The urinary system consists of the kidneys, ureters, bladder, and urethra, which work together to produce and excrete urine. The kidneys filter waste from the blood to produce urine, which travels through the ureters to the bladder. When full, the bladder empties through the urethra. Urine contains water and waste products like urea, salts, and other dissolved substances. Dysfunctions like incontinence, retention, infection, or changes in urine production can indicate underlying issues.

1. URINARY
ELIMINATION

3. Introduction
◦ The urinary system consists of organs that produce and excrete urine from the
body.
◦ Urine contains waste: mostly excess water, salts and nitrogen compounds.
◦ Primary organs are the kidneys
◦ Normal adult bladder can store up to 5 liters.
◦ Also responsible for regulating blood volume and blood pressure.
◦ Regulates electrolytes.

4. Organs of urinary system
◦ The components of the urinary
system include :
◦ the kidneys
◦ the ureters
◦ the urinary bladder
◦ the urethra.

5. Kidney
◦ The kidneys are bean-shaped organs located at
the back of the abdominal cavity.
◦ They lie on either side of the spinal column.
◦ This area is known as the flank area and is against
the muscles of the back.
◦ The external kidney has a notch at the concave
border known as the hilum.
◦ The hilum is the entrance for renal artery, veins,
nerves and lymphatic vessels.

6. Internal structure of kidney
◦ The cortex is the outer layer;
arteries, veins, convoluted tubes
and glomerular capsules
◦ The medulla is the inner layer;
renal pyramids

7. Nephron
◦ 1 million nephrons
◦ The functional unit of the kidney
◦ Remove waste products of
metabolism from the blood
plasma.
◦ Waste products are urea, uric acid,
creatinine, sodium, potassium
chloride and ketone bodies.

8. Urine Formation

9. Ureters, bladder and urethra
◦ Ureters -tubes that carry newly formed urine from the bladder to the kidneys.
◦ Bladder-muscular sac that serves as a reservoir for urine; bladder stretches to
accommodate urine.
◦ Urethra- tube extends from the bladder to the external opening of the urinary
system, the urinary meatus

10. Urine
◦ The formation of urine has 3 processes, filtration, reabsorption and tubular
secretion.
◦ Urine consists of 95% water and 5% solid substances.
◦ The need to urinate is usually felt at 300-350ml of urine in the bladder.
◦ Typically 1000-1500 mL is voided daily.

11. Physical Characteristics of Urine
◦ Odor
–Fresh urine is slightly aromatic –Standing urine develops an ammonia odor –
Some drugs and vegetables (asparagus) alter the usual odor
◦ pH
– Slightly acidic (pH 6) with a range of 4.5 to 8.0 – Diet can alter pH
◦ Specific gravity
– Ranges from 1.010 to 1.025 – Dependent on solute concentration

12. Chemical Characteristics of Urine
◦ Urine is 95% water and 5% solutes
◦ Nitrogenous wastes (organic solutes) include urea, ammonia, uric acid, and
creatinine
◦ Other normal solutes include: – Sodium, potassium, phosphate, and sulfate
ions – Calcium, magnesium, and bicarbonate ions
◦ NaCl is the most abundant inorganic salt in the urine.
◦ Urea is the chief organic solute.
◦ Abnormally high concentrations of any urinary constituents may indicate
pathology
◦ Disease states alter urine composition dramatically

13. Urination
◦ Micturation, voiding, and urination all refer to the process of emptying the
urinary bladder
◦ Stretch receptors- special sensory nerve endings in the bladder wall that is
stimulated when pressure is felt from the collection of urine
– Adult: 250-450mL of urine
– Children: 50-200mL of urine

14. Factors affecting urination
◦ Growth and development
◦ Psychosocial factors
◦ Fluid and food intake
◦ Medications
◦ Muscle tone and activity
◦ Pathologic conditions
◦ Surgical and diagnostic procedures

15. Altered urine production
◦ Polyuria- a.k.a. diuresis
– production of abnormally large amounts of urine by the kidneys
– 2500mL/day for adults
– Causes:
• Excessive fluid intake
• Intake of alcohol and caffeine
• Diabetes mellitus
• Hormone imbalances
• CKD
– Other signs associated with diuresis: polydipsia, dehydration and weight loss

16. ◦ Oliguria
- Voiding scant amounts of urine
- Less than 500mL/day
◦ Anuria
- Voiding less than 100mL/day
- May result from low fluid intake, kidney disease, severe heart failure, burns
and shock
- Usually accompanied by fever and heavy respiration

17. ◦ Frequency
- voiding at frequent intervals that is more often than usual.
- Total amount of urine voided may be normal but amount of each voiding
are small---50-100mL
- May result from increased fluid intake, cystitis, stress, or pressure on the
bladder
◦ Nocturia
- increased frequency at night that is not a result of an increased fluid intake
- Expressed in terms number of times the person gets out of bed to void

18. ◦ Urgency
-feeling that the person must void.
-Usually accompanies psychologic stress, and irritation of the urethra
-Common in young children who have poor external sphincter control

19. ◦ Dysuria
- voiding that is either painful or difficult
- May result from stricture of the urethra, urinary infections, injury to the
bladder and/ or the urethra.
- Described as a burning sensation during voiding
- Burning during micturation if often due to an irritated urethra. Burning
following urination may be a result of bladder infection
- Often associated with urinary hesitancy (delay and difficulty in initiating
voiding)

20. ◦ Enuresis
- repeated involuntary urination in children beyond the age when voluntary
bladder control in normally acquired (4-5yrs)

21. ◦ Urinary incontinence is considered a symptom, not a disease.
- Loss of bladder control
- Types:
• Functional incontinence- involuntary unpredictable passage of urine
• Reflex incontinence- involuntary loss of urine occurring at somewhat
predictable intervals when a specific bladder volume is reached.
• Stress incontinence- loss of urine of less than 50cc occurring with increased
intra-abdominal pressure

22. ◦ Total incontinence- continuous and unpredictable loss of urine.
◦ Urge incontinence- involuntary passage of urine occurring soon after a
strong sense of urgency to void.

23. ◦ urinary retention with overflow - dribbling incontinence that results when
the bladder is greatly distended with urine because of an obstruction
◦ Neurogenic bladder- describes any voiding problem related to neurologic
impairment or dysfunction.

24. ◦ Urinary retention- accumulation of urine in the bladder (as much as 3L) with
associated inability of the bladder to empty itself.
◦ Adult- can hold 250-450ml of urine in the bladder before micturation reflex in
triggered.
◦ Prolonged retention leads to stasis (slowing of the flow of urine) and
stagnation of urine which increases the possibility of UTI.
◦ Retention if distinguished from oliguria or anuria by the distention of the
bladder.
◦ Characterized by small, frequent voiding or absence of urine output