Urinary System CHAPTER 15. 2 Urinary System Overview Functions of urinary system –Removes waste...

Urinary System

CHAPTER 15

2

Urinary System Overview

• Functions of urinary system– Removes waste products from blood– Produces and eliminates urine– Kidneys produce hormone Erythropoietin

(EPO)• Stimulates production of red blood cells within

bone marrow

– Kidneys produce enzyme Renin• Aids in raising blood pressure

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Structures of the Urinary System

• Kidneys– Reddish-brown, bean-shaped organs

located on either side of the vertebral column at back of upper abdominal cavity

– Cortex • Outer layer of kidney• Contains millions of microscopic units called

nephrons– Functional units of kidneys

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• Kidneys: Components of Nephron – Glomerulus

• Ball-shaped collection of very tiny, coiled, and intertwined capillaries

– Bowman’s capsule (renal capsule)• Double-walled cup surrounding the glomerulus

– Renal tubule• Proximal convoluted tubule• Loop of Henle• Distal convoluted tubule

– Peritubular capillaries


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• Kidneys – Medulla

• Inner layer of kidney• Consist of triangular tissues called renal pyramids-

loops and collecting tubules of nephron • Pyramids extend into a cuplike urine collection

cavity called minor calyx• Minor calyces merge to form major calyx• Major calyces merge to form renal pelvis


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• Ureters– Muscular tubes lined with mucous membrane– One leads from each kidney down to urinary

bladder– Urine is propelled from renal pelvis through

ureters by wavelike contractions known as peristalsis


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• Bladder– Hollow, muscular sac in pelvic cavity

• Between pubic symphysis and rectum in men• Between pubic symphysis and uterus and vagina

in women• Serves as a temporary reservoir for urine• Spherical shaped when full• Resembles inverted pyramid when empty


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• Urethra– Mucous membrane-lined tube that leads from

bladder to exterior of body• Urine exits bladder through urethra• External opening of urethra is the urinary meatus

– Female urethra carries only urine – Male urethra carries both urine and semen

during ejaculation


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Formation of Urine

• Formation of urine consists of three distinct processes: glomerular filtration, tubular reabsorption, and tubular secretion– Process begins as blood enters kidneys via

left and right renal arteries• Renal arteries branch out into smaller vessels

throughout kidney tissue, until these arterioles reach cortex of kidney

• Each arteriole leads to a glomerulus

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Formation of Urine• Glomerular filtration

– As blood passes through the glomeruli, blood pressure forces materials through glomerular walls into Bowman’s capsule

• Glomerular Filtrate = water, sugar, salts, and nitrogenous waste products such as urea, creatinine, and uric acid that filter out of blood through thin walls of glomeruli

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Formation of Urine• Tubular reabsorption

– As glomerular filtrate passes through renal tubules, water, sugar, and salts are returned to bloodstream through network of capillaries that surround them

• Tubular secretion– Materials are selectively transferred from

blood into the filtrate to be excreted in the urine

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Formation of Urine

• Urine– Urine consists of water and other materials

that were filtered or secreted into the tubules but not reabsorbed

• Normally one percent of glomerular filtrate is excreted as urine

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Characteristics of Normal Urine

• Color– From pale yellow to a deep golden color– Darker the urine, greater the concentration

• Clarity– Normal urine is clear– Cloudy, turbid appearance to the urine may

be due to presence of pus, bacteria, presence of bladder or kidney infection, or a specimen that has been standing for more than an hour

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• Odor– Normal urine is aromatic – Has a strong but agreeable odor

• Specific gravity– Normal urine has specific gravity of 1.003 –

1.030– Specific gravity = measurement of the amount

of solids in the urine

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• pH– Normal urine is slightly acid, pH of 6.0

• pH range is 4.5 – 8.0

– pH represents relative acidity or alkalinity of a solution

• pH of 7.0 is neutral• pH below 7.0 is acid• pH above 7.0 is alkaline (base)


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• Protein– Normal urine may have small amounts of

protein present– Only in insignificant amounts, too small to be

detected by reagent strip

• Glucose– Normal urine does not contain glucose


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• Ketones– Normal urine does not contain ketone

bodies– Ketones result from the breakdown of fats


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Common Signs and Symptoms

• Albuminuria– Presence in urine of abnormally large

quantities of protein, usually albumin– Also known as proteinuria

• Anuria– Cessation (stopping) of urine production, or a

urinary output of less than 100 ml per day

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• Bacteriuria– Presence of bacteria in urine

• Dysuria– Painful urination

• Enuresis– Condition of urinary incontinence,

especially at night in bed– Bedwetting


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• Fatigue– State of exhaustion or loss of strength or

endurance– May follow strenuous physical activity

• Frequency– In case of urinary frequency = urination at

short intervals (frequently) without increase in the daily volume of urinary output due to reduced bladder capacity


