Lab 10

Approximate Time: 3 hours

Obtain the following items from your lab instructor:

• Red cup (to collect urine)
• Clear cup (to drink water)
• Plastic test tube (to bring urine sample to class)
• Graduated cylinder (to measure the volume of voided)

1. To begin, students must take the red cup, plastic test tube, and graduated cylinder and go to the restroom. Collect your urine in the cup.  Keep track of the volume voided – read the volume of urine collected in ml (using the graduated cylinder)
2. Pour about 13 ml of urine into the test tube.  Once those steps are finished, you can discard the urine left (from red cup) in the toilet and bring back to class the test tube containing your urine sample and the empty red cup. Record the color, odor, and transparency of your sample.
3. Using the urine strip and the color chart available in your table, place the test stick inside the test tube containing your urine sample. Blot excess urine from the stick with a paper towel.  Critically time and take note of the color of each test area – compare them to the color chart you were given.  When you are done, dispose the urine strip in the biohazard waste container.  Do not forget to wash your hands when you finish!Analyze your urine measurements.

** Anything contaminated with urine (e.g. tissue, paper towel, etc.) must also be disposed of in a biohazard waste container.

What were your urinalysis measurements (from your urinalysis test strip)?

*** ANYONE WHO HAS RENAL DISEASE, DIABETES, OR HEART DISEASE SHOULD REFRAIN FROM PARTICIPATING AS A SUBJECT IN THIS LAB

Within each lab group, you will choose an individual for each of the following experimental treatments:

Participant 1: Drinks 200 mL of water

Participant 2: Drinks 500 mL of water

Participant 3: Drinks 500 mL of water and ingest 1/2 salt tablet

Participant 4: No water

STEP 1 – Using the volume measurement and pH obtained in Activity 1 from the first void, enter the collected data in your table at 0 minutes.

STEP 2 – At 30, 60, and 90 minutes each experiment group member will empty their bladder into their urine collector pan (red cup).  Consume the assigned beverage in under 10 minutes.  Set the timer to 30 minutes (Record volumes in Table 2)

Note: One member of each group will also keep track of their specific gravity at each interval.  This is done by using a disposable transfer pipette and placing a drop of urine on the glass platform of the refractometer.  Place the cover over the sample and hold it under the light as you look through the eyepiece.  Record the number indicated on the left side of the refractometer by the border of the shadow and light area seen in the meter.  Urine usually has a specific gravity between 1.010 and 1.025.

STEP 3 – Calculate the urine formation rates for each individual.  Urine formation rate can be calculated by dividing the urine volume by the time since the last voiding (e.g. 100 mL urine/ 30 minutes = 3.33 mL/min).