Seawater Has an Osmolarity of Around 1000 MOsm, Mostly from Dissolved

question 60

Multiple Choice

Seawater has an osmolarity of around 1000 mOsm, mostly from dissolved sodium. Given what you know about the osmolarity in most of the cells in the body, why is it dangerous to drink seawater?

• A)In the nervous system, the additional extracellular sodium concentration would slow down the normal flow of sodium ions used to generate action potentials.
• B)In the digestive system, the seawater would draw more water out of the bloodstream than would be absorbed, leading to severe dehydration.
• C)In the cardiovascular system, the higher sodium levels would decrease the pressure in the arteries making it more difficult to get blood to the systemic capillaries.
• D)In membrane transport, the increased sodium concentration would slow down secondary active transport of glucose into cells.
• E)In the renal system, the osmolarity of the medulla of the kidney would become even more concentrated.

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