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• Glycosuria– Abnormal presence of sugar, especially

glucose, in urine

• Hematuria– Abnormal presence of blood in urine


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• Ketonuria– Presence of excessive amounts of ketone

bodies in urine

• Lethargy– State or quality of being indifferent, apathetic

(without emotion), or sluggish


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• Malaise– Vague feeling of bodily weakness or

discomfort, often marking the onset of disease of infection

• Nocturia– Urination, especially excessive, at night– Also called nycturia


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• Oliguria– Secretion of a diminished amount of urine

in relation to fluid intake– Scanty urine output

• Polydipsia– Excessive thirst


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• Polyuria– Excretion of abnormally large amounts of

urine

• Pyuria– Pus in urine, usually a sign of an infection

of urinary tract

• Urgency– Feeling to void urine immediately


PATHOLOGICAL CONDITIONS

Urinary System

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Cystitis

• Pronounced– (siss-TYE-tis)

• Defined– Inflammation of urinary bladder

• Characterized by urgency and frequency of urination, and by hematuria

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Glomerulonephritis (Acute)

• Pronounced– (gloh-mair-yoo-loh-neh-FRYE-tis)

• Defined– Inflammation of glomerulus of kidneys

• Condition characterized by proteinuria, hematuria, and decreased urine production

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Hydronephrosis

• Pronounced– (high-droh-neh-FROH-sis)

• Defined– Distension of pelvis and calyces of the kidney

caused by urine that cannot flow past an obstruction in a ureter

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Hydronephrosis

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• Pronounced– (neh-FROT-ic SIN-drohm)

• Defined– Clinical symptoms occurring when damage

to glomerulus of the kidney is present and large quantities of protein are lost through the glomerular membrane into urine

• Results in severe proteinuria• Also called nephrosis

Nephrotic Syndrome

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Polycystic Kidney Disease

• Pronounced– (pol-ee-SISS-tic kidney dih-ZEEZ)

• Defined– Hereditary disorder of kidneys in which

grapelike, fluid-filled sacs or cysts, replace normal kidney tissue

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Pyelonephritis (Acute)

• Pronounced– (pye-eh-loh-neh-FRY-tis)

• Defined– Bacterial infection of the renal pelvis of the

kidney• Infection begins in the bladder and travels up the

ureters to the renal pelvis

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Renal Calculi

• Pronounced– (REE-nal KAL-kew-lye)

• Defined– Stone formations in kidney

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Renal Cell Carcinoma

• Pronounced– (REE-nal SELL car-sin-OH-mah)

• Defined– Malignant tumor of kidney occurring in

adulthood• Patient is asymptomatic (symptom free) until latter

stages of disease

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Renal Failure, Chronic

• Pronounced– (REE-nal FAIL-yoor, KRON-ik)

• Defined– Progressively slow development of kidney

failure occurring over a period of years• Late stages of chronic renal failure known as end-

stage renal disease (ESRD)

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Vesicoureteral Reflux

• Pronounced– (vess-ih-koh-yoo-REE-ter-al REE-fluks)

• Defined– Abnormal backflow (reflux) of urine from the

bladder to the ureter

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Wilm’s Tumor

• Pronounced– (VILMZ TOO-mor)

• Defined– Malignant tumor of the kidney occurring

predominately in childhood• Most frequent finding is palpable mass in the

abdomen

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Treatment of Renal Failure

• Peritoneal Dialysis– Mechanical filtering process – Used to cleanse blood of waste products,

draw off excess fluids, and regulate body chemistry when kidneys fail to function properly

• Peritoneal membrane is used as filter

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• Continuous Ambulatory Peritoneal Dialysis (CAPD)– Requires transfer set, connected to bag of

dialysate solution– Dialysate solution remains in abdomen for

approximately four hours after exchange• Process is repeated 3 to 5 times daily

– Advantage: No machine, convenient for travel

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Continuous Ambulatory Peritoneal Dialysis


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• Continuous Cycling Peritoneal Dialysis (CCPD)– Uses a machine that warms the solution

and cycles it in and out of the peritoneal cavity at evenly spaced intervals at night while the patient sleeps

• Process takes 8 to10 hours• Last exchange remains in abdomen during the

day for approximately 12 to15 hours


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Continuous Cycling

Peritoneal

Dialysis

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• Hemodialysis– Process of removing excess fluids and toxins

from blood by continually shunting patient’s blood from body into a dialysis machine for filtering, and returning clean blood to patient’s bloodstream

