CHAPTER 15
Urinary System
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
2
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
3
Structures of the Urinary System
• 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
4
Structures of the Urinary System
• Kidneys
– Medulla
• Inner layer of kidney
• Consist of triangular tissues called renal pyramidsloops 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
5
Structures of the Urinary System
• 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
6
Structures of the Urinary System
• 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
7
Structures of the Urinary System
• 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
8
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
9
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
10
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
11
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
12
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
13
Characteristics of Normal Urine
• 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
14
Characteristics of Normal Urine
• 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)
15
Characteristics of Normal Urine
• 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
16
Characteristics of Normal Urine
• Ketones
– Normal urine does not contain ketone
bodies
– Ketones result from the breakdown of fats
17
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
18
Common Signs and Symptoms
• Bacteriuria
– Presence of bacteria in urine
• Dysuria
– Painful urination
• Enuresis
– Condition of urinary incontinence,
especially at night in bed
– Bedwetting
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Common Signs and Symptoms
• 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
20
Common Signs and Symptoms
• Glycosuria
– Abnormal presence of sugar, especially
glucose, in urine
• Hematuria
– Abnormal presence of blood in urine
21
Common Signs and Symptoms
• Ketonuria
– Presence of excessive amounts of ketone
bodies in urine
• Lethargy
– State or quality of being indifferent, apathetic
(without emotion), or sluggish
22
Common Signs and Symptoms
• 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
23
Common Signs and Symptoms
• Oliguria
– Secretion of a diminished amount of urine
in relation to fluid intake
– Scanty urine output
• Polydipsia
– Excessive thirst
24
Common Signs and Symptoms
• 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
25
PATHOLOGICAL CONDITIONS
Urinary System
Cystitis
• Pronounced
– (siss-TYE-tis)
• Defined
– Inflammation of urinary bladder
• Characterized by urgency and frequency of
urination, and by hematuria
27
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
28
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
29
Hydronephrosis
30
Nephrotic Syndrome
• 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
31
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
32
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
33
Renal Calculi
• Pronounced
– (REE-nal KAL-kew-lye)
• Defined
– Stone formations in kidney
34
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
35
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 endstage renal disease (ESRD)
36
Vesicoureteral Reflux
• Pronounced
– (vess-ih-koh-yoo-REE-ter-al REE-fluks)
• Defined
– Abnormal backflow (reflux) of urine from the
bladder to the ureter
37
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
39
Treatment of Renal Failure
• 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
40
Treatment of Renal Failure
Continuous Ambulatory
Peritoneal Dialysis
41
Treatment of Renal Failure
• 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
42
Treatment of Renal Failure
Continuous
Cycling
Peritoneal
Dialysis
43
Treatment of Renal Failure
• 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
44
Treatment of Renal Failure
Hemodialysis
45
Treatment of Renal Failure
• 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
46
Treatment of Renal Failure
Arteriovenous fistula for
hemodialysis
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Treatment of Renal Failure
• 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)
48
Treatment of Renal Failure
• 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
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DIAGNOSTIC
TECHNIQUES, TREATMENTS
AND PROCEDURES
Urinary System
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
51
Diagnostic Techniques,
Treatments, and Procedures
• 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
52
Diagnostic Techniques,
Treatments, and Procedures
• 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
53
Diagnostic Techniques,
Treatments, and Procedures
• 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
54
Diagnostic Techniques,
Treatments, and Procedures
• 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
55
Diagnostic Techniques,
Treatments, and Procedures
• Renal scan
– Radioactive isotope (tracer) is injected
intravenously
– Radioactivity over each kidney is measured
as tracer passes through kidney
56
Diagnostic Techniques,
Treatments, and Procedures
• Retrograde Pyelogram (RP)
– Radiographic procedure in which small-caliber
catheters are passed through a cystoscope
into ureters to visualize ureters and renal
pelvis
57
Diagnostic Techniques,
Treatments and Procedures
• 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
58
Diagnostic Techniques,
Treatments, and Procedures
• 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
59
Diagnostic Techniques,
Treatments, and Procedures
• 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
60
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
61
Urine Specimen Collections
• 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
62
Urine Specimen Collections
• 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
63
Urine Specimen Collections
• 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
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