THE URINARY SYSTEM
The urinary or excretory system functions to control the volume
and composition of the blood. It filters waste products from the
blood and expels them from the body in the form of urine.
The Kidneys
The kidneys are two bean shaped organs found just above the waist on either side of the
vertebral column. Blood passes through the kidneys and waste products and excess fluid is
taken from it. The cleaned blood then returns to the circulatory system.
Nephrons are the filtration units of the kidney. Each nephron contains a cluster of blood
capillaries called glomeruli (singular is glomerulus). This is where the blood is actually filtered.
The renal cortex is the outer area of the kidney, the middle is called renal medulla and the inner
section is called the renal pelvis.
Ureters
Once urine is filtered through the nephrons, it drains into the renal pelvis. From the renal pelvis,
urine is transported away from the kidneys is tubes called ureters. The ureters join the urinary
bladder.
Urinary Bladder
The urinary bladder is a hollow, muscular organ that stores urine. When urine is expelled from
the bladder it is called micturition, voiding or urination. The bladder can also be referred to as a
vesicle.
Urethra
The urethra is a small tube leading from the bladder to the exterior of the body. The female
urethra is about 4cm long while the male urethra is 20cm long.
Urine
Urine is composed of 95% water the rest is made up of waste products.
Root
Ren
Nephr
Pyel
Combining form
Ren/o
Nephr/o
Pyel/o
Ureter
Cyst
Vesic
Urethr
Ureter/o
Cyst/o
Vesic/o
Urethr/o
Urin
Urin/a, urin/o, urin/i
Ur
Lith
Ur/o, -uria
Lith/o
URINE
Meaning
Kidney
Kidney
Refers to the space inside the
kidney
Urinary canal
Bladder
Bladder
Tube through which urine
leaves the body from the
bladder
Urine, the excretory product of
the kidneys
Urine
Stone
1
Prefix/suffix
-ptosis
Hydr/o
Olig/o
Meaning
Falling/displacement
Water
Deficiency/few/little
Activity 1 Write the meaning of the following words;
1. renogram
2. nephrolithotomy
3. glomerulitis
4. pyelonephrosis
5. vesicocele
6. urethrostenosis
7. urinalysis
8. oliguria
9. dysuria
10. lithotripsy
Activity 2 Build words which mean;
1) Surgical fixation of a kidney
2) Condition of pain in a kidney
3) Surgical repair of the renal pelvis
4) x-ray picture of the renal pelvis
5) Instrument to view the bladder
6) Specialist who studies the urinary
tract
7) Abnormal urination at night
URINE
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Diseases and disorders of the urinary system
The urinary system has two major types of disorders that affect it. One is when the filtration of urine
from the blood is disturbed, the other is when the flow of urine either from the kidneys to the
bladder, or from the bladder to the outside of the body, becomes blocked.
If the filtration of blood does not take place, then the blood quickly becomes toxic. If the patient is
not treated they will die. This condition is commonly known as renal failure. Interventions to save
the patient can be artificial filtration of the blood by a process called dialysis; another approach may
be a kidney transplant. Renal failure is caused by damage to the kidneys, which can include
infections, trauma, cancer, or damage caused by toxic (poisonous) agents, such as certain drugs.
Blockages in the ureters, bladder and urethra can be caused by inflammation from infections,
cancers and tumours, and mineral deposits that form stones or calculi – these are known are
kidney stones or renal calculi, and sometimes they have to be surgically removed. If a blockage
occurs in the renal tract then the urine begins to build up. If the blockage is not removed, the urine
will quickly backup into the kidneys and cause damage.
Other disorders involve the composition of urine, the amount of urine that is passed from the body,
and the ability of the body to control the bladder.
Diseases and disorders include:
Disease
Anuria
Cystitis (cyst/o means bladder)
Dysuria
Haematuria
Nephritis
Nocturia
Proteinuria
Polyuria
Renal calculi
Urethritis
Urinary alkaliniser
Urinary Tract Infection (UTI)
Urinalysis
Definition
An inability to pass urine, or an absence of urine
Inflammation of the bladder
Painful or difficult urination
Blood in the urine
Inflammation of the kidney
Abnormal urination during the night
Above normal levels of protein in the urine, usually indicating
a urinary tract infection
Large amounts of urine, of frequent urination
A stone in the urinary tract
Inflammation of the urethra
A medication to reduce acid content of urine
A general term meaning an infection in the ureters, bladder
and/or urethra
A test to analysis the composition of the urine
Activity 3 Read the following paragraph and rewrite it using lay terms.
A 26 year old woman presented with a two day history of severe dysuria. She has been
passing small amounts of urine with increasing frequency. A urinalysis was performed
with the results showing moderate proteinuria and haematuria. There was no indication
of nephritis or kidney involvement on physical examination, and a diagnosis of cystitis
was made. The patient was prescribed a urinary alkaliniser and antibiotics.
URINE
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