To explain:
The osmolarity of sea water is more than four times of osmolarity of blood. Explain the reason why a person can’t drink sea water. Most of the water is saline that means seawater and a very little amount is fresh water which is available to drink.
Concept introduction:
Osmolarity refers to the concentration of the solution, which is the total number of solute particles in 1 liter of solvent. Osmolarity of seawater is much higher than the osmolarity of blood.
Explanation of Solution
The human body is composed of approx 60% of water. This water is separated into two compartments: the extracellular fluid (fluid outside of cells) and intracellular fluid (fluid inside the cells). The water can travel to and fro through a semi-permeable membrane and keeps the cells and outer space isotonic. The water can freely pass through the membrane but some ions cannot.
It is bad for the body to drink sea water because the concentration of solutes is higher in seawater than the solute concentration in the body. The cells require an isotonic medium to perform properly but when the body consumes the water with high salt concentration, the major net gain in the body is of the salt. This makes the medium “hypertonic for the cells”. Due to high salt concentration in extracellular space, the water starts moving out of the cells to create equilibrium. This condition causes dehydration in the body.
If seawater is consumed, the high osmolarity difference between blood and seawater causes dehydration to the cells. Due to thirst, the cells are already facing the crisis of water, the addition of hypertonic water makes the conditions worse for the cells. So consumption of saline water is not beneficial to remove thirst feeling.
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Chapter 36 Solutions
Biology: Life on Earth with Physiology (11th Edition)
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- Two solutions are separated by a semipermeable membrane that is permeable only to water. The two solutions are: Solution A = 150 mM KCl Solution B = 150 mM Angiotensin (a 7 amino acid polypeptide) Which of the following would best explain the net movement in this situation? - water will move from the KCl side to Angiotensin side - water will move from Angiotensin side to KCl side - The Cl- ion will move to the angiotensin side until there is 75 mM Cl- on each side - Since Angiotensin is not an ion, it can move through the membrane - There is no net water movement as the concentrations are the same on both sidesarrow_forwardSome animals living in water excrete nitrogen as ammonia. Land animals, which must conserve water, excrete urea or uric acid. How does excretion of these molecules aid in water conservation?arrow_forward
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