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Chapter 62- Renal and Urinary System
Anatomy and Physiology
• Kidney
o Enclosed in the renal capsule
o Renal cortex is the outer layer of the renal capsule; renal medulla is the inner region
o Nephrons; selectively secretes and reabsorbs ions and filtrates
The functional unit of the kidney
• Functions of kidneys o Maintain acid-base balance
o Excrete end products of body metabolism
o Secrete renin to regulate BP and erythropoietin to stimulate the bone marrow to produce
Rbcs
o Synthesize vitamin D for calcium absorption and regulation of the parathyroid hormones
o Urine production
As fluid flows through the tubules, water, electrolytes, and solutes are reabsorbed
and other solutes such as creatinine, hydrogen ions, and potassium are excreted
O Homeostasis of water
ADH responsible for reabsorption of water by kidneys
ADH secretion is stimulated by dehydration, high sodium intake, & decreased
blood volume
Water is drawn out of the tubules by osmosis and returns to the blood o
Homeostasis of sodium
When sodium increases, extra water is retained to preserve osmotic pressure
Increase in sodium and water increases blood volume and BP
Reabsorption of sodium in distal convoluted tubules is controlled by the
reninangiotensin system
O Homeostasis of potassium
Increases in the serum potassium level stimulate the secretion of aldosterone
Aldosterone stimulates the distal convoluted tubules to secrete potassium; this
action returns the serum potassium concentration to normal
O Homeostasis of acidity
Blood ph is controlled by maintaining the concentration of buffer systems
Carbonic acid and sodium bicarbonate form the most important buffers for
neutralizing acids in the plasma
O Adrenal glands
One on top of each kidney; Influence BP and sodium and water retention
Diagnostic Tests
• Determination of serum creatinine level o
Description
Measures the amount of creatinine in the serum
Creatinine is the end product of protein and muscle metabolism
O Analysis
Reflects glomerular filtration rate
Kidney disease is the only pathological condition that increases the serum
creatinine
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• Determination of blood urea nitrogen level (BUN)
o Description
Serum test that measures the amount of nitrogenous urea
o Analysis
Indicate the extent of renal clearance of urea nitrogenous waste products
• BUN/creatinine ratio o Elevated levels suggest
renal dysfunction
o Decreased BUN/creatinine ratio occurs with fluid volume deficit, obstructive uropathy,
catabolic state, and a high-protein diet
o An increased BUN/creatinine ratio occurs with fluid volume excess
• Urinalysis o Interventions
10-15 ml of first morning voiding
• A 24-hour urine collection o At the start time,
instruct the client to void and discard that sample;
collect all urine for the prescribed time (24 hours);
keep the urine specimen on ice or refrigerated and
check with the laboratory regarding adding a
preservative; at the end of the prescribed time,
instruct client to empty bladder and add urine the
collection container
• Specific gravity determination o Description
Urine test that measures ability of kidneys to concentrate urine o Interventions
Multiple dipstick method, refractometer, urinometer
Normal random reference interval is 1.005-1.030
An increase: occurs with insufficient fluid intake, decreased renal perfusion, or
increased ADH
A decrease in specific gravity: increased intake or DI; may also indicate renal
disease or the kidneys’ inability to concentrate urine
• Urine culture and sensitivity testing
o Description
Identifies the presence of
microorganisms o Interventions
Collect the midstream sample in a
sterile container; send to lab
• Creatinine clearance test o Description
Evaluates how well the kidneys remove creatinine from the blood, estimate of
GFR
Obtaining a blood sample and timed urine specimens
Creatinine clearance test provides the best estimate of the GFR; the normal GFR
is 125 ml/minute in a young adult, GFR is 65 ml/minute in age 65 plus
o Interventions
Encourage fluids before and during test, avoid caffeinated beverages
Ask client to void, and discard the first sample; keep urine specimen on ice or
refrigerated; at the end of the prescribed time, ask client to empty bladder and
add the final urine to collection container; send to lab
• KUB (Kidneys, ureters, and bladder) radiography o
An x-ray of urinary system to detect urinary calculi
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• Bladder ultrasonography (bladder scanning) o
Noninvasive method for measuring the volume of
urine in bladder
• Intravenous urography o Description
X-ray procedure in which IV injection of radiopaque dye is used to visualize and
