Name _________________________
Urinary System Lab
Biology
Background
Animals must rid their bodies of the waste products of metabolism. In humans,
the kidneys function to remove metabolic waste from the blood & produce urine. The
filtering of wastes takes place in the nephrons. Each kidney has about 1.25 million
nephrons.
Urine normally consists of water, salts, & nitrogenous wastes. The amount of
each of these substances found in urine depends on a person’s health, diet, & activity
level. From urine tests, doctors can learn a great deal about a person’s health. Kidney
malfunctions, urinary tract infections, liver disease, & diabetes are just some of the
problems that can be diagnosed using urinalysis. Urinalysis involves physical, chemical,
& visual examination. Characteristics of urine tested in medical laboratories include
color, volume, specific gravity, cloudiness, odor, pH, protein content, sugar content,
presence of blood cells, & presence of sediments.
In part I of this lab you will review parts of the urinary system. In part II you will
use urinalysis to diagnose medical problems of several hypothetical patients using
artificial urine.
Part I
Procedure
1. Blood is carried to each kidney by a large artery. Color the descending aorta &
renal arteries red on the appropriate diagram. Color the inferior vena cava &
renal veins blue.
2. Color the kidneys brown.
3. The artery divides into smaller arteries and then into a ball of capillaries called the
Glomerulus. Label the Glomuerulus on the appropriate diagram.
4. Everything that is small enough is forced out of the blood. Blood cells remain in
the capillaries. Water, salts, glucose, amino acids, & urea pass into a cuplike
structure called Bowman’s capsule. Label Bowman’s capsule.
5. The original capillary twists itself around the long tube called the Loop of Henle.
Label the Loop of Henle.
6. Most of the water, all of the glucose, all of the amino acids, and some of the salts
return to the blood. The filtered blood returns to the body. The remaining material
in the Loop of Henle travel to the collecting duct. Label the collecting duct.
7. Fluid in the collecting duct passes into the ureter on its way from the kidneys to
the bladder. Color the ureter yellow. Color the bladder orange.
8. Urine leaves the bladder through the urethra. Label the urethra.
Part II
Normal urine is transparent. Old samples of urine may turn cloudy due to the
presence of bacteria growing in the urine sample after its collection. Fresh urine
samples that are cloudy may be due to a urinary tract infection or may indicate the
presence of blood cells, pus, or fat.
The color of urine depends in part on its concentration. Pale, diluted urine may be
the result of drinking large volumes of fluids, but may also indicate diabetes. Dark,
concentrated urine may be the result of dehydration or fever. A smoky red to reddishbrown color indicates the presence of red blood cells in the urine. This indicates a
defect in the kidney since blood cells should remain in the blood. Vegetables & fruits,
as well as vitamins and drugs can alter the color of urine.
The normal odor of urine may be altered by several factors. A foul odor in fresh
urine can indicate the presence of bacteria which may indicate a urinary tract
infection. A fruit odor indicates the presence of ketone in the urine. Ketones are a
product of the metabolism of fats which can occur due to diabetes or starvation.
Sugar can sometimes be found in the urine after eating a meal rich in
carbohydrates & during times of extreme stress. However, a consistent finding of
sugar in the urine may be an indicator of diabetes.
Urine is usually slightly acid having a pH of about 6. The normal range however
may vary from 4.7-8.0. Several factors including food, dieting, stress, drugs,
breathing rate, & liquid intake can affect the pH of the urine.
Procedure
1. Gather 3 test tubes & label them:
 Control
 Patient 1
 Patient 2
2. Place your labeled test tubes in a test tube rack.
3. Place 10 ml of the control urine sample in the appropriate test tube.
4. Place 10 ml of the patient 1 urine sample in the appropriate test tube.
5. Place 10 ml of the patient 2 urine sample in the appropriate test tube.
6. Examine & record the color of each urine sample in the appropriate column of the
data table.
7. Examine & record the transparency/cloudiness of each urine sample in the
appropriate column of the data table.
8. Using the wafting technique demonstrated by your instructor, record a description
of the odor of each sample in the appropriate location in the data table.
9. Obtain 3 glucose test strips. Using a different test strip for each sample, dip the
end of the glucose test strip into the sample. Record the results in the appropriate
column of the data table.
10. Obtain 3 strips of pH paper. Using a different strip of pH paper for each sample,
dip the end of the pH paper into the sample.
11. Compare the resulting color to the pH range chart. Record the pH of each sample
in the appropriate column of the data table.
12. Using the information provided in the introduction to Part II, list some possible
diagnosis for patient 1 & patient 2 in the data table.
Characteristic
Color
Control
Patient 1
Transparent/cloudy
Odor
Sugar content
pH
Diagnosis
X
Questions
1. What are the two main functions of the kidneys?
2. What similarities in function do the liver & kidneys share?
3. What distinguishes the function of the liver & kidneys?
Patient 2
4. What is one indication of kidney failure that is observable in the urine?
5. What happens if one kidney stops working?
6. What would happen if both kidneys stopped working?
7. What is dialysis?
8. What is the difference between filtrate & urine?
9. What parts of the filtrate are reabsorbed back into the blood of the kidney?
10. What parts of the filtrate make up urine?
11. Why should a urine sample be fresh when tested?
12. What are two indicators that a person could have diabetes?
13. What are two indicators of extreme dieting that are observable in the urine?