1. Renal A&P and
Pathophysiology
Reference: Pathophysiology text by Kathryn McCance
Mindy Milton, PA-C, MPA

2. FUNCTIONS
 Homeostasis of the internal environment
 Maintain fluid and electrolyte balance
 Secretion of erythropoetin, renin, and
dihydroxy Vitamin D

3. Anatomy
 Paired organs found
within the retro-
peritoneal space
 Parts:
 Cortex
 Medulla
 Supporting connective
tissue
 Renal capsule: covers outer
surface
 Adipose capsule: adipose
tissue that surrounds
capsule
 Renal Fascia: dense fibrous
structure that anchors
kidney to surrounding
structures

4. Anatomy

5. ANATOMY
 NEPHRON
 Functional unit of the kidney
 Three types:
 Superficial cortical
 Midcortical
 Juxtamedullary nephrons - junction of cortex and medula,
loop goes deepest into the medulla -->urine concentration.
 Parts
 Glomerulus: filtration membrane
 Epithelial membrane:outer layer contain specialized cells called
podocytes important in filtration
 Basement membrane: middle layer
 Endothelial membrane: inner layer perforated by fenestrations

6. Anatomy
 Glomerulus
 Afferent arteriole: blood enters the glomerulus
 Efferent arteriole: blood leaves the glomerulus
 Blood pressure forces fluid out of the glomerulus into
the capsule
 Specialized cells known as juxtaglomerular cells
located around the afferent arteriole.
 Between the afferent and efferent arteriole is an area
of the distal tubule called the macula densa
 Forms the juxtaglomerular apparatus

7. Nephron

8. Anatomy: Glomerulus

9. Glomerulus

10. Glomerular Membrane: Podocytes

11. ANATOMY
 Nephron
 Parts
 Bowman’s capsule
 Proximal tubule
 Loop of Henle
 Distal convoluted tubule
 Collecting Duct
 Macula densa/
juxtaglomerular cells
(apparatus)
 Vasa Recta

12. Nephron

13. Blood Supply to the Kidney

14. ANATOMY
 BLOOD SUPPLY
 Vasa Recta
 Network of capillaries that descend around the
lower portion of the medullary loop of Henle
 Only blood supply to the medulla
 Influence osmolar concentration of the medullary
extracellular fluid necessary for a concentrate urine
 All capillaries drain into the venous system

15. Cortical Nephron

16. Medullary Nephron

17. Nephron blood vessels

18. Renal Blood Flow
 Glomerular arterioles
 Receives blood from interlobular arteries
 High pressure system
 Arterial side of the nephron
 Perfusion of 1200 ml per minute (20-25% of CO)
 Peritubular capillaries:
 Low pressure system
 Porous walls that allow for rapid reabsorption
 Differing structures for cortical and medullary nephrons
 Empties into the inferior vena cava

19. Autoregulation
 Mechanisms that maintain renal blood flow at
constant pressure between 80-180 mm Hg
 Afferent arterioles have intrinsic ability to control
glomerular blood flow and filtration rate
 GFR will stay relatively constant
 Changes in arteriolar pressure and afferent
arteriolar resistance occurs in the same direction
 Constancy of solute and water excretion

21. Autoregulation
 Example
 If systemic blood pressure increases, there will be
vasoconstriction of the afferent arteriole to maintain
filtration pressure
 If systemic blood pressure decreases, vasodilation of the
afferent arteriole to maintain filtration pressure
 Control mechanisms
 Myogenic response: Changes in stretch
 Decrease arterial pressure = afferent arteriole relaxes ￪
 Increase arteriolar pressure = afferent arteriole contracts ￬
 Tubuloglomerular feedback: macula densa recognize changes in
flow rate and NaCl levels
 Increased NaCl = ￬
 ￪

22. Control of Renal Blood Flow
 Neural Mechanisms
 Kidneys are innervated by the sympathetic nervous
system
 Stimulation of the sympathetic nervous system
 Decrease in systemic BP = arteriole vasoconstriction =
decrease in RBF and GFR
 local autoregulatory mechanisms dampen the response
 Hormonal Control
 Renin/angiotensin system
 Atrial Naturietic peptide: increased right atrial
pressure=decreased renin=decreased
aldosterone=decreased renal reabsorption of NA and
water=decreased blood volume