identify abnormalities in the renal system
O Preprocedure interventions
Assess for allergies to iodine, seafood, radiopaque dyes; and contraindications
such as pregnancy, medical history of asthma, cardiac disease, renal
insufficiency
Inform the client about the possible throat irritation, flushing of the face, warmth,
or a salty metallic taste during the test
O Postprocedure interventions
Instruct client to drink at least 1L of fluid; monitor for allergic reaction to dye;
contrast dye is potentially damaging to kidneys, the risk is greater in older clients
and those experiencing dehydration
• Renography (Kidney scan) o Desription
An IV injection of a radioisotope for visual imaging of renal blood flow, GFR,
tubular function and excretion
O Preprocedure interventions
Informed consent; allergies; no dietary restrictions; remain motionless during test o
Postprocedure interventions
Encourage fluid intake; allergic reaction; radioisotope is eliminated in 24 hours
• Cystoscopy and biopsy of the bladder o
Description
The bladder mucosa is examined for inflammation, calculi, or tumors by means of a
cytoscope
O Preprocedure interventions
Informed consent; if biopsy is performed, withhold foods and fluids; if cystoscopy
alone, no special prep
O Postprocedure interventions
Increase fluid intake; monitor intake and output; encourage deep-breathing to relieve
bladder spasms; administer sitz bath for abdominal pain; inform the client that
burning on urination, pink-tinged or tea-coloured urine, and urinary frequency
are common and resolve in a few days; monitor for bright red urine or clots
• Renal biopsy o Description
Insertion of a needle into the kidney to obtain a sample of tissue for examination o
Preprocedure interventions
Baseline coagulation studies; informed consent; withhold fluids & foods o Intervention
during: position prone with pillow under abdomen and shoulders o Postprocedure interventions
Vital signs, especially for hypotension and tachycardia (bleeding); provide pressure to
biopsy site for 30 min; monitor hemoglobin and hematocrit; place client on strict bed rest in supine
position; encourage fluid intake of 1500-2000 ml; avoid heavy lifting and strenuous activity for 1-2
weeks
Acute Kidney Injury
• Description
o Rapid loss of kidney function from renal cell damage
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Chapter 62- Renal and Urinary System
Anatomy and Physiology
• Kidney
o Enclosed in the renal capsule
o Renal cortex is the outer layer of the renal capsule; renal medulla is the inner region
o Nephrons; selectively secretes and reabsorbs ions and filtrates
The functional unit of the kidney
• Functions of kidneys o Maintain acid-base balance
o Excrete end products of body metabolism
o Secrete renin to regulate BP and erythropoietin to stimulate the bone marrow to produce
Rbcs
o Synthesize vitamin D for calcium absorption and regulation of the parathyroid hormones
o Urine production
As fluid flows through the tubules, water, electrolytes, and solutes are reabsorbed
and other solutes such as creatinine, hydrogen ions, and potassium are excreted
O Homeostasis of water
ADH responsible for reabsorption of water by kidneys
ADH secretion is stimulated by dehydration, high sodium intake, & decreased
blood volume
Water is drawn out of the tubules by osmosis and returns to the blood o
Homeostasis of sodium
When sodium increases, extra water is retained to preserve osmotic pressure
Increase in sodium and water increases blood volume and BP
Reabsorption of sodium in distal convoluted tubules is controlled by the
reninangiotensin system
O Homeostasis of potassium
Increases in the serum potassium level stimulate the secretion of aldosterone
Aldosterone stimulates the distal convoluted tubules to secrete potassium; this
action returns the serum potassium concentration to normal
O Homeostasis of acidity
Blood ph is controlled by maintaining the concentration of buffer systems
Carbonic acid and sodium bicarbonate form the most important buffers for
neutralizing acids in the plasma
O Adrenal glands
One on top of each kidney; Influence BP and sodium and water retention
Diagnostic Tests
• Determination of serum creatinine level o
Description
Measures the amount of creatinine in the serum
Creatinine is the end product of protein and muscle metabolism
O Analysis
Reflects glomerular filtration rate
Kidney disease is the only pathological condition that increases the serum
creatinine
Downloaded by NELSON KIIRU ()
, lOMoARcPSD|26582732
• Determination of blood urea nitrogen level (BUN)
o Description
Serum test that measures the amount of nitrogenous urea
o Analysis
Indicate the extent of renal clearance of urea nitrogenous waste products
