Final answer:
An isotonic solution is vital for biological systems as it maintains equilibrium between extracellular and intracellular fluid osmolarity, ensuring no net water movement and maintaining normal cell structure and function. In medical settings, IV solutions like normal saline and lactated Ringer's are isotonic to blood to avoid disrupting this balance.
Step-by-step explanation:
An isotonic solution is one where the extracellular fluid has the same osmolarity as the cell, meaning the concentration of solutes is equal both inside and outside of the cell. This balance is crucial because it ensures there is no net movement of water into or out of the cell, although individual water molecules will still move across the cell membrane. This property is especially important in intravenous solutions like normal saline and lactated Ringer's, which are designed to be isotonic with the blood to maintain cell structure and function when administered medically.
Blood serves as a buffered solution, primarily consisting of carbonic acid (H2CO3) and bicarbonate ions (HCO3-) that regulate pH. This buffering system allows blood to neutralize added acids or bases, keeping the pH levels stable. Therefore, isotonic solutions do not decrease the pH of the blood, as previously mentioned, but rather they maintain the pH to ensure the normal function of blood cells and the avoidance of unwanted material exchange due to osmotic pressure differences.