23. GLOMERULAR NET FILTRATION
 Pressures favoring  Pressures opposing
filtration filtration
 Glomerular capillary  Bowman’s capsule
hydrostatic pressure hydrostatic pressure
 Driving pressure that  Arterial end 10mmHg
supports GFR  Venous end 10 mmHg
 47mm Hg
 Glomerular capillary
 Bowman’s capsule colloid osmotic pressure
colloid osmotic pressure  Arterial end 25 mm Hg
 Venous end 35 mm Hg

24. Filtration Pressures

25. GLOMERULAR FILTRATION
 Filtration Pressure:
 Net pressure forcing fluid out of the glomerulus
 Factors that affect filtration
 Changes in hydrostatic pressure
 Changes in the diameter of the afferent or efferent
arterioles
 Large molecules like plasma proteins cannot move
through small pores in glomerular membrane
 Negative charge along the filtration membrane
impedes filtration of negatively charged particles as
they repel

26. Juxtaglomerular Apparatus
 Juxtaglomerular cells:
 Specialized cells located around the afferent
arteriole where it enters to renal corpuscle
 Macula densa:
 Portion of the distal tubule located between
the afferent and efferent arteriole.
 Functions:
 Control renal blood flow, GFR, and secretion
of renin

27. Reabsorption/Secretion
 Tubular reabsorption: movement of fluid
and solutes from the tubule to the
peritubular capillaries
 Active Transport
 Diffusion
 Tubular secretion: secretion of substances
from the peritubular capillaries to the
tubular lumen

28. The Regulation of GFR

29. PROXIMAL TUBULE
 FUNCTIONS:
 Reabsorption of electrolytes, water, and non
electrolytes such as amino acids, glucose, and
urea
 Acid base balance: reabsorption of Na
 Little actual change in osmotic balance
 Isotonic
 Secretes creatinine, drug end products

30. LOOP OF HENLE
 Function:
 Primary function is the establish a
hyperosmotic state within the medullary
interstitial fluid
 Occurs secondary to the reabsorption of more
solute than water into the medullary
interstitium
 Fluid in the descending limb increases solute
concentration
 Fluid leaving the ascending limb is more dilute
than when it entered

31. Nephron Functions

32. Loop of Henle Activity
Water NA/CL
Out of Out of
D Limb A Limb

33. COUNTER CURRENT
 Hyperosmolarity of the interstitial fluid of the
medullary of the kidney allows for the presence
of a concentration gradient that provides for
reabsorption of water in the presence of ADH
 Increased osmolarity of the loop and the vasa
recta deep in the medulla prevents washing out
of the medullary concentration gradient

34. Concentration of Urine

35. DISTAL TUBULE
 Final regulator of water balance
 Reabsorption of Na, H2O (ADH), HCO3
 Secretion of K, Urea, H, drugs

36. Functions of ADH

37. Functions of ADH

38. Overall Renal Function

39. Renal Hormones
 Vitamin D
 Diet and UV interaction of cholesterol in skin
 Activation of hydroxylation starts in the liver,
then KIDNEY
 PTH stimulates hydroxylation
 Vit D necessary for GI absorption and renal
tubule reabsorption of calcium and inorganic
phosphate

40. Renal Hormones (cont.)
 Erythropoietin
 Produced in KIDNEY and stimulates RBC
production in the bone marrow
 Decrease Oxygen to kidney -> increase Epo
 Afferent arteriole hypoxemia
 Renin
 Produced in KIDNEY and increases plasma
water and solute volume
 Hypovolemia; Hypotension; Low sodium, and
Beta 1 adrenergic stimulation -> increase
Renin

41. Anatomy: Ureters
 Muscular tubes that extend from kidney to bladder
 Lie retroperitoneal and attached to posterior abdominal
wall
 Enter posterior wall of urinary bladder
 Small slit like openings to prevent backflow of urine from
bladder to ureter
 Three layers
 Inner epithelial layer
 Middle muscular layer
 Outer connective tissue layer
 Peristaltic contractions move urine to bladder

42. Radiographic View of the Urinary
System

43. Anatomy: Urinary Bladder
 Hollow muscular organ that acts as storage
reservoir for urine
 Mucosa lining has rugae that disappear as
bladder distends
 Triangular area bounded by the ureteral
openings and the entrance to the urethra is
called the trigone
 Urethral entrance lies at the apex of the trigone
which is the most inferior aspect of the urinary
bladder
 Innervated by the post ganglionic fibers of the
parasympathetic nervous system

