The Urinary SystemOrgans of the urinary system: Kidneys Ureters Urinary bladder UrethraKidney function - removes waste products from the blood stream and excess water Urinary bladder stores urine, and ureters, bladder and urethra make up the urinary tract 3
The Urinary SystemUrethra AortaKidneys LiverUrinary bladder Left UreterRight Ureter Prostate gland 4
Formation of UrineThree processes The nephron: of urine allows for formation: reabsorption of glomerular filtration water and tubular reabsorption electrolytes tubular secretion plays a vital role in maintaining normal fluid balance 5
Nephron- functional unit of the kidney where urine is formed. STAGES IN URINE FORMATION: 1.Filtration 2.Reabsorption 3.Secretion
SecretionNephron Reabsorption filtration Reabsorption of water
1. filtration -blood pressure forces small molecules from the glomerulus to the capsule Filtrates: glucose, amino acids uric acid, urea
2. Tubular Reabsorption -return of filtrates from blood at the proximal tubule through diffusion and active transport
3. Tubular Secretion -movement of molecules from blood into the distal convoluted tubule Molecules: drugs and toxins
Reabsorption of water -return of H20 via osmosis along the loop of Henle and collecting duct
Urinalysis • a physical and/or chemical examination of the urine. • It consists of a battery of chemical and microscopic tests to screen for: • urinary tract infections • renal disease, and disease • diseases of other organs that result in the appearance of abnormal metabolites (break-down products) in the urine.
Urinalysis • can reveal diseases that have gone unnoticed because they do not produce striking signs or symptoms. • Examples include diabetes mellitus, various forms of glomerulonephritis, and chronic urinary tract infections. • In other urinary diseases with symptoms, a urinalysis can help to confirm of rule out some diseases.
TESTS• Qualitative Tests for Normal Constituents • Urea Test • Uric Acid • Indican Test (Decompositon of Tryptophan)• Qualitative Tests for Pathological Constituents • Gunning’s Test (Ketone) • Benedicts Test (Glucose) • Exton’s Test (Albumin) • Smith’s Test (Bile pigments)
SPECIMEN COLLECTION • A "clean-catch" urine sample is performed by collecting the sample of urine in midstream. • Men or boys should wipe clean the head of the penis. • Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well. • A small amount of urine should initially fall into the toilet bowl before it is collected (this clears the urethra of contaminants). • Then, in a clean container (properly labeled with the name of the patient and date), catch about 1 to 2 ounces of urine and remove the container from the urine stream.
Specimens TypesVaries in method used and in time frame in which to collect specimenTypes of specimens: Random First morning Clean catch midstream Timed 24 hour 21
Specimens Types(cont.) Random – most common, taken anytime of day First morning – has a greater concentration of substances, taken in morning Clean catch midstream – genitalia is cleaned, urine is tested for microorganisms or presence of infection Timed – specific time of day, always discard first specimen before timing 24 hour – used for quantitative and qualitative analysis of substances 22
SPECIMEN COLLECTION • For an infant, thoroughly wash the area around the urethra. • Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on the genital area. • For males, the entire penis can be placed in the bag and the adhesive attached to the skin. • For females, the bag is placed over the labia majora. Place a diaper, check the infant frequently and remove the bag after the infant has urinated into it. • The urine is then drained into a labeled container.
UrinalysisEvaluation of urine to obtain information about body health and diseaseThree types of testing: Physical Chemical Microscopic 24
Physical Examination ofUrineVisual examination of physical characteristics Color and turbidity Volume Odor Specific gravity The refractometer or a reagent strip is used to measure specific gravity Refractometer Reagent Strips 25
MACROSCOPIC URINALYSIS • Clearing of the specimen after addition of a small amount of acid indicates that precipitation of salts is the probable cause of turbidity. • A red or red-brown (abnormal) color could be from a food dye, eating fresh beets, a drug, or the presence of either hemoglobin or myoglobin. • If the sample contained many red blood cells, it would be cloudy as well as red.
MACROSCOPICURINALYSIS • The first part of a urinalysis is direct visual observation. Normal, fresh urine is pale to dark yellow or amber in color and clear. • Normal urine volume is 750 to 2000 ml/24hr. • Turbidity or cloudiness may be caused by excessive cellular material or protein in the urine or may develop from crystallization or precipitation of salts upon standing at room temperature or in the refrigerator.
Normal Values of Urine Normal values of various elements have been established Average adult daily urine output is 1250 mL/24 hours Intake and output should be approximately the same 28
Examples of appearances of urinea red, cloudy appearance red but clear yellow, but cloudy
• The glomerular filtrate of blood plasma is usually acidified by renalpH tubules and collecting ducts from a pH of 7.4 to about 6 in the final urine. • However, depending on the acid- base status, urinary pH may range from as low as 4.5 to as high as 8.0. 8.0 • The change to the acid side of 7.4 is accomplished in the distal convoluted tubule and the collecting duct.
