Renal powerpoint-jaime

  1. Structure of a Nephron-Bowmans capsule
    • Surrounds glomeruli capillaries
    • Continuous with first portion of nephron
    • Blood is ultrafiltered through this space
    • First step in urine formation

    What remains of nephron has specialized cells that serve for reabsorption and secretion.
  2. Functional unit of kidney
    • Nephron
    • Each kidney contains approximately 1 million nephrons.
    • Consists of glomeruli and renal tubule
  3. First step in urine formation happens where
    Bowmans capsule
  4. Nephron comprised of 5 segments
    • 1. Proximal convoluted tubules
    • 2. Proximal straight tubule
    • 3. Loop of Henle (thin descending, thin ascending, thick ascending)
    • 4. Distal convoluted tubule
    • 5. Collecting ducts
  5. 2 types of nephrons
    • 1. Superficial cortical nephrons
    • 2. Juxtamedullary nephrons
  6. Superficial cortical nephrons
    • glomeruli in outer cortex
    • short loops of Henle
    • descend only into outer medulla
  7. Juxtamedullary nephrons
    • glomeruli near the coritocomedullary border
    • Larger
    • Higher flow rates
    • Long loops of Henle
    • Descend deep into inner medulla and papilla- essential for formation of concentration of urine.
  8. Afferent arterioles
    • Deliver blood to the glomeruli capillaries.
    • BLOOD TO!!
  9. Efferent arterioles
    Blood leaves the glomeruli capillaries

    blood then delivered to secondary capillary network.

  10. Renal Cortex
    Outer region of kidney located just under renal capsule
  11. Renal Medulla
    A central region , divided into outer and inner medulla

    Outer medulla has outer stripe and inner medulla has inner stripe
  12. Papilla
    The innermost tip of the inner medulla and empties into pouches called minor and major calyces, which are extensions of ureter.
  13. Water is how much of body weight?
  14. Relationship between water content and body weight is clinically important
    3 Kg weight loss = 3 liters loss of total body water.
  15. Plasma = what percentage of blood volume
    What makes up other portion of blood volume?
    • 55%
    • Cells=45%
  16. Plasma proteins constitute _____ % of plasma by volume?

    The other 93% of plasma volume is plasma water.
  17. Mannitol as a marker for volume
    • In the ECF
    • Cannot cross cell membrane

    *choose marker based on where it will go. Mannitol will not cross cell membrane so it stays in the ECF.
  18. Innulin as a marker for volume
    • Innulin is same as mannitol, it cannot cross cell membrane.
    • It is found in ECF not in the ICF
  19. Volume in a compartment depends on the _________?
    Solute it contains.
  20. Normal value for osmolarity of the body fluids is__________?
    290 mOsm/L

  21. Isosmotic volume contraction
    Example Diarrhea, sunburn
    Plasma protein=
    • ECF= goes down
    • ICF= N.C
    • Osmolarity=N.C
    • Hematocrit= goes up
    • Plasma Protein= goes up
  22. Hyperosmotic volume contraction
    Example: sweating, fever, diabetes
    Plasma protein=
    • ECF= goes down
    • ICF=goes down
    • Osmolarity= goes up
    • Hematocrit= no change
    • Plasma Protein= goes up
  23. Hyposmotic volume contraction
    Example: Adrenal insufficieny
    Plasma Protein=
    • ECF=goes down
    • ICF=goes up
    • Osmolarity=goes down
    • Hematocrit=goes up
    • Plasma Protein=goes up
  24. Isosmotic volume expansion
    Example: Infusion of isotonic NaCl
    plasma protein
    • ecf= goes up
    • icf=no change
    • osmolarity= no change
    • hematocrit= goes down
    • plasma protein= goes down
  25. Hyperosmotic volume expansion
    Example: High NaCl intake
    Plasma Protein=
    • ECF= goes up
    • ICF= goes down
    • Osmolarity= goes up
    • Hematocrit= goes down
    • Plasma Protein= goes down
  26. Hyposmotic volume expansion
    Example: SIADH
    Plasma Protein=
    • ECF= goes up
    • ICF= goes up
    • Osmolarity= goes down
    • Hematocrit= No change
    • Plasma protein= goes down
  27. Renal clearance equation
    C=U x V/P

    • C= clearance (ml/min)
    • [U]x= urine concentration (mg/ml)
    • V= urine flow per minute (ml/min)
    • [P]x=plasma concentration (mg/ml)

    Renal clearance is a ration of urinary excretion to plasma concentration.
  28. Solve for renal clearance

    Urine concentration=100 mg/ml
    Plasma concentration = 2 mg/ml
    Urine flow= 1 ml/min
    • C=U x v/p
    • C= 100 x 1/2= 50 ml/min
  29. What substance clearance is equal to its GFR?

