Final answer:
Drinking hypertonic seawater leads to osmosis, where water leaves the blood cells to balance the solute concentration, causing dehydration. In contrast, a hypotonic solution can cause cells to swell, whereas an isotonic solution maintains cellular equilibrium.
Step-by-step explanation:
Drinking a hypertonic salt solution such as seawater is dangerous for someone who has been deprived of food and water because of osmosis. Osmosis is the passive transport process by which water moves across a cell membrane from an area of lower solute concentration to one of higher solute concentration. When a person drinks seawater, which has a higher concentration of solutes (salt) than the blood cells, it creates a hypertonic environment for the cells. Consequently, water diffuses out of the blood cells into the seawater-infused blood, potentially causing the cells to shrivel or crenate. This can lead to severe dehydration and imbalance in cellular function.
Hypotonic solutions, on the other hand, have a lower concentration of solutes compared to the cell's cytoplasm. If a person consumes a hypotonic solution, water would enter the cells, which could make them swell and potentially burst. The human body is better equipped to handle hypotonic situations as the excess water is typically excreted by the kidneys. An isotonic solution, where the solute concentration is the same inside and outside the cells, is ideal as it maintains the cells in a state of equilibrium with no net movement of water across the cell membrane, supporting overall cellular and bodily health.