• BUN/creatinine ratio o Elevated levels suggest
renal dysfunction
o Decreased BUN/creatinine ratio occurs with fluid volume deficit, obstructive uropathy,
catabolic state, and a high-protein diet
o An increased BUN/creatinine ratio occurs with fluid volume excess
• Urinalysis o Interventions
10-15 ml of first morning voiding
• A 24-hour urine collection o At the start time,
instruct the client to void and discard that sample;
collect all urine for the prescribed time (24 hours);
keep the urine specimen on ice or refrigerated and
check with the laboratory regarding adding a
preservative; at the end of the prescribed time,
instruct client to empty bladder and add urine the
collection container
• Specific gravity determination o Description
Urine test that measures ability of kidneys to concentrate urine o Interventions
Multiple dipstick method, refractometer, urinometer
Normal random reference interval is 1.005-1.030
An increase: occurs with insufficient fluid intake, decreased renal perfusion, or
increased ADH
A decrease in specific gravity: increased intake or DI; may also indicate renal
disease or the kidneys’ inability to concentrate urine
• Urine culture and sensitivity testing
o Description
Identifies the presence of
microorganisms o Interventions
Collect the midstream sample in a
sterile container; send to lab
• Creatinine clearance test o Description
Evaluates how well the kidneys remove creatinine from the blood, estimate of
GFR
Obtaining a blood sample and timed urine specimens
Creatinine clearance test provides the best estimate of the GFR; the normal GFR
is 125 ml/minute in a young adult, GFR is 65 ml/minute in age 65 plus
o Interventions
Encourage fluids before and during test, avoid caffeinated beverages
Ask client to void, and discard the first sample; keep urine specimen on ice or
refrigerated; at the end of the prescribed time, ask client to empty bladder and
add the final urine to collection container; send to lab
• KUB (Kidneys, ureters, and bladder) radiography o
An x-ray of urinary system to detect urinary calculi
Downloaded by NELSON KIIRU ()
, lOMoARcPSD|26582732
• Bladder ultrasonography (bladder scanning) o
Noninvasive method for measuring the volume of
urine in bladder
• Intravenous urography o Description
X-ray procedure in which IV injection of radiopaque dye is used to visualize and
identify abnormalities in the renal system
O Preprocedure interventions
Assess for allergies to iodine, seafood, radiopaque dyes; and contraindications
such as pregnancy, medical history of asthma, cardiac disease, renal
insufficiency
Inform the client about the possible throat irritation, flushing of the face, warmth,
or a salty metallic taste during the test
O Postprocedure interventions
Instruct client to drink at least 1L of fluid; monitor for allergic reaction to dye;
contrast dye is potentially damaging to kidneys, the risk is greater in older clients
and those experiencing dehydration
• Renography (Kidney scan) o Desription
An IV injection of a radioisotope for visual imaging of renal blood flow, GFR,
tubular function and excretion
O Preprocedure interventions
Informed consent; allergies; no dietary restrictions; remain motionless during test o
Postprocedure interventions
Encourage fluid intake; allergic reaction; radioisotope is eliminated in 24 hours
• Cystoscopy and biopsy of the bladder o
Description
The bladder mucosa is examined for inflammation, calculi, or tumors by means of a
cytoscope
O Preprocedure interventions
Informed consent; if biopsy is performed, withhold foods and fluids; if cystoscopy
alone, no special prep
O Postprocedure interventions
Increase fluid intake; monitor intake and output; encourage deep-breathing to relieve
bladder spasms; administer sitz bath for abdominal pain; inform the client that
burning on urination, pink-tinged or tea-coloured urine, and urinary frequency
are common and resolve in a few days; monitor for bright red urine or clots
• Renal biopsy o Description
Insertion of a needle into the kidney to obtain a sample of tissue for examination o
Preprocedure interventions
Baseline coagulation studies; informed consent; withhold fluids & foods o Intervention
during: position prone with pillow under abdomen and shoulders o Postprocedure interventions
Vital signs, especially for hypotension and tachycardia (bleeding); provide pressure to
biopsy site for 30 min; monitor hemoglobin and hematocrit; place client on strict bed rest in supine
position; encourage fluid intake of 1500-2000 ml; avoid heavy lifting and strenuous activity for 1-2
weeks
Acute Kidney Injury
• Description
o Rapid loss of kidney function from renal cell damage
Downloaded by NELSON KIIRU ()
