Question

Both of the regular intravenous solutions administered in medicine, normal saline and lactated Ringers solution, are isotonic, such as seen in the middle image here. Why is this important?

a) Isotonic solutions prevent cell shrinkage or swelling by maintaining balance with the cell's internal environment.
b) Hypotonic solutions promote cell shrinkage, ensuring stability.
c) Hypertonic solutions facilitate water influx into cells.
d) Isotonic solutions have no impact on cellular conditions.

Answer 1

Normal saline and lactated Ringer's are isotonic solutions used in medicine to maintain the balance of water in cells by matching the osmolarity of the cells, thus preventing cell shrinkage or swelling.

Step-by-step explanation:

Isotonic solutions, such as normal saline and lactated Ringer's solution, are crucial in medicine because they have the same osmolarity as the cells in our body. This similarity in osmolarity means that there is no net movement of water into or out of the cells, which is important because it prevents cells from shrinking or swelling, thus maintaining a balance with the cell's internal environment. In a hypertonic solution, the extracellular fluid has a higher osmolarity than the cell's cytoplasm, causing water to leave the cell and potentially leading to cell shrinkage. Conversely, in a hypotonic solution, water enters the cell, causing it to swell. Both these scenarios can compromise cellular function and are thus undesirable in an intravenous therapy context where the goal is to stabilize the patient without causing additional cellular stress.