2. Kidney functions
Other system organs
General system
anatomy
Kidney str & fxn
Nephron – basic fxnal
unit of the kidney
Overview
3. Kidney Functions
Filter 200L blood/day to eliminate:
Toxins
Metabolic wastes
Excess ions
Regulate blood volume
~ 5 L
Regulate chemical makeup of the blood
300 mmoL concentration of solutes (i.e.
sodium, potassium, zinc)
Maintain the proper balance between H20 &
salts, and acids and bases.
4. Other Kidney Functions
Gluconeogenesis
Production of renin
Production of erythropoietin
Activation of vitamin D
5. Other Urinary System Organs
Urinary bladder – provides
temp. storage reservoir for
urine
Paired ureters – transport urine
from the kidneys to the bladder
Urethra – transports urine from
the bladder out of the body
6.
7. Ureters
Slender tubes-carry urine: kidneys to the bladder
Ureters enter the base of the bladder through the
posterior wall
As bladder pressure increases (increased urine
volume in bladder), distal ends of ureters get closed
off & prevent backflow of urine into ureters.
Tri-layered wall
Epithelial mucosa
Smooth muscle
Fibrous connective tissue
Ureters actively propel urine to the bladder via response
to smooth muscle stretch
8. Urinary Bladder
Smooth, collapsible, muscular sac that temporarily
stores urine
Lies on the pelvic floor posterior to the pubic symphysis
Males – prostate gland surrounds the neck inferiorly
Females – anterior to the vagina and uterus
Trigone – triangular area outlined by the openings for
the ureters and the urethra
Clinically important because infections tend to persist
in this region
9.
10. Urinary Bladder
The bladder wall has three layers
epithelium
muscular layer
fibrous layer
The bladder is distensible &
collapses when empty
As urine accumulates, the bladder expands without
significant rise in internal pressure
11. Bladder Cancer
60,000 cases a year in the US
13,000 deaths per year
4 times more likely to occur in men
Most frequently b/w 60-70 yrs of age
Causes ?
Environmental exposures
High rates in employees in chemical and rubber
plants
Prognosis for metastatic bladder cancer is poor
Spreads to bone, lymphatic system
12. Tissue engineering: Bladder
Bladder disease
Increased pressure in poorly functioning bladder
leads to kidney damage
Reconstruction w/ small intestine tissue
Grow own bladder cells in culture for 7-8 weeks
Attached ‘new bladder’ to old bladder in 7, 4-19 yr old
children
2-5 yrs later: improved bladder function in all
subjects
14. Sphincters keep the urethra closed when urine is not
being passed
Internal sphincter – involuntary sphincter at the
bladder-urethra junction
External sphincter – voluntary sphincter surrounding
the urethra as it passes through the urogenital
diaphragm
Levator ani muscle – voluntary urethral sphincter
15.
16.
17. The female urethra is tightly bound to the anterior
vaginal wall
External opening lies anterior to vaginal opening and
posterior to the clitoris
The male urethra has 3 named regions:
Prostatic urethra – runs within the prostate gland
Membranous urethra – runs through the urogenital
diaphragm
Spongy (penile) urethra – passes through the penis
and opens via the external urethral orifice
19. Prostate Gland:
Size of walnut
Surrounds neck of urinary
bladder and urethra
Secretes fluid that forms part
of semen
20. Benign Prostate Disorders
Infection
Inflammation
Enlarged prostate
High blood levels of PSA
Impotence
Incontinence and or retention
S&S of prostate disorders
Interference of flow
Change in urinary freq. urination
Pain
21. Prostate CA
Increased likelihood with enlarged prostate
(hypertrophy).
60% of prostate cancers discovered remain localized
5 yr survival = 100%
10 yr survival = 68%
15 yr survival = 52%
In past 20 yrs survival has increased from 67-93%
22. Other Considerations
PSA check annually after age 50
High risk males should begin screening
earlier
Risk factors
Age
Race
African Americans are 61%
more likely to get prostate CA &
2.5x more likely to die from dx
Diet: high fat / low fiber
Obesity
Environmental exposures
23. Kidney Location & Structure
Bean-shaped
extends from T-12 to L-3.
R kidney hangs lower than left.
crowded by the liver
24. Layers of Tissue Support
Renal capsule – fibrous capsule surrounding kidneys
that gives support & helps prevent infection
Adipose capsule – fatty mass that cushions the kidney
and helps attach it to the body wall
Renal fascia – outer layer of dense fibrous connective
tissue that anchors the kidney
25.
26. Internal Structure of Kidney
Cortex – the light colored, granular superficial region
Medulla – exhibits cone-shaped medullary (renal)
pyramids
Pyramids are made up of parallel bundles of urine-
collecting tubules
Renal columns are inward extensions of cortical tissue
that separate the pyramids
Pyramid plus its surrounding capsule, constitute a
lobe
27.
28. Large blood flow to kidney:
~25% (1200 ml) of BF from heart
into systemic circulation, flows
through the kidneys per minute.
