Shortcut Methods and Tricks to Solve Numericals on Excretory Products and Their Elimination

1. Filtration rate in kidneys:

• GFR = (plasma creatinine mg/dL * urine volume mL/min)/urine creatinine mg/mL.
• Remember the average urine output is 1-2 L, which is approximately 1000 to 2000 mL/minute.
• If the GFR value obtained is too high, check the units of urine volume.

2. Urine output:

• An adult passes out approximately 1L to 1.5L, which roughly translates to 15 to 25 mL/minute.
• If the urine output of an individual is very high or low, consider the possibility of diabetes insipidus or any kidney problem.

3. Urea concentration:

• The normal range is between 10-20mg/dL.
• If the level of urea is abnormally high, a person may have kidney diseases, dehydration, or excessive protein consumption.

4. Creatinine concentration:

• For men: 0.8-1.2 mg/dL.
• For women: 0.6-1.0 mg/dL.
• A high level of creatinine can be an indication of kidney disease or muscle damage.

5. Sodium and potassium concentration:

• Normal range for Sodium: 135-145 mEq/L
• Normal range for potassium: 3.5-5.0 mEq/L.
• If the values of sodium and potassium vary significantly from the ranges, look into the patient’s diet and medical history to pinpoint any underlying health conditions.

6. pH of urine:

• The normal range for the pH of urine is 4.5 to 8.0.
• If the urine pH is abnormally high or low, consider the individual’s diet, medications, and kidney function.

7. Specific gravity of urine:

• The normal specific gravity range is 1.002 to 1.030.
• If the specific gravity of urine deviates significantly from this range, it could indicate issues like diabetes insipidus or other kidney dysfunctions.

8. Clearance calculations:

• Remember the standard formula: Clearance = Urine Concentration * Urine Flow Rate / Plasma Concentration
• For creatinine clearance, the plasma concentration is usually measured in mg/dL, while the urine concentration is in mg/mL, and urine flow rate is in mL/min.

9. Osmolality of urine:

• The normal urine osmolality range is 500-1200 mOsm/kg.
• Dehydration can elevate urine osmolality, while certain medications or excessive water consumption can lower it.

10. Kidney stones:

• If the size of a kidney stone is not given in the question, assume it to be around 2-3 mm, which is a common size range for kidney stones.
• Be aware of any symptoms or complications related to the size of kidney stones, such as potential pain or obstruction of urine flow.

These shortcut methods and tricks can help you efficiently solve numericals on excretory products and their elimination in your JEE and CBSE board exams. Remember to thoroughly understand the concepts behind these numerical values and their significance in the field of human physiology for a comprehensive approach to solving these questions.