Question

Robert was diagnosed with hypertension at the age of 39. In taking better care of himself., Robert a former college athlete found himself eating poorly, consuming too much alcohol, smoking, and spending too much time sitting in front of the TV since graduating. His personal habits have also caused him to gain a significant amount of weight. Robert is now on two high blood pressure medications to try and control his blood pressure. He also modified his lifestyle to include regular exercise, stopping smoking and moderate alcohol consumption and a sodium diet.

Robert’s, father had died earl from renal failure due to hypertension he took his lifestyle changes seriously. Robert now 56, is a triathlon athlete and very competitive and strived to first in his age group. In order to gain the edge, he needs, he hired a certified clinical trainer, Carmen. Robert was experiencing dehydration and fatigue while exercising, so he wanted help to find a way to drink enough fluids while training.

Carmen designed a way for Robert to assess his physiological status (PS)before, during, and after his workouts. A urinalysis was done before, right after, and six hours after a two-hour training run to determine his renal status a measure of his PS.

The table below shows Robert’s urinalysis data.

Time	Color	Specific Gravity	Protein	Glucose	pH
Before	pale yellow	1.010	absent	absent	6.3
Immediately after	dark yellow	1.044	small amount	absent	4.4
Six hours post	yellow	1.032	absent	small amount	5.2

Questions

1. What does the color of Robert’s urine tell him about how concentrated or dilute it is? How does the urine color/concentration relate to the urine specific gravity at the same time?

2. The urine color and specific gravity can give Carmen information as to the hydration status of Robert’s body at three different times. What can she conclude from the information based on color and specific gravity?

3. Antidiuretic hormone (ADH) regulates the formation of concentrated or dilute urine. When is Robert releasing the greatest amount of ADH? Explain your answer.

4 Proteinuria (protein in the urine) after intense exercise is physiological (normal). However, protein is typically not present in urine. Why is that?

5. Trace glucose that was found in Robert’s urine six hours after his exercise, this concerned Carmen, however, Robert had a large meal an hour before the urinalysis. How could this affect the glucose in Robert’s urine?

6. Intense exercise can cause lactic acid to accumulate. How can Carmen tell Robert’s kidneys are trying to prevent acidosis? Describe this mechanism.

7. After reviewing Robert’s urinalysis data, do you think he should drink more water prior to starting his training to make sure he stays adequately hydrated? Explain your answer.

8. One of the medications the Robert takes to control his blood pressure is called an angiotensin converting enzyme inhibitor (ACE inhibitor), which inhibits the activation of angiotensin II. What are two of the mechanisms by which angiotensin II targets the kidneys to increase extracellular fluid volume, there are several?

Answer 1

1. The concentration of urine is proprotional to the intensity of colour of urine. Here, dark yellow urine is highly concentrated, yellow urine is moderately concentrated and pale yellow urine is least concentrated.

Similarly, urine concentration/colour is proportional to specific gravity. Highly concentrated dark yellow urine has highest specific gravity whereas least concentrated pale yellow urine has least specific gravity.

2. Based on colour and specific gravity, he can conclude that body is in great demand of water immediately after the workout, in moderate demand of water after six hours post and in least demand of water beore the workout. This is because water demand causes excess reabsorption of water from urine resulting in urine concentation.

3. Antidiuretic hormone (ADH) regulates the formation of concentrated or dilute urine by regulating water reabsorption from DCT and collecting duct. So, greater amount of ADH release result in higher water reabsorption and concenration of urine. Hence, we can say that ADH is released in excess amount immediately after exercise (highest urine concentration), in moderate amount after six hours post (moderate urine concentration) and in least amount before exercise (least urine concentration).

4. Protein is not normally present in the urine as they cannot filter through the glomerulus becuase of their larger molecular size.