29. The Nephron
Nephrons: stral & fxnal units of the kidneys that form
urine:
Glomerulus: a capillary bed associated with a renal
tubule
Bowman’s capsule: cup-shaped end of a renal tubule
that surrounds glomerulus.
Renal corpuscle – the glomerulus and its Bowman’s
capsule
Glomerular endothelium –epithelium that allows
solute-rich, virtually protein-free filtrate to pass from
the blood into the glomerular capsule
30.
31.
32.
33. Renal Tubule
Proximal convoluted tubule (PCT):
Composed of cuboidal cells with numerous microvilli
and mitochondria
Reabsorbs water and solutes from filtrate and
secretes substances into it
Loop of Henle: a hairpin-shaped loop of the renal tubule
Distal convoluted tubule (DCT):
cuboidal cells w/o microvilli that function more in
secretion than reabsorption
34. Nephrons
Cortical nephrons – 85% of nephrons; located in the
cortex
Juxtamedullary nephrons:
Located at the cortex-medulla jxn
Have loops of Henle that deeply invade the medulla
Have extensive thin segments
Are involved in the production of concentrated urine
35. Capillary Beds of the Nephron
B/P in the glomerulus is high:
Kidney is very well vascularized
High density of blood vessels
Blood flow within nephron controlled by afferent
arteriole
Fluids & solutes are forced out of the blood
throughout the entire length of the glomerulus
36. Characteristics of Normal Urine
• Complex watery (95%) solution of organic &
inorganic wastes (5%)
• Color: pale, straw to amber color
– If highly concentrated:
•Hematuria / orange color
–‘milky’ / turbid : infection
• Clarity: transparent
• Odor: faintly aromatic; will change to ammonia
if standing too long. Some drugs and vegetables
(asparagus) alter the usual odor
• pH: 5.5 – 7.0
– Will turn alkaline if left standing
37. Characteristics of Normal Urine
Specific Gravity:
Indicates concentration of urine (# of particles in it)
Normal values = 1.01 – 1.03
Measured by comparing the weight of pure water
vs. urine
Urine should not contain:
Albumin
Glucose
Ketones
Blood / Pus / Bacteria
Calculi
Bile
38. Normal Output
Normal voiding: 250 – 500cc
Normal 24 hour voiding: 1000
- 1500cc
Normal hourly: 30 -120cc
< 30cc / hr may indicate renal
pathology
39. Chemical Composition of Urine
Urine is 95% water and 5% solutes
Nitrogenous wastes include urea, uric acid, and
creatinine
Other normal solutes include:
Na+, K+, phosphate, and sulfate ions
Calcium, magnesium, and bicarbonate ions
Abnormally high concentrations of any urinary
constituents may indicate pathology
40.
41. Trauma, Ischemia & Kidney Damage
Ischemia – decreased oxygen supply to nephron because
there is decrease in blood flow
Decreased blood flow to nephron which is chronic can
lead to Kidney Damage.
Anything that causes afferent arteriole prolonged
constriction
42. Renal Clearance Diagnostic Test
The volume of plasma that is cleared of a particular
substance in a given time
Clearance tests are used to:
Determine the GFR
Detect glomerular damage
Follow progress of renal dx
43. Renal Clearance
RCR = UV/P
RCR = renal clearance rate
U = concentration (mg/ml) of the substance in urine
V = flow rate of urine formation (ml/min)
P = concentration of the same substance in plasma
44. Urinary Disorders: S&S
Changes in urinary frequency
or volume
Dark urine
Pain with urination
Kidneys unable to regulate
body H2O & Na+ balance
Edema (fluid retention) &
or High B/P
45. Urinary Tract Patho
Urinalysis
General health of urinary sys
Drug testing
Proteinuria
Glomerular damage
Ketonuria
Diabetes or starvation
Glucosuria
Diabetes
Solids in urine - sediment examined.
