Urinary System
Health Science Technology
Dr. Halbert
Urinary system = excretory system
 Removes some
wastes & excess
water and
maintains pH
balance
 Consists of 2
kidneys, 2 ureters,
bladder and
urethra
Kidney
 On either side of vertebral column
separated from the abdominal cavity
by peritoneum
 Enclosed in a mass of fatty tissue
called adipose capsule
 Also covered by tough fibrous tissue
called renal fascia or fibrous capsule
Kidney structure
 2 main sections
 Cortex
 Medulla
 Cortex: outer section,
contains most of the
nephrons
 Medulla: inner section,
contains most of the
collecting tubules, which
carry the urine from the
nephrons thru the kidney
Hilum
 Notched or
indented area
of the kidney
thru which
ureter, blood
vessels &
lymph vessels
enter & leave
kidney
Nephron
 Filtering unit of kidney
 One million nephrons
per kidney
 Consists of
 Glomerulus
 Bowman’s capsule
 Proximal convoluted
tubule
 Distal convoluted
tubule
 Collecting duct
Glomerulus
 First part of nephron
 Cluster of capillaries
 As blood passes thru from
renal artery, water,
mineral salts, sugar are
filtered out of blood
 RBCs & proteins are not
filtered out
 Filtered blood makes its
way to renal vein
Bowman’s capsule
 C-shaped structure
that surrounds the
glomerulus & is
start of convoluted
tubule
 Picks up filtered
material from
glomerulus &
passes them to
convoluted tubule
Passing through tubules
 Substances needed by body are
reabsorbed & returned to blood
capillaries
 Excess sugar, mineral salts; some
water; & wastes remain in tubule &
become urine
 Urine enters collecting ducts located
in medulla
Renal Pelvis
 Collecting ducts
empty into renal
pelvis, funnelshaped structure
which is first
section of ureter
Ureters
 Two muscular
tubes
 About 10-12 inches
 Peristalsis moves
urine through the
ureter to the
bladder
Bladder
 Hollow muscular
sac that lies behind
the symphysis
pubis & at midline
of pelvic cavity
 Mucous membrane
lining arranged in
folds, rugae which
disappear as
bladder expands
with urine
Bladder wall
 Formed by three layers of smooth
muscle
 Bladder stores urine until eliminated
 Urge to void occurs when bladder
contains 250 cc (1 cup) of urine but
bladder can hold much more
Sphincter
 Circular muscle controls opening of
bladder to prevent emptying
Urethra
 Tube that
carries urine
from the
bladder to the
outside
 External
opening is the
urinary
meatus
Urethra Male vs Female
 Female
 3.75 cm (1½ in)
 Carries only urine
 Opens in front of
vagina
 Male
 20 cm (8 in)
 Carries urine &
semen
 Passes through
prostate & out
through penis
Urine
 Liquid waste product
produced by urinary
system
 95% water
 Waste products: urea
(major waste product),
uric acid, creatinine,
mineral salts, pigments
 Urochrome: pigment
giving urine its yellow
color
 About 1½ to 2 quarts
produced daily from 150
quarts of liquid that is
filtered through the
kidney
Terms
Polyuria: excessive urination
Oliguria: decreased amounts of urine
Anuria: absence of urine
Hematuria: blood in urine
Pyuria: pus in urine
Nocturia: urination at night
Dysuria: difficult or painful urination
Retention: inability to empty the bladder
Incontinence: involuntary urination
Diseases of Urinary System
Cystitis
 Inflammation of
the bladder
 Usually caused by
pathogens entering
urinary meatus
 More common in
females
Glomerulonephritis
 Inflammation of the glomerulus
 Acute form: usually follows a
streptococcal infection
 Chronic form: progressive disease that
causes scarring of the glomeruli leads to
kidney failure
Pyelonephritis
 Inflammation of kidney tissue & renal
pelvis usually caused by bacteria
Renal calculus
 Kidney stone
 Calculus is formed
when salts in the
urine precipitate
 May become
lodged in renal
pelvis or ureter
Renal failure
 When kidneys stop functioning
 Acute renal failure (ARF): caused by
hemorrhage, shock, poisoning, injury,
dehydration
 Chronic renal failure (CRF): results from
progressive loss of kidney function,
caused by hypertension, toxins,
endocrine disease, chronic
glomerulonephritis
Uremia
 Toxic condition that occurs when
kidneys fail & waste products are
present in blood stream
Urethritis
 Inflammation of the urethra usually
caused by bacteria, viruses or
chemicals
Image Citations
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Slide 3: Anatomy of the urinary system, front view, 1/1/07,
http://www.health.uab.edu/default.aspx?pid=65499
Slide 5: Illustration of the anatomy of the kidney, 1/1/07,
http://www.uchospitals.edu/online-library/content=P01468
Slide 8: Glomerulus, 2/17/07,
http://www.aic.cuhk.edu.hk/web8/Hi%20res/Glomerulus.jp
g
Slide 13: Male Bladder & urethra, 2/17/07, http://www.ivyrose.co.uk/Topics/Urinary/Bladder_Urethra_Female_cIvyRo
se.jpg
Slide 18: Urine, 2/17/07,
http://www.open2.net/open2static/source/file/root/32/15/1
32078/urine.jpg
Slide 21: Cystitis, 2/17/07,
http://www.pathology.vcu.edu/education/renal/lab2.p.html