44. Anatomy of the Bladder

45. Micturition Reflex
 Stretch receptors are stimulated as the bladder
fills with urine
 Urge to urinate at approximately 200 ml of urine
 Relaxation of the external and internal
sphincters
 Gradual increase in volume will repetitively
stimulate the reflex until emptying of the bladder
occurs
 Infants do not have voluntary control over
urination because they do not have the
corticospinal connections established

46. Pathophysiology
 Finally …
 Renal
 Systemic disease
 Intrinsic
 Urinary
 Infection
 Obstruction

47. Obstructive Uropathy
 Consequences of obstruction
 Hydroureter: obstruction of the ureter with
accumulation of urine
 Hydronephrosis: retrograde increases in hydrostatic
pressure in the renal pelvis and calyces can increase
accumulation of urine in the renal collecting system.
 Complete obstruction: decreased glomerular filtration
and resulting renal failure
 Partial obstruction: chronically can cause
compression, accumulation of urine, ischemic damage
and atrophy with decreased concentrating ability of
the kidney.

48. Sites of Urinary Obstruction

49. Nephrolithiasis
 Kidney Stones: Nephrolithiasis
 Types:
 Calcium oxylate - alkaline urine
 Struvite - staghorn calcui.
 Uric acids - acidic urine.
 Pathophysiology:
 High urinary concentration of stone forming substances
 Changes in pH and temperature
 Drugs and diet
 Decreased urinary flow
 Grow in the renal papilla or pelvis

50. Nephrolithiasis
 Calcium stones
 Smallest
 Increased frequency in middle age men
 80% idiopathic
 Can be associated with increased levels of calcium
secondary to prolonged immobilization or
hyperparathyroidism
 Uric Acid
 Caused by gout with increased uric acid production,
and hyperuricosuria. Enhanced by concentrated and
acidic urine.

51. Nephrolithiasis
 Kidney Stones
 Clinical manifestations:
 Pain, Pain, Pain - can have radiating pain to labia/
scrotum, or disurea.
 Diagnostic
 BUN, Cr - is this stone causing a reduction in renal
function.
 KUB (Flat plate of the abdomen)
 CT scan
 IVP (Intravenous Pyelogram)

52. Lower urinary tract obstruction
 Prostate enlargement
 Urethral stricture
 Severe pelvic organ prolapse (cystocele)
 Neurogenic bladder dyssynergia

53. Neurogenic Bladder
 Dysfunctional filling or emptying
 Lower urinary tract symptoms
 Frequency, urgency, incomplete empty,
nocturia, incontinence, etc…
 Neurological lesions of brain, spinal cord
or peripheral system cause

54. Neurogenic bladder- causes

55. Renal Tumors
 Renal Tumors
 Renal adenomas: benign tumors located in renal
cortex
 Renal cell carcinoma: increased in men with 60%
survival rate at 5 years
 Risks
 Tobacco, Obesity, analgesic use
 Type: adenocarcinomas

56. Renal Cell Carcinoma
 Renal Cell Carcinoma
 Clinical Manifestations
 Hematuria
 Flank Pain
 Flank mass
 Fatigue
 Weight Loss
 Anemia
 Elevated alkaline phosphatase, LFT’S
 Diagnosis: renal ultrasound, CT scan, IVP, and renal
angiogram

57. Wilms Tumor
 Caused by genetic changes
 500 cases/yr in U.S.
 Age 1-5
 MOST COMMON solid tumor in children
 Diagnosed by parents noticing abd mass
 Treatment improved if Dx early
 DO your ABD Exam during WCC

58. Bladder Tumors
 Bladder Tumors
 Risks
 Tobacco
 Occupational exposure to chemical, rubber, textile
industries
 Know relationship to mutations in the tumor
suppressor p 53 gene
 Clinical manifestations
 Hematuria
 Progression associated with pelvic pain or
increased frequency of urination

59. Urinary Tract Infections
 UTI
 Risk Factors
 Age
 Sexually active females
 Pregnancies
 Antibiotic use
 Catheters
 Medical diseases: diabetes, neurogenic bladder

60. UTIs
 Cystitis
 Inflammation of the bladder
 Most common bacteria
 E Coli: outpatient
 Klebsiella Structural Changes
 Proteus Instrumentation
 Staphylococcus Nosocomial
 Clinical Manifestations
 Dysuria, frequency urgency, turbid urine
 Suprapubic discomfort, bleeding secondary to
involvement of superficial epithelial cells of
bladder

61. UTIs
 Pyelonephritis
 Pathology:
 Enlargement, scattered areas of abscess, increased
neutrophils in the tubules.
 Chronic infection: caliceal dilatation and cortical
scarring, interstitial edema, lymphocytic involvement,
increased casts in the tubular proper.
 Clinical Manifestations
 Fever, chills, flank pain, hematuria, generalized malaise
 Some research has shown that about 30% of patients
with lower tract manifestations have upper tract
disease as well.