• Usually three treatments a week, 3 – 4 hours at a time

• May be performed at dialysis center or at home


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Hemodialysis


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• Arteriovenous fistula– Access vessel created for use with

hemodialysis– Opening or fistula is created between an

artery and a vein in the forearm• Flow of arterial blood into venous system at point

of fistula causes vein to become distended• Provides a large enough vessel with a strong

blood flow for the hemodialysis connection


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Arteriovenous fistula for hemodialysis


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• Kidney transplantation– Surgical implantation of a healthy, human

donor kidney into the body of a patient with irreversible renal failure

• Kidney function is restored with a successful transplant and the patient is no longer dependent on dialysis

• Donor kidney may come from living donor (usually blood relatives) or cadaver donors (nonliving matches)


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• Kidney transplantation – Donor kidney surgically placed in iliac fossa– Donor renal artery connected to recipient’s

iliac artery– Donor renal vein connected to recipient’s

iliac vein– Donor ureter connected to recipient’s

bladder• Donor kidney usually functions once it is in place


DIAGNOSTIC TECHNIQUES, TREATMENTS

AND PROCEDURES

Urinary System

51

Diagnostic Techniques, Treatments, and Procedures

• Blood Urea Nitrogen (BUN)– Blood test performed to determine amount of

urea and nitrogen (waste products normally excreted by the kidney) present in blood

• Catheterization– Introduction of a catheter into a body cavity or

organ to instill a substance or remove a fluid

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• Creatinine clearance test– Diagnostic test for kidney function that

measures filtration rate of creatinine, a waste product (of muscle metabolism), which is normally removed by kidney

• Cystometrography– Examination performed to evaluate bladder

tone; measuring bladder pressure during filling and voiding


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• Cystoscopy– Process of viewing interior of bladder using a

cystoscope

• Extracorporeal lithotripsy– Non-invasive mechanical procedure for

breaking up renal calculi so they can pass through ureters

• Also known as extracorporeal shock-wave lithotripsy


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• Intravenous pyelogram– Radiographic procedure that provides

visualization of the entire urinary tract: kidneys, ureters, bladder, and urethra

• Contrast dye is injected intravenously• Multiple x-ray films are taken as medium is cleared

from blood

Diagnostic Techniques,Treatments, and Procedures

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• KUB (Kidneys, Ureters, Bladder)– X-ray of lower abdomen that defines size,

shape, and location of the kidneys, ureters, and bladder

• Contrast medium is not used with this x-ray

• Renal angiography– X-ray visualization of internal anatomy of

renal blood vessels after injection of a contrast medium


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• Renal scan– Radioactive isotope (tracer) is injected

intravenously– Radioactivity over each kidney is measured

as tracer passes through kidney


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• Retrograde Pyelogram (RP)– Radiographic procedure in which small-caliber

catheters are passed through a cystoscope into ureters to visualize ureters and renal pelvis


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• Ultrasonography– Procedure in which sound waves are

transmitted into body structures as a small transducer is passed over patient’s skin

– Also called ultrasound

• Urinalysis– Physical, chemical, or microscopic

examination of urine

Diagnostic Techniques, Treatments and Procedures

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• Urine culture– Procedure used to cultivate the growth of

bacteria present in a urine specimen, for proper microscopic identification of the specific pathogen

• Sample of urine specimen swabbed onto a culture medium plate and placed into an incubator for 24 to 72 hours

• Plate is then examined for growth on culture medium


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• 24-Hour urine specimen– Collection of urine excreted by the individual

over a 24-hour period• Urine collected in one large container• Also called a composite urine specimen

• Voiding cystourethrography– X-ray visualization of bladder and urethra

during voiding process after bladder has been filled with a contrast material


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Urine Specimen Collections

• Catheterized specimen– Also known as a sterile specimen– Using aseptic techniques, a very small,

straight catheter is inserted into the bladder via the urethra to withdraw a urine specimen

• Urine flows through catheter into a sterile specimen container

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• Clean-catch specimen– Also known as midstream specimen– Collection method used to avoid

contamination of the urine specimen from the microorganisms normally present on the external genitalia

• Patient cleanses external genitalia with antiseptic wipe

• Expels small amount of urine into toilet, then collects specimen in sterile container

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• First-voided specimen– Also known as an early-morning specimen– Patient instructed to collect first voided

specimen of the morning• Specimen should be refrigerated until it can be

taken to the medical office or laboratory


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• Random specimen– Urine specimen that is collected at any

time

• Residual urine specimen– Specimen obtained by catheterization after

the patient empties the bladder by voiding• Amount of urine remaining in the bladder after

voiding is noted as the residual amount


Urinary System CHAPTER 15. 2 Urinary System Overview Functions of urinary system –Removes waste...

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