Types of cells: RBCs ; WBCs
Ability of kidneys to concentrate urine
Administer ADH
become more concentrated since more fluid
should be retained
46. Urinary Tract Infections
Occurs in any portion of urinary
tract
10 - 20% of all women in US have
lower UTI at some time
Limited occurrence
Effects of urea (kill bacteria)
Acidic pH of urine
Washing out of bacteria during
voiding
Minimize urine reflux
48. Kidney Infection
Bacterial or viral
Urinary obstruction
causes backflow of urine from bladder to kidneys
From blood infection
Most cases in women
Symptoms
Pain / Fever
Increased urinary frequency
Treatment
Longer use of ABx thpy
49. Urolithiasis
Presence of stones in the
urinary tract
Calculi formed by:
Calcium oxalate
Calcium phosphate
Uric acid
Calculi can pass through
the urinary tract and/or
cause an obstruction
50. Urolithiasis
Assessment:
Acute, sharp, intermitte
nt pain (ureteral colic)
Dull, tender ache in the
flank (renal colic)
N&V, Fever & chills
Hematuria / Pyuria
Abd. Distention
Diagnostic Findings:
KUB: visible calculi
IVP: size & loc of stones
Renal sonogram &
Spiral CT scan
Stone Analysis –
detection of type of
stone
55. Polycystic Kidney Disease
Genetic disorder - 500,000 cases in US
Large cysts form in the kidneys
Kidney hypertrophy
Over time, decreasing kidney function as nephrons units
are replaced by cysts
Dialysis or transplant
50% with PKD progress to kidney failure (end stage
renal disease)
4th leading cause of kidney failure
No cure except kidney transplant
57. Acquired Cystic Kidney Disease
From long-term kidney dialysis and end-stage renal
disease
90% of people on dialysis for 5 yrs develop ACKD
Cysts may bleed
Increased risk of kidney cancer (very rare)
2 times as likely with ACKD
58. Diabetic Nephropathy
Diabetes - Abnormally high blood glucose
Causes major problems with blood chemistry
including osmotic balance
Kidneys can remove all extra glucose from blood
Kidneys must work extra hard to do this
Larger urine volume as kidneys must excrete excess
glucose
59. Diabetic Nephropathy (con’t)
Prolonged high blood glucose causes nephropathy
Damage to the glomerulus and the filtering system
Proteins and blood cells that would normally not be
filtered appear in the urine
Kidney function is compromised
Diabetic nephropathy is leading cause of kidney failure
in United States
60. Diuretics
Chemicals that enhance the urinary output include:
Any substance not reabsorbed
Substances that exceed the ability of the renal tubules
to reabsorb it
At transport max
Substances that inhibit Na+ reabsorption
Na+ drives the reabsorption of fluid
61. Osmotic diuretics include:
High glucose levels
H2O carried out w/ glucose
Alcohol
inhibits release of ADH
Caffeine and most diuretic drugs
inhibit Na+ reabsorption
Lasix
inhibit Na+ associated transporters
62.
63. Diuretics to Treat Urinary System Dx
Diuretics: increase urine volume
Aldosterone antagonists: block sodium retaining
effect of aldosterone
More sodium remains in renal tubule
More sodium excreted
Where sodium goes, water goes (increased fluid
elimination
Sodium and chloride reabsorption inhibitors
(thiazides)
block reabsorption of sodium, potassium and
chloride
Increased salt and water elimination
64.
65. Treatment of Renal Failure
Will develop after both kidneys are damaged
Restrict water, salt and protein intake
Minimizes volume of urine produced
Prevent production of large amount of nitrogenous
waste
Hemodialysis
Uses artificial membrane (replaces glomerular
filtration) to filter blood.
Diffusion of small ions
Minimal loss of blood protein
Dialysis fluid
K+, phosphate ions, sulfate
ions, urea, creatinine, uric acid go into dialysis
66. Treatment of Renal Failure
Dialysis
15 hrs per week
Dialysis centers
Transplantation
15,000 transplants in 2003
1 yr success rate is 85-95%
Immunosupressive drugs to reduce transplant
rejection
67.
68. Urinary Incontinence – Multiple Etiologies
Normal effect of aging or pathology
Stretching of pelvic floor during childbirth
Incontinence during sneezing and coughing (stress
incontinence)
Prostate removal
Neurogenic bladder dysfunction
Treatment
Kegel exercises: tightening pelvic muscles as if trying
to stop urination
69.
70. Did you know?
Infants have small bladders and the kidneys cannot
concentrate urine, resulting in frequent micturition
Control of the voluntary urethral sphincter develops
with the N System about age 1
E. coli bacteria account for 80% of all urinary tract
infections
Sexually transmitted diseases can also inflame the
urinary tract and result in urinary tract infections
Kidney function declines with age, with many elderly
becoming incontinent
Editor's Notes
Gluconeogenesis during prolonged fasting – as we also saw in ANS modulation.Production of renin to help regulate blood pressureProduction of erythropoietin to stimulate red blood cell production in bone marrow given to CA pts – some studies dispute effectiveness / efficacy.Activation of vitamin D
Effects of gravity – huge contribution in collection of urine in the bladderMuscular composition of ureters – smooth muscle.Would urine still collect if we upside-down?
The Vas deferens looks like it is running through the bladder … it is not!
Change could be increased or decreased urinary frequency.PSA = (prostate specific antigen)
Push to increase awareness – as well as checking for PSA markers.
Digital Rectal Exam.
Begin to appreciate the level of vascularization.
Kids are heavily protected!Note the Anterior and posterior renal fascia.
Arterial flow in & venous flow out of the kidneys follow similar paths.
Is urine sterile?If myoglobin, hemoglobin or red blood cells in urine: red or brown urineIf pus, bacteria, lipids, or alkaline (higher pH): white cloudy urineFoamy urine: excessive protein in urine
Women have much shorter urethras. If repeated lwr UTIs – need to re-educate front to back wiping.
Lasix – excellent diuretic, cheap – but non-K sparing. Need to educate to increase your K intake.