Question

An impassioned astronaut, who is well aware of some "kidney problem", goes to the army base for a battery and a physical exam. You are asked to fast for twelve hours overnight and collect all of your urine in the morning. During the last hour period, your urine volume is 1200 ml and your urine osmolality is 60 mosm / I. Based on these observations, be the bus ticket to return home.

What could be "wrong" with your kidney that explains your inability to form concentrated urine?

Why did the space program reject it?

Answer 1

What could be "wrong" with your kidney that explains your inability to form concentrated urine?

Osmolarity of urine- it is used to check the level of water and particles in the urine. The more level of osmolarity mean concentrated urine and less level of osmolarity mean dilutes urine.

Normal level of urine osmolarity is 100-900 mosm/ and after 12 hours of fluid restriction osmolarity should be more than 850 mosm/l

ADH help to concentrate the urine by shifting the fluid in the medullary cortex of the kidney.

If osmolarity is less than 100 mosm/l mean that antidiuretic hormone secretion is inappropriate. That why astronauts able to produce concentrated urine.

Low level than the normal indicates the diabetes insipidus, renal tubule necrosis or severe pyelonephritis and aldosteronism.

Why did the space program reject it?

During space flight, fluid volume of the human gets effected. It leads to increase ADH which in turn causes reduce intake or hypovolemia to maintain homeostasis in the space, red mass cell changes and fluid shift between spaces these are immediate response of ADH,

Now the astronaut is already having problem with osmolarity, if space program permits his ADH hormone affect more and causes fluid imbalance in the body or in the severe case may lead to permanent kidney problem or failure and his life expectancy decease so space program rejects due to this reason

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