62. UTIs
 Laboratory diagnosis:
 Urine
 Greater than 5-10 WBC’S
 Positive leukocyte esterase: enzymes found
primarily in neutrophilic granules.
 WBC casts: reflective of upper tract disease
 Markedly elevated protein suggestive of glomerular
disease not basic infection
 Hematuria or occult blood
 Urine culture with greater than 100,000 colonies of
individual bacteria

63. UTIs in Children
 Clinical Manifestations:
 Infants: fever, vomiting, diarrhea, jaundice
 Young children: can have dysuria, frequency,
bed wetting or incontinence in previously dry
child.
 Increased incidence of structural
abnormalities
 More rapid follow up for vesicoureteral reflux
to prevent renal scarring from chronic
pyelonephritis

64. UTIs in Children
 Vesicourethral Reflux
 Retrograde flow of infected urine into ureter
and kidney with perpetuation of infection and
resultant scarring of kidney cortex
 Increased presence in children
 Diagnosed by voiding cystourethrogram and
occasionally IVP.
 Structural changed evaluated by renal ultrasound
 Graded 1-5 See page 1412

65. Vesicoureteral Reflux

66. Glomerular Disorders
 Glomerulonephritis - nephritic
 Inflammation of the glomerulus
 Etiology:
 Immunologic mechanisms: post streptococcal
damage
 Drugs and toxins
 Vascular diseases
 Pathophysiology
 Glomerulus is the high pressure filtration
component of the normal kidney tubule
 Normally does not allow passage of large

67. Glomerular Injury Mechanisms

68. Glomerulonephritis
 Pathophysiology
 With damage to the glomerulus there is swelling,
increased permeability, and decreased effectiveness
of cell junctions
 Large proteins molecules and red blood cells are
filtered and are seen in the urine
 Swelling of the glomerulus will increase pressure,
decrease glomerular filtration, and can have a
secondary effect of causing systemic edema and
hypertension

69. Glomerulonephritis
 Clinical Manifestations:
 Hematuria
 Proteinuria exceeding 3-5 g/day
 Red blood cell casts
 HTN
 Edema
 Oliguria
 Smoky colored urine
 Generalized malaise, low grade fever, back pain

70. Glomerulonephritis
 Types
 Post streptococcal
 Can follow either pharyngitis or skin infections
 Clinical Manifestations usually occur within ten
days after pharyngitis and two to three weeks
after a skin infection
 Elevated anti-streptolysin O levels, history of
pharyngitis, hematuria, proteinuria, red blood cell
casts

71. Glomerulonephritis
 Types
 IgA nephropathy
 Occurs usually 24-48 hours after upper respiratory
or gastrointestinal infection
 Abnormal glycosylated IgA becomes trapped in the
glomerular membrane and increased proliferation
of the membrane secondary to the effect of
growth factors
 Initial manifestations is usually hematuria, with
decreased presentation with edema, proteinuria, or
HTN

72. Glomerulonephritis
 Types:
 RPGN (Goodpasture Syndrome)
 Antibody formation against both pulmonary
capillary and glomerular membranes
 Characterized by pulmonary hemorrhage and
rapidly progressing glomerular disease
 Rapid decline in glomerular function, HTN, edema,
renal insufficiency
 Most common young men 20-30 years of age

73. Nephrotic Syndrome
 Definition: excretion of 3.5 gm/day of protein
 Pathology:
 Excretion of large amount of protein leads to
hypoalbuminemia, decreased colloid osmotic
pressure, edema.
 Stimulation of adaptive responses secondary to third
spacing of fluids with elevated ADH, aldosterone, and
decreased responsiveness of the kidney to atrial
naturietic hormone. All lead to retention of sodium
and water.
 Hyperlipidemia secondary to increased synthesis by
the liver, decreased catabolism, and increased
delivery of lipid precursors to the liver

74. Nephrotic Syndrome
 Pathology (cont.)
 Normally 25-hydroxycholecalciferol is carried
attached to globulin, if lost in the urine there
will be decreased calcium absorption in the
gut with hypocalcemia
 Decreased calcium will cause secondary
hyperparathyroidism and osteomalacia