    Unique properties

    Glomerular Marker
  30. Kidneys receive about ______% of cardiac output?

    L/min ?

    1.25 L/min
  31. Renal blood flow and sympathetic stimulation
    Vasoconstriction for activation of alpha 1 receptors

    Because there are far more alpha receptors on afferent arterioles (taking blood to capillaries) and this increases sympathetic nerve activity- this causes decreased GFR and RBF (renal blood flow) *attempts to raise BP at the expense of kidneys.
  32. Renal blood flow =
    RPF( renal plasma flow)

    RBF= RPF/1-HCT
  33. Ficks Principle
    The amount of a substance entering the kidney via the artery equals the amount leaving via the vein.
  34. [RA]pah=
    [PAH] in renal blood flow
  35. [RV]pah=
    • [PAH] in renal vein
    • PAH- substance used to measure RPF with Ficks principle
  36. Measuring effective Renal Plasma Flow

    Effective RPH=
    effective RPF= [U]pah X V/[P]pah=Cpah

    • [U]pah= urine concentration of pah (mg/ml)
    • V= urine flow rate (ml/min)
    • [P]pah= plasma concentration of PAH (mg/ml)
    • Cpah= clearance of PAH (ml/min)
    PAGE 250-251
  38. GFR of inulin- measurement of GFR by clearance of glomeruli marker
    Use Renal clearance equation or GFR (which is same)

    Urine concentration=150 mg/ml
    Plasma concentration= 1 mg/ml
    Urine Flow= 1 mg/min
    • C= (Urine concentration) [U]x X (urine flow) V/( plasma concentration) [p]x
    • or
    • GFR= [U]inulin x V/[P]inulin=C inulin

    • 150 x 1/1=
    • GFR= 150ml /min
  39. Filter load
    • Use renal clearance equation
    • GFR  x plasma concentration
  40. GFR is the first step in ________?
    Happens where________?
    • Urine formation
    • Bowmans capsule
  41. Excretion=
    Amount of substance excreted per unit of time

    • V x U
    • urine flow rate x urine concentration of X
  42. Reabsorption or secretion
    Filter load - excretion rate
  43. Starling Forces
    4 pressures
    • two hydrostatic pressure- one in capillary blood, and one in interstitial fluid
    • two oncotic pressures= one in capillary blood, and one in interstitial fluid
    • Oncotic pressure in Bowman's capsule is 0
  44. Starling forces
    Kf= filtration coefficient
    GFR=Kf= (Pgc-Pbs) - (pie symbol not in parenthesis)gc

    • Pgc-Pbs= hydrostatic pressure of glomeruli capsule - hydrostatic pressure of Bowman's capsule
    • (Pie)gc= oncotic pressure in glomeruli capsule
  45. Changes in GFR are cause by changes in the __________?
    Starling Pressures
  46. Effects of Changes in Starling Pressure
    Constriction of afferent arterioles
    • RPF=Decreased
    • GFR=Decreased
    • Pgc=decreased b/c of decreased blood flow
    • FF (GFR/RPF)= No change
  47. Effects of Changes in Starling Pressure
    Constriction of efferent arterioles
    • RPF= decreased
    • GFR- increased  (opposite of afferent end)
    • Pgc- increases
    • Filtration fraction (GFR/RFP)= increased
  48. Effects on changes in Starling Pressure

    Increased Plasma protein concentration
    FF (GFR/RPF)=
    • RPF= N.C.
    • GFR= Decreases
    • FF=Decreases
  49. Effects on changes in Starling Pressure

    Decreased plasma protein concentration
    • RPF= N.C
    • GFR= increase
    • FF= increase
  50. Effects on changes in Starling Pressure

    Constriction of Ureter
    • RPF= N.C.
    • GFR= decreased
    • FF= decrease
  51. Can use ______ (besides inulin) for calculation of GFR.

