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"Glucose, glucose, everywhere, nor any speck to utilize" is a phrase made up by one of the authors ...

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berenicecastro:
Question 1What are oropharynx receptors, which hormone do they decrease, and how is it known that they exist? If a person stranded on a desert island drank seawater to try to quench his thirst, how would this affect the oropharynx receptors?

Question 2"Glucose, glucose, everywhere, nor any speck to utilize" is a phrase made up by one of the authors working on this test question. Similar to the irony of not being able to prevent dehydration by drinking seawater, people with untreated diabetes mellitus are unable to prevent starvation even though there is a large amount of glucose surrounding their cells; as if that is not bad enough, dehydration is also a problem. Explain why there is glucose in the urine of such people, why glucose is not present in the urine of normal people, and why diabetics become dehydrated.

lcapri7:
Answer 1Oropharynx receptors inhibit the sense of thirst when they come in contact with cool water. They also inhibit secretion of vasopressin (ADH). They have not been identified anatomically, but presence of even a small amount of cold water in the mouth and pharynx is known to satisfy thirst even if the water is not absorbed and thus does not actually alleviate dehydration. Presence of receptors that inhibit the thirst sensation are the best guess as to how this works. Presumably drinking seawater would temporarily reduce the sense of thirst by the same proposed mechanism.

Answer 2Glucose is in the urine simply because the plasma concentration exceeds the number of glucose transporters in the kidney tubules, because plasma glucose is unusually high. Normal individuals are able to reabsorb all the glucose in the filtrate because plasma glucose concentrations are normally low (normal body cells absorb glucose, diabetic cells do not). Glucose in the filtrate raises the osmolarity of the filtrate, which decreases the relative osmotic gradient for reabsorption of water; thus more water is lost in the urine leading to dehydration.

Allie Newman:
Thanks

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