75. Nephrotic Syndrome

76. Renal Failure
 Acute renal failure (AKI)
 Oliguria of less than 30ml per hour or 400 ml/24
hours
 Types
 Pre-renal failure
 Intra-renal failure
 Post-renal failure

77. Renal Failure
 Pre-renal failure: (-) renal blood flow.
 Etiology: problem is outside of the kidney and
is related to decreased renal blood flow
 Hypotension, hypovolemia, inadequate cardiac
output (CHF).
 Trauma with blood loss; vomiting and
diarrhea with volume loss; dehydration
secondary to overuse of diuretics; third
spacing of fluid with relative volume depletion
that can occur in liver failure

78. Renal Failure
 Acute Renal Failure
 Pathology
 Decreased renal blood flow will decrease
glomerular filtration. Decreased urine output.
 Diagnostic criteria:
 Elevated specific gravity (kidney able to function
normally so it will try to conserve fluid in the presence of
decreased flow)
 Urine sodium less than 10mEq (kidney function normal
so it will conserve sodium in the presence of decreased
flow)
 BUN/Cr ratio is greater than 15:1 (BUN will elevate
greater than Cr due to decreased glomerular filtration
with normal tubular function

79. Renal Failure
 Acute renal failure
 Intra-renal failure
 Etiology:
 Acute tubular necrosis: nephrotoxic or ischemic
 Glomerulonephritis
 Vascular disease
 Intertstitial nephritis
 Acute Tubular Necrosis - most common.
 Nephrotoxic: drugs like aminoglycosides, heavy metal
poisoning, radiocontrast media.

80. Renal Failure
 Acute Renal Failure
 Acute Tubular Necrosis
 Ischemic etiology
 Most common post trauma, surgery, blood loss with
decreased renal blood flow and ischemic of the tubules.
 Patchy loss of function to tubules with decreased tubular
function
 Oliguria with urine output of less than 400 ml per 24
hours

81. Renal Failure
 Acute Tubular Necrosis
 Tubular obstruction: oliguria is partially caused by
ischemic edema, sloughing of tubular cells and
products of inflammation causing obstruction of
urine flow
 Changes in permeability with increased tubular
reabsorption
 Regional hypoxia may cause increase in the
release of angiotensin and decreased renal blood
flow

82. Renal Failure
 Acute Tubular Necrosis
 Diagnostic criteria
 Urine output less than 400 ml per 24 hours
 Specific gravity of urine is low (in this case even though
the kidney has a decreased flow pattern and the
normal adaptive response would be to retain water, the
kidney tubule is damaged and concentrating ability is
reduced)
 Urine sodium greater than 30mEq (again the kidney
tubule should be retaining sodium in the presence of
decreased flow, but the tubule is abnormal secondary
to the damage and continues to waste sodium.
 BUN/Cr ratio less than 15:1: Generally higher elevations
of serum Cr as the tubule normally secretes Cr;
abnormal function of the tubule means decreased
excretion

83. Renal Failure
 Acute renal failure
 Post renal acute renal failure
 The etiology is obstruction of urine flow outside of
the kidney proper
 Often can be caused by prostate enlargement,
bladder outlet obstruction
 Obstruction of urine flow will cause increasing
backup of urine flow and pressure within the
kidneys bilaterally, with anuria initially

84. Renal Failure
 Acute Renal Failure
 Clinical Manifestations
 Phases
 Oliguria:
 Less than 30 ml urine output per hour
 Associated elevation of BUN and CR
 Edema, CHF(Cardiac), N/V, fatigue, hyperkalemia, fluid
retention
 Diuretic phase
 Increased urine output with poor reabsorption in the
tubules can lead to decreased NA, K, dehydration
 Acute Tubular Necrosis
 Recovery phase
 Can lasts up to 6-12 months

85. (acute) Renal Failure

86. Oliguria Mechanisms in AKI

87. Chronic Renal Failure
 Chronic renal failure is the irreversible loss
of renal function that affects nearly all
organ systems
 Progression
 Reduced renal reserve
 Renal insufficiency
 Renal failure
 End-stage renal disease

88. Renal Failure
 Chronic Renal Failure
 Creatinine and Urea Clearance
 Creatinine is released from the muscle and
excreted by the kidney
 Excreted by glomerular filtration and secretion
 Amount produced equals amount excreted