    Use same calcuation

    Slightly overestimates GFR

    GFR= [U]creatinine x V/[P] creatinine = C of creatinine
  52. Renal blood flow and Angiotensin II simulation
    • Vasoconstrictor at both sides- afferent and efferent
    • Efferent more sensitive
    • Low levels increase GFR (constrict efferent)
    • High levels decrease GFR (constrict afferent and efferent)
  53. Renal blood flow and Prostoglandins stimulation

    What effect does NSAIDS have?
    • Produced in kidneys, causes vasodilation of both
    • Protective of RBF (long term vasoconstriction after hemorrhage can cause renal failure)
    • Modulated constriction caused by SNS and release of angiotensin II
    • NSAIDS- inhibit this synthesis of prostaglandins and therefore interfere with protective effects of prostaglandins on renal function following hemorrhage
  54. Filtration
    amount of substance filtered into Bowman's space per unit of time = filtered load
  55. Reabsorption
    water and many solutes are reabsorbed from the glomerular filtrate into the peritubular capillary blood
  56. Secretion
    • Few substances are secreted from peritubular capillaries
    • Organic acids, organic bases, and potassium
    • Mechanism for excreting substances in the urine
  57. Filtered Fraction
  58. Cellular Mechanism for Glucose reabsorption
    (carrier mediated)
    • In proximal tubule
    • 2 steps
    • 1.Sodium glucose co-transport- sodium and glucose released into ICF, and potassium moved out -
    • 2.facilitated glucose transport across peritubular membrane  (no energy required).
  59. Tmax of reabsorption=
    Tmax of renal reabsorption=
    • 300
    • 200
  60. Reabsorption of glucose tmax less than 200
    all filtered glucose is reabsorbed
  61. Reabsorption of glucose tmax more than 200
    All filtered glucose is not reabsorbed.
  62. Reabsorption of glucose tmax above 300
    All carriers are saturated, no reabsorption will take place
  63. Causes of glycosuria (spilling of glucose into the urine)
    Normal plasma glucose is 70-100 and all is reabsorbed, some conditions can alter this level causing glycosuria:
    • Uncontrolled DM
    • Pregnancy
    • congenital abnormalities in sodium glucose transport
  64. Urea
    By what-
    • Most segments of nephron reabsorb urea
    • Urea reabsorbed by simple diffusion and is freely filtered.
    • Urea follows the same pattern as water. As water reabsorption increases so does urea reabsorption.
  65. PAH as a marker for volume
    para-aminohippuric acid- the substance used to measure RPF (renal plasma flow) in Ficks principle
  66. PAH secretion
    PAH- (para-aminohippuric acid) used as a marker for RPF
    filtered across capillary and secreted from peritubular capillary blood into tubular fluid
  67. Most important function of the kidney
    • maintaining a normal sodium balance
    • sodium excretion should equal sodium intake

