Download Chapter 17 – Urinary System I. The Urinary System consists of 4

Chapter 17 – Urinary System
I.
The Urinary System consists of 4 organs:
1.
2.
3.
4.
Pg. 454
2 kidneys that filter
blood & form urine
2 ureters to transport
urine to bladder
1 urinary bladder to
store urine
1 urethra to convey
urine out of body
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3.
4.
II.
Kidneys – are reddish brown, bean-shaped organs
12 cm long & enclosed in a tough, fibrous capsule
A.
Kidney Structure
1.
A medial depression
leads to a hollow
renal sinus which
blood vessels, nerves,
lymphatic vessels, &
the ureter enter
2.
Inside the renal sinus lies a renal pelvis
– the widened, superior end of the ureter
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The renal pelvis is subdivided into smaller
tubes, called major & minor calyces
(1=calyx)
Small elevations called renal papillae project
into each minor calyx (pyramid apex)
5.
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Kidney Functions
1.
regulate volume, composition, & pH
of body fluids
2.
remove wastes from blood
3.
help control rate of RBC formation
4.
regulate blood pressure
C.
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Pg. 456
2 distinct regions are found within the kidney
a.
b.
B.
Pg. 455
D.
The renal cortex contains the
nephrons (the functional units of the
kidney) and is found towards the
outside of the kidney; it dips into the
medulla to form renal columns
Nephron Structure
1.
2.
Renal Blood Vessels
1.
The abdominal aorta
gives rise to renal
arteries leading to
nephrons in the
kidneys; renal veins
take away CO2
Pg. 455
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The renal medulla is
towards the inside of
the kidney, &
contains cone-shaped
renal pyramids
A kidney contains 1 million
nephrons, each of which
consists of a renal
corpuscle & a renal tubule
The renal corpuscle is the
filtering portion of the
nephron
 it is made up of …
 glomerulus: ball of
capillaries
 glomerular capsule:
receives the filtrate
1
3.
4.
Pg. 457
The renal tubule
leads away from the
glomerular capsule &
first becomes a highly
coiled proximal
convoluted tubule,
then leads to the
nephron loop, and
finally to the distal
convoluted tubule
Several distal
convoluted tubules
join to become a
collecting duct
III.
Ureters – muscular tubes
that transport urine from
kidneys to base of
urinary bladder
IV.
Urinary Bladder
A.
a hollow, muscular organ lying in the
pelvic cavity
B.
contains the trigone (the openings
of the 2 ureters and the urethra)
C.
neck of urinary bladder at urethra forms an
internal urethral sphincter (muscle)
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VI.
Pg. 468
V. Urethra – a muscular tube that conveys urine
from the urinary bladder to the outside of the
body
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B.
C.
Muscular peristaltic waves convey urine to
the urinary bladder
“The Urge to Go” – Micturition
1.
The bladder muscles contract &
stretch, triggering the micturition
reflex & an urge to urinate is
sensed
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter27/animation__micturition_reflex.html
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2.
When these contractions become
strong enough, the internal
urethral sphincter is forced open
3.
The external urethral sphincter,
composed of skeletal muscle, is
under conscious control
Urine Elimination
A.
Urine is formed in nephrons by the
glomerulus (in the glomerular capsule
within the renal corpuscle), passes
through the tubules, and into:
1.
collecting ducts
2.
renal papillae
3.
minor and major calyces
4.
out the renal pelvis
5.
ureters
6.
urinary bladder
7.
urethra
8.
exit body
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VII. Urine Composition
A.
~95% water
B.
Urea - byproduct of amino acid metabolism
C.
Uric acid – byproduct of nucleic acid metab
D.
Trace amounts of amino acids
E.
Variety of electrolytes
F.
Urine composition varies & reflects the
amounts of water & solutes that the kidneys
eliminate to maintain homeostasis
G.
Output is usually:
0.6 – 2.5 L/day -OR50-60 mL/hr
(<30 mL may indicate kidney failure)
H.
pH can range from 4.5 to 8.0, but avg is 6.0
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2
VIII. Urinary System Disorders & Diagnoses
A.
Bacteriuria
1.
2.
3.
abnormal presence of
bacteria and/or
pus in the urine
indicates a kidney
infection or urinary
tract infection (UTI)
antibiotics required to
get rid of it
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C.
B.
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D.
Diabetes
chemical diagnosis is:
1. glucosuria / glycosuria –
abnormal appearance of
glucose in urine
 due to insufficient insulin
(breaks down glucose)
from pancreas
physical diagnoses are:
2.
polyuria – excessive urine output
3.
polydipsia – great thirst
4.
polyphagia – increased appetite
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Kidney Stones
1.
solid “stones” form in kidneys due to
diet &/or dehydration
2.
causes SEVERE pain as stones pass
through the ureters
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3.
World Records
E.
 Largest stone was
3 pounds
 Highest number of
stones was from
a Canadian man:
Proteinuria
1.
albumin (protein) helps regulate water
concentration in blood and is
not normally found in urine
2.
indicates kidney malfunction or
kidney (renal ) failure
F.
Feb 1986 April 2003
he had 4,504 stones
(~22 stones/day)
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Gout
1.
abnormally high levels of uric acid
2.
uric acid crystals are deposited in
joints, causing inflammation & pain
 usual joints are in hands & feet
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Hematuria
1.
abnormal
presence of
blood in the
urine
2.
a symptom of
many illnesses
3