89. Renal Failure
 Chronic Renal Failure
 Creatinine and Urea Clearance
 Tubular secretion occurs but there is little adaptive
ability to increase secretion in the presence of
increased serum levels
 Decreased GFR will cause increased Cr
 BUN both filtered and reabsorbed and excreted
primarily by Glomerular filtration

90. Plasma Creatinine & GFR

91. Renal Failure
 Chronic Renal Failure
 Sodium and Water Balance
 Increased sodium delivered to the tubules in
chronic renal failure
 Need to increase the excretion in order to maintain
serum levels within narrow range
 Tubule will decrease Reabsorption and increase
excretion
 Increased problem with reabsorbing sodium with
decreased GFR to 25%: increased loss

92. Renal Failure
 Chronic renal failure
 Potassium
 Control mediated by distal tubule excretion in
response to aldosterone
 Initially decreased renal function can be controlled
at normal intake levels with increased tubular
secretion and increased loss through the bowel
 As kidney function decreases total body K
increases and can be a factor in the decision to
start dialysis

93. Renal Failure
 Chronic Renal Failure
 Acid Base Balance
 Hydrogen ions are secreted from the renal tubules
and excreted in the urine in combination with
phosphate and ammonia buffers
 Early stages pH maintained by increased acid
secretion and bicarbonate reabsorption
 Later stages decreased adaptive ability with
increased metabolic acidosis

94. Renal Failure
 Phosphate and Calcium Balance
 Renal failure produces decreased phosphate
excretion, decreased renal formation of 1,25-
(OH)2 Vitamin D, and hypocalcemia
 Elevated plasma phosphate levels binds Ca
causing hypocalcemia and stimulation of
Parathyroid Hormone
 PTH increases release of CA from bone and
increased phosphate excretion

95. Renal Failure
 Chronic Renal Failure
 Ca and Phosphate Balance
 Decreasing GFR will gradually overcome PTH’s
ability to control serum phosphate levels
 Hyperphosphatemia, hypocalcemia, and increased
PTH will increase bone dissolution and be
responsible for the development of osteomalacia
 Impaired synthesis of activated Vitamin D in the
kidney will also reduce intestinal absorption of CA
and enhance the problem

96. Renal Failure
 Hematocrit
 Normocytic normochromic anemia secondary to
decreased levels of erythropoetin
 There can also be decreased RBC life span and
bleeding that can add to the anemia
 Hypertriglyceridemia
 Accelerated atherosclerosis, decrease lipoprotein
lipase within the capillary and decrease hepatic lipase
all decrease the breakdown, add to atherosclerosis

97. Renal Failure
 Chronic Renal Failure
 Proteins
 Muscle protein decreases
 Decreased levels of albumin. complement, and
transferrin
 Proteinuria occurs with increased risk for kidney
damage
 Carbohydrates
 Glucose intolerance secondary to insulin resistance

98. Clinical Presentation of Renal
Failure

99.  Tests of Renal Function
Clearance and glomerular filtration rate
 Inulin
 Inconvenient
 Creatinine
 Clinical choice 24 hr urine volume and serum creatinine level
 Cockcroft-Gault formula
 GFR = (140 - age) x wt (kg)__ (x.85 if female)
72 x serum creatinine
 Blood tests
 Plasma creatinine concentration
 Normal 0.7-1.2 mg/dl
 50% GFR reduction = Cr 2x normal value
 Best for monitoring CRF progression
 Blood urea nitrogen (BUN)
 Normal range 10-20 mg/dl
 Varied by diet and hydration

100.  Urinalysis Tests of Renal Function
 Urine color
 Light yellow, clear
 Urine pH
 4.5 – 8.0
 Specific gravity
 1.016-1.022
 Correlates with osmolality
 Acidic or alkaline urine effects results
 Urine sediment
 RBCs
 Casts
 WBC, RBC, Epithelial
 Crystals
 Normal or pathologic
 WBCs
 Infection

101. Tests of Renal Function
 Urinalysis
 Reagent strips (dipsticks)
 Glucose
 Bilirubin
 Urobilinogen
 Leukocyte esterase
 Nitrites - infection
 Ketones
 Proteins
 RBCs, hemoglobin, and myoglobin

102. Aging and Renal Function
 Decrease in kidney size
 Decrease in renal blood flow and GFR
 Number of nephrons decrease due to
renal vascular and perfusion changes
 Glomerular capillaries atrophy
 Tubular transport response decreases
 Increased bladder symptoms
 Urgency, frequency, and nocturia

103. The End
 Questions?
 Thanks