URINARY SYSTEM ACTIVITY

Background

Besides regulating the relative amount of general solutes and water in the body, the excretory system regulates the H+ (and thus the pH) of the body. Hydrogen ions result from carbonic acid formation (from CO2), inorganic acids from nutrients, and organic acids from metabolism. The body deals with increases in hydrogen ion in three manners; chemical buffers, respiratory mechanisms, and renal mechanisms. The main chemical buffer system is the bicarbonate/carbonic acid system discussed in class. Increases in H+ drive the reaction to produce more carbon dioxide and water. Similarly, the respiratory system increases in rate and tidal volume when hydrogen ion concentrations increase. Finally, the kidneys influence H+ in three manners:

1. H+ excretion

plasma H+ increases -> tubular cells actively secrete H+

2. Bicarbonate excretion

plasma H+ increases -> reabsorption of filtered HCO3-

3. Ammonia secretion

urine H+ increases -> NH3 secretion increases forming NH4+

In one of the following series of lab activities this information may be beneficial. Otherwise, have fun peeing!

Objective

1. You should be familiar with some of the diagnostic tests that are normally conducted on urine samples.

2. You should be familiar with the action of caffeine as a diuretic and how this chemical causes an increase in urine output.

3. You should be familiar with the various manners in which your body regulates pH and how problems with your respiratory and/or excretory system can lead to acidosis or alkalosis.

Materials

multi purpose urine test strips

disposable cup

beaker with 50 ml graduations

permanent marker

Procedure

Urine Analysis

1. As an individual acquire a single “Multi Purpose Urine Test Strip” and a disposable cup.

2. Proceed to the restroom and collect a clean catch urine sample (a sample taken during middle of your urination) in a disposable cup.

3. Dip the test strip into the urine sample for 1 to 2 seconds, note the color of the urine in the table provided, dispose of the urine sample and cup, wash your hands, and then return to the classroom to compare your test strip with the color strip on the vial containing the test strips.

4. You must wait ten seconds before comparing the test strip pH with the color strip on the test strip vial, and 1 minute must transpire before the urine ketones, proteins, and glucose levels can be determined. After making the comparisons record your values in the table provided.

5. After determining your values, use the internet to determine normal results for each of the test that you conducted. Furthermore, determine why the test is performed and what physiological systemic problems abnormal values help to diagnose and record this information in the appropriate place in question 1.

6. Use the internet to determine two other common diagnostic tests of urine samples. Identify each and describe their importance in question 2.

Diuretic Lab

1. For those so inclined, acquire a disposable cup, a beaker with 50 ml graduations, and a permanent marker.

2. Fill the beaker to its 50 ml with water and pour that water into the disposable cup, and mark and label the water level using the marker. Do this repeatedly until you have marked graduations for most of the cups’ volume (you wouldn’t want it to get too full later and spill).

3. Next, after making sure that your bladder is empty, acquire a clean glass, and prepare and drink two full glasses of pop labeled “A” or “B”. Afterwards, drink one full glass every 30 minutes.

4. Similarly, on the half-hour, return to the restroom with your handmade measuring cup, force urination, and measure and dispose of your fluid waste. Wash the cup out and wash your hands in the restroom before returning to class. On your return, record your urine output in the table provided.

5. Share your data with your classmates and answer question 4.

Problems with pH

1. After you and two others have completed the above activity, form a group and acquire patient information from your teacher. This information will contain information on the patients’ respiration, blood and urine pH, and blood bicarbonate levels.

2. Using the patient information and the internet, determine which of the following conditions is consistent with the patients’ vital signs (respiratory acidosis, respiratory alkalosis, metabolic acidosis, metabolic alkalosis). Identify the condition in question 3.

3. Next, explain in detail how each of your patients’ vital signs are associated with the condition that you have identified in question 3 and NOT the other three possible conditions. Also, hypothesize how these conditions might affect respiratory rate and blood and urine pH.

4. Finally, be prepared to present this condition and your logic in diagnosing your patient to the rest of the class during the remainder of the hour or during class on Tuesday.

URINE SYSTEMS ACTIVITY

Name: ______

Data Table

Urine Analysis

Urine Test

/

Data

Color
pH
Ketones
Proteins
Glucose

Diuretic Laboratory

Pop Label / A B / A B / A B / A B / A B / A B
30 min
60 min
90 min

Questions

1. Urine Analysis

pH

Ketones

Proteins

Glucose

2. Identify and describe two other common diagnostic test performed on urine samples.

3. Calculate a measure of central tendency for each of the two pop types that were consumed. Using this data, identify which pop was the diuretic and hypothesize a mechanisms for how caffeine can act as a diuretic (sorry, you will not find anything in your book).

4. Patient Diagnosis: ______

Patient #1

Blood CO2 = high, Blood HCO3- is normal

Patient #2

Blood CO2 = low, Blood HCO3- is normal

Patient #3

Blood CO2 = normal, Blood HCO3- is low

Patient #4

Blood CO2 = normal, Blood HCO3- is high