anp2lab5urinaryVVIMP

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Andrews University Biology DepartmentAnatomy and Physiology II

Spring 2008

Lab 5 The Urinary System

Name _________________________ TA Signature ____________________

File # ________

IntroductionUrine formation begins when glomerular filtrate enters the nephron tubules of the kidneys. Thecomposition and volume of the glomerular filtrate then changes as water and many solutes from thefiltrate are returned to the blood by reabsorbtion and as some additional waste products in the blood aresecreted into the filtrate. The body channels the final product, urine, out of the kidneys through theureters and stores it in the urinary bladder. Through the formation of urine from blood, the kidneys arethe primary organs involved in the maintenance of the homeostasis of blood composition and volume andthus the composition of extracellular fluids. Look over Chapter 23 The Urinary System pp. 896-919(Saladin 4th edition) prior to lab. Bring your textbook to lab!

Part I. Structures of the Urinary System

Learn the following structures: Figures 23.1, 23.4, and 23.8Kidney

renal capsulerenal cortexrenal medullarenal columnrenal pyramidrenal papillamajor calyx

minor calyxrenal pelvisrenal arteryrenal vein

Nephronrenal corpuscle

glomerulusglomerular capsule

afferent arterioleefferent arterioleproximal convoluted tubule (PCT)nephron loop (loop of Henle)

descending limb

ascending limbdistal convoluted tubule (DCT)collecting duct (CD)

ureterurinary bladderurethra

Exit Quiz Score____________/15 TA Signature___________________


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Part II. Urinalysis

BackgroundBody chemistry does not just depend on the volume and composition of the food we eat. Its alsoinfluenced by what the kidneys keep and do not keep by the processes of reabsorption and secretion.Urine contains a great deal of information about body function. The kidneys continuously form urine,reabsorbing glucose, amino acids, water, and salts from the filtrate of blood plasma. Factors such asdiet, physical activity, body metabolism, disease, time of day, and body position can influence the

chemical composition of urine.Analysis of the urine, orurinalysis, offers a means of determining thecomposition of the extracellular fluid (ECF) and the how the kidneys are functioning. During this part ofthe lab, you will conduct a series of tests on a urine sample. You will observe and determine bothphysical and chemical characteristics of the urine.

The urine amounts that you eliminate over a 24-hour period varies widely. These amounts depend onthe amount of fluid you consume and the rate of excretion through avenues other than the excretorysystem, such as through perspiration and solid waste formation. Urine volumes commonly range from 1to 2 L per 24 hours.

Procedure:1. Work in groups of two. Get a urinalysis strip, a plastic test tube, a paper cup, and paper towels. Use

the paper cup to collect a sample of urine.

2. Carefully pour enough of the urine into the test tube so that the all the pads on the urinalysis strip willbe completely covered when you dip it into the tube. Record the colorand appearance (seePhysical Examination below) of the sample on the Urinalysis Data Sheet on p. 5.

3. Hold the strip by the handle and dip it into the urine specimen. Make sure the pads are all completelycovered by the urine. Immediately remove the strip, holding it against the edge of the test tube so theexcess urine drips back into the tube.

4. Hold the strip over the paper towels while you wait for the pads to change color (approx. 1 min.).Compare the strip pads with the color chart on the urinalysis strip bottle and record your results onthe Data Sheet.

5. Discard the used strip in the biohazard bag at the front of the room.6. Use the charts below to determine the normality or abnormality of the test results and interpret the

results. (24 pts)


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Physical Examination The colorof urine varies widely from colorless to almost black due to normal metabolic functions,physical activity, ingested materials, or infections. It is usually amber or straw-colored. However, urineis usually darker in smaller volumes than in larger amounts. The normal yellow color is from a pigmentcalled urochrome, a product of hemoglobin breakdown.

The appearance of the urine refers to the clarity of the specimen. A sample can be clear, slightlycloudy, cloudy, or turbid. Urine normally is clear when eliminated but becomes cloudy on standing.

Cloudy or turbid urine is caused by crystals, white and red blood cells, epithelial cells, bacteria, lipids,mucous, yeast, and foreign substances.

COLOR NORMAL/ABNORMAL? POSSIBLE CAUSES

Colorless Normal Recent fluid intake; diuretic use

Pale yellow Normal

Dark yellow Normal Concentrated urine due to dehydrationCarrotsVitamin A, C, and Bs

Amber/Orange Normal or Abnormal Bilirubin due to bile duct blockageCarrotsVitamins A & C

Riboflavin

Yellow-green Normal or Abnormal Bilirubin oxidized to biliverdin

Green/Blue-green Normal or Abnormal Pseudomonas (bacterial) infectionChlorophyll-containing foods

Pink/Red Normal or Abnormal Red blood cells/hemoglobin tissue damageMyoglobin (oxygen-carrier in muscle tissue) muscle damage(large amounts can cause kidney failure)Beets, blackberries, rhubarb anthocyanins (pink pigment)