• (which is directly proportional to urine osmolality which measuresSpecific solute concentration) measures urine density, or the ability of thegravity kidney to concentrate or dilute the urine over that of plasma. • Specific gravity between 1.002 and 1.035 on a random sample should be considered normal if kidney function is normal. • Since the sp gr of the glomerular filtrate in Bowmans space ranges from 1.007 to 1.010, any measurement below this 1.010 range indicates hydration and any measurement above it indicates relative dehydration. dehydration
Specific Gravity (sp gr) • If sp gr is not > 1.022 after a 12 hour period without food or water • renal concentrating ability is impaired • In end-stage renal disease, sp gr tends to become 1.007 to 1.010. • Any urine having a specific gravity over 1.035 is • either contaminated, • contains very high levels of glucose
Apply Your KnowledgeWhat is the specific gravity shown on thisrefractometer screen? 34
-Apply Your Knowledge AnswerWhat is the specific gravity shown onthis refractometer screen? The specific gravity shown here is 1.030 35
Chemicals Found inUrine Ketone bodies – may indicate that patient is following a low carbohydrate diet or that patient has conditions such as starvation pH – provides information about metabolic status, diet, medication or several conditions Blood (hematuria) – may indicate patient is menstruating, have urinary tract infection or trauma 36
Chemicals Found inUrine (cont.) Bilirubin or urobilinogen – first signs of liver disease Glucose – common in patients with diabetes Protein – usually indicates renal disease Nitrite – suggests bacterial infection Leukocytes – urinary or renal infection Phenylketones – indicates PKU 37
Microscopic Examinationof Urine Microscopic examination used to view elements not visible without microscope Centrifuge spins urine to cause heavier substances to settle to the bottom • Cells • Casts • Crystals • Yeasts • Parasites • Bacteria 38
Glucose test • Benedict’s test • Aqueous glucose is mixed with Benedicts reagent, a solution of copper sulfate, sodium hydroxide, and tartaric acid. • The mixture is heated. • Carbohydrates which react with Benedicts reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide are classified as reducing sugars.
Results of Benedicts Test with Glucose,Sucrose, and Fructose
Glucose• Less than 0.1% of glucose normally filtered by the glomerulus appears in urine (< 130 mg/24 hr).• Glycosuria (excess sugar in urine) diabetes generally means mellitus.
• Exton’s Test • There are several acidsProtein which can be used to precipitate proteins - sulfosalicylic, trichloroacetic, nitric, and acetic acids. • Sulfosalicylic acid (SSA) is the most frequently used acid test because it does not require the use of heat. • Exton’s reagent is 5% sulfosalicylic acid in a
To perform the SSA procedure mix equal parts of patient urine and the reagent. Rate theamount of turbidity according to the following scale:
Interpretation • In rough terms, trace positive results (which represent a slightly hazy appearance in urine) are equivalent to 10 mg/100 ml or about 150 mg/24 hours (the upper limit of normal). • 1+ corresponds to about 200-500 mg/24 hours • a 2+ to 0.5-1.5 gm/24 hours • a 3+ to 2-5 gm/24 hours • a 4+ represents 7 gm/24 hours or greater.
• Normally, only small plasmaInterpretation proteins filtered at the glomerulus are reabsorbed by the renal tubule. • Normal total protein excretion does not usually exceed 150 mg/24 hours or 10 mg/100 ml in any single specimen. • More than 150 mg/day is defined as proteinuria. • Proteinuria > 3.5 gm/24 hours is severe and known as nephrotic syndrome.
Apply Your Knowledge A urine analysis has detected that a patient has protein in his urine. Why is this important? 46
-Apply Your Knowledge AnswerA urine analysis has detected that apatient has protein in his urine. Whyis this important?Protein in the urine usually indicatesrenal disease 47
KetonesGunning’s Test• Ketones (acetone, aceotacetic acid, beta- hydroxybutyric acid) resulting from either diabetic ketosis or some other form of calorie deprivation (starvation)• Shows positive test for:acetaldehyde and methyl ketones
KetonesGunning’s Test• Detection of COOH group is possible through its transformation to an ester in reaction with alcohol.• The esters have characteristic smell of flowers or fruits• It should appear the yellow precipitate of iodoform with characteristic smell• Ketones Normal:There are no ketones in your blood or urine.• Abnormal:Ketones are present in your blood or urine.
• . Indications of a positive test: The formation of a yellow precipitate or suspension of iodoform is a positive test a negative test (left) and a positive test (right)
emerald green at the point of contact between urine sampleand alcoholic iodine mixture Bilirubin – green Bilicyanine – blue Choletelin - yellow
• Smith’s Test should be conducted to determine whether bilirubin is present in the urine (i.e., bilirubinuria).• Urobilinogen is formed by intestinal bacteria from the breakdown of conjugated bilirubin, and it is usually excreted in feces.• However a small amount may be reabsorbed and excreted in urine.
• A positive test response indicates normal enterohepatic circulation of biliary pigments. High concentrations of biliary pigments may occur in hemolytic crisis, or cases of hepatic or intestinal dysfunction.