    • Na freely filtered across glomerular capillaries and reabsorbed throughout nephron.
    • Excreted 1%
    • Reabsorbed 99%
  68. 99 % of Na in Kidney reabsorbed where at?
    • 67%- Proximal convoluted tubule
    • 25%-thick ascending loop of henle
    • 8%  distal convoluted tubule and collection ducts
  69. If 67% of sodium reabsorbed, how much water is reabsorbed?
    • 67%
    • Where sodium goes, water follows
  70. Sodium reabsorption in proximal convoluted tubule
    What type of transport
    • 67%
    • Co-transport with bicarb, organic solutes, amino acids, and glucose
    • 100 % of glucose and amino acids reabsorbed
    • Na-H exchanger- causes net absorption of bicarb
    • 85% bicarb reabsorbed here.
  71. What part of nephron does Lasix work on
    Thick ascending limb of Henle
  72. Thick ascending loop of Henle
    Reabsorbs by what mechanism?
    What kind of transport takes place here?
    • Reabsorbs a significant amount of sodium by an active mechanism
    • Na-K-2Cl co-transporter= three ion co-transport, energy from sodium gradient, maintained by sodium potassium pump
    • Site for loop diuretics, lasix
  73. What part of nephron does thiazide diuretics work on
    Early distal convoluted tubule
  74. Distal Tubule and reabsorption
    percent of Na
    Dependent on ?
    what type of transport takes place here
    What diuretics work here?
    • 8% of Na reabsorption
    • Load dependent= the more you bring to it the more will be absorbed.
    • Na-Cl co-transport
    • Site for thiazide diuretics
  75. Late distal tubule and collecting ducts
    What type of cells?
    What type of regulation?
    • Principle and alpha cells
    • Hormonal regulation: aldosterone, water, reabsorption
    • Aldosterone-increase Na reabsorption in principle cells
    • Water- without water permeability is low.
  76. Potassium balance
    • 98% ICF
    • 2% ECF
    • Freely filtered
    • Excretion of potassium must be equal to the intake.
  77. How does insulin affect internal potassium balance?
    Stimulates potassium uptake in cells.
  78. How does H-K exchanger affect internal potassium balance?
    • alkaline= hydrogen decrease, hydrogen leaves and potassium enters
    • academia= k leaves and hydrogen enters
  79. How do beta 2 agonists affect internal potassium balance
    Increase the sodium potassium pump causing a shift of potassium into the cells.
  80. How does alpha agonists affect internal potassium balance?
    shift of potassium out of cell
  81. How do alpha antagonists affect internal potassium balance
    take potassium into the cells.
  82. How does hyperosmolarity affect internal potassium balance?
    shifts potassium out of the cell
  83. How does lysis of cells affect internal potassium balance?
    Large amount of potassium is released from ICF
  84. What percent of Potassium is reabsorbed in the proximal convoluted tubule?
    what percent in thick ascending limb of henle?
    Distal convoluted tubule and collecting ducts?
    • 67%
    • 20%-diffuses to blood
    • Fine adjustments of potassium excretion, varies with diet
  85. Alpha intercalated cells in distal tubule and collecting ducts do what with low potassium diet?
    reabsorb potassium
  86. Principle cells in the distal tubule and collecting ducts do what with high potassium diet?
    Excrete potassium
  87. What increases Secretion of potassium
    • High potassium diet
    • Increase in aldosterone
    • Alkalosis
    • loop and thiazide diuretics
    • presence of large anions in lumen
  88. Spirolactone
    potassium sparing diuretic

    • inhibits actions of aldosterone (increases potassium excretion)
    • inhibits potassium excretion
  89. Renal handling of Calcium
    ______% to plasma proteins?
    ______% reabsorbed proximal convoluted tubule?
    ______% reabsorbed at thick ascending loop of henle
    ______% reabsorbed in distal tubule?
    • 40% bound to plasma proteins
    • 67% reabsorbed at proximal convoluted tubule
    • 25%
    • 8% reabsorbed in distal tubule
  90. Reabsorption of Phosphate

    _____% proximal convoluted tubule
    _____% proximal straight tubule
    • 70%
    • 15%
    • Exhibits tmax
  91. Magnesium

    ____% bound to plasma protein
    ____% reabsorbed in proximal tubule
    ____% reabsorbed in thick ascending loop of henle
    • 20%
    • 30%
    • 60%

    Loop diuretics inhibit magnesium reabsorption strongly.
  92. Regulation of body fluid osmolarity
    Response to water deprivation
    6 steps
    • 1. water is lost from body (if not replaced increase osmolarity of plasma)
    • 2. Increased osmolarity
    • 3. stimulation of receptors (stimulates thirst and ADH)
    • 4. ADH- increases permeability
    • 5. Increased water reabsorption in late distal tubules
    • 6. more water returned to body, osmolarity decreases
  93. Corticopapillary osmotic gradient
    Two processes
    1. countercurrent multiplication
         2 steps
    • function of the loop of henle
    • deposits NaCl deep into regions of the kidney
    • 1st step- single effect
    • thick ascending limb, no water is reabsorbed but NaCl
    • 2nd step-descending limb reabsorbs water
    • equilibrates with interstitial spaces
  94. Corticopapillary osmotic gradient
    Two processes
    2nd- Urea recycling
    Urea is recycled instead of thrