the selectivity of the capillary walls. They are permeable to water, inorganic ions, and small organic molecules, but largely impermeable to large organic molecules such as proteins. The interstitial fluid does have a higher concentration of diffusible anions compared to cations, but the protein content is relatively much lower than that of the blood plasma.
Blood plasma and interstitial fluid are components of the extracellular fluid (ECF) and share many solutes like sodium, chloride, and bicarbonate, but plasma contains a higher concentration of proteins that exert a colloidal osmotic pressure. The capillary walls act as barriers preventing plasma proteins from freely moving into the interstitial space, which maintains the lower protein concentration in the IF compared to the plasma.