Brown/Black Abnormal Heavy bleedingHemoglobin oxidized to methemoglobinMyoglobin

APPEARANCE NORMAL/ABNORMAL? POSSIBLE CAUSESClear Normal

Levels of Turbidity:Slightly cloudyCloudyTurbid

Normal or Abnormal Sqamous epithelial cells, RBCs, or WBCs/cellular materialMucousFatsExcessive proteinCrystallization or precipitation of salts (i.e. phosphates orcarbonates, urates, calcium oxalate)Uric acid


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Physical/Chemical Examination with a Urinalysis Strip Note: Specific gravity is a physical property, but reflects the chemical composition of urine. Specificgravity is a ratio of the density of a solution (g/mL) to that of water. Values of urine are higher than thatof water because urine is only 95% water with various excreted solutes that increase its density. A1.5 L urine sample contains about 35 g of nitrogenous end products of metabolism and 25 g ofions/electrolytes. Urea is the most abundant nitrogenous waste product of metabolism, along with uricacid, ammonia, and creatinine. Excreted ions include ammonium, potassium, sodium, bicarbonate,phosphate, and sulfate. Glucose is normally excreted in trace amounts of less than 1 g/day.

TEST NORMAL ABNORMAL POSSIBLE CAUSES OF ABNORMAL RESULTS

Leukocytes Negative Any positive result - Urinary tract infection

Nitrite Negative Any positive result - Bacteria in the urine (i.e. gram-negative bacilli)- Urinary tract or kidney inflammation

pH 4.5 8.0 Acidic (below 4.5)

Alkaline (above 8.0)

- Diabetes- Diarrhea- Starvation- Urinary tract infection treatment- Respiratory or metabolic acidosis

- Excessive vomiting- Kidney failure- Defects in renal tubular secretion and reabsorption

of bicarbonate- Urinary tract infection- Respiratory or metabolic alkalosis

Protein 0-8mg/dl Above 8mg/dl - Kidney inflammation (can be from bacterialinfection)

- Glomerular damage- Lupus erythematosus- Long-term high blood pressure

Glucose Negative Any positive result - Diabetes mellitus (high blood glucose levels)- Impaired ability to reabsorb glucose (can be

caused by kidney disease - renal glycosuria)

Ketones Negative Any positive result - Uncontrolled diabetes- High insulin levels-

Starvation, fasting, anorexia, high-protein or lowcarbohydrate diets- Increased metabolism disorders (hyperthyroidism)- Fever, acute or severe illness, severe burns

Urobilinogen Less than1mg/dl

More than 1mg/dl - Liver disease/overburdening of the liver- Excessive RBC breakdown (i.e. from reabsoprion

of a large hematoma)

Bilirubin Negative Any positive result - Biliary obstruction (i.e. gallstones, tumors)- Trauma to liver or gall bladder

Blood/Hemoglobin

Negative Any positive result - Urinary tract infection/inflammation- Kidney or bladder stones- Trauma to the kidney or urinary tract or fractured

pelvis- Bladder or kidney cancer

SpecificGravity

1.002-1.028g/ml

Above 1.028g/ml

Below 1.002g/ml

-Dehydration (not enough fluid intake, diarrhea,vomiting, excessive sweating)

- Glucose in the urine

- Excessive fluid intake- Diabetes insipidus- Renal failure- Kidney infection (involving the nephrons)


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Urinalysis Data Sheet

Physical Examination

CONSTITUENT RESULTS INTERPRETATION

Color

Appearance

Physical/Chemical Examination with Urinalysis Strip

CONSTITUENT RESULTS INTERPRETATION(normal / abnormal & possible reason why)

Leukocytes

Nitrate

pH

Protein

Glucose

Ketones

Urobilinogen

Bilirubin

Blood/Hemoglobin

Specific Gravity


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Part III. Microscopic Examination of Urine SedimentMicroscopic examination of the urine sediment may reveal the presence of various cells, crystals,bacteria, and renal casts. The presence of large numbers ofcells such as erythrocytes, leukocytes, orepithelial cells in the urine is indicative of renal disease. Although a few crystals are present in normalurine, their presence in large numbers may suggest a tendency to form kidney stones, and a largenumber of uric acid crystals occur in gout. Renal casts are formed from cells and sticky protein withinthe renal tubules. They are cylindrical in shape, taking the form of the tubules in which they were cast.The sides are parallel and the ends are usually round. Although a small number of casts are found in

normal urine, an increase in cast numbers is one of the best indicators of renal disease, and can alsoindicate congestive heart failure or dehydration. Casts are relatively fragile and may dissolve, especiallyin alkaline or dilute urine. The casts may be noncellular, or they may be cellular and contain leukocytes,erythrocytes, or epithelial cells.

Procedure:Look at the websites and pictures of urine sediument on the lab labtops. Draw and label an example ofeach type of component (cells, crystals, bacteria, and renal casts). (4 pts)

Component type:

Component type:Component type:

Component type:

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