Question

Which one of the following components of urine in a healthy human does not differ much in concentration from that of blood plasma?
A. $N{H_4}^ +$
B. ${K^ + }$
C. $N{a^ + }$
D. $S{O_4}^{2 - }$

Answer 1

For a normal person urine consists of water, urea, salts and pigments. Abnormal components in the urine are glucose, protein, and acetone. Urea, uric acid, creatinine, urobilinogen, hippuric acid are the organic constituents. Hypobromite is decomposed to give nitrogen and urea is converted into ammonium carbonate. Urine contains $90\%$ and above of water. Ions are classified as intracellular and extracellular.

Complete answer:
Option A $N{H_4}^ +$: $N{H_4}^ +$ ions are very harmful to the human body. But it is found in the bounded form. So, the availability of this ion is less in blood plasma. This type waste and nitrogenous wastes are removed from the body by the urine. The value in the urine is about $90\%$ or two thirds in the urine.
Option B ${K^ + }$: ${K^ + }$ ions are used to maintain the normal pH value in the urine. It is the intracellular ion. So, it is less in the blood plasma. $25$ to $125$ milli equivalents per liter are the normal value of potassium ion in the urine of a normal person. It is crucial to the physiology of cell membranes. It is an important electrolyte in the human body.
Option C $N{a^ + }$: $N{a^ + }$ is the sodium ion that is mostly available in the water and it is also the extracellular ion. So, the level of this ion is similar in both blood plasma and urine. The normal value of sodium in the urine is $20\dfrac{{mEq}}{L}$. It is important for both body and muscles to work normally. Sodium is found mostly in lymph fluid and blood.
Option D $S{O_4}^{2 - }$: $S{O_4}^{2 - }$ ion is present in amino acids of the body. It is released only at the ill time of the patient. Creatinine and some other metabolic end products are not reabsorbed and excreted in normal condition also. So, the level of this ion is not much more than that of blood plasma.

Hence, Option D is the correct answer.

Note:
Importance of reabsorption is to remove toxic waste from the blood plasma. Reabsorption is the process of movement of water from the plasma. It is used to get the water and nutrients from the waste liquid called urine to the bloodstream. Glomerulus is used to filter the water and act as a filter. After the filtering the waste also contains important substances like ions and water. So further it will be reabsorbed by the tubular kidney. Glucose is not found in the urine because all of the glucose is reabsorbed at the tubular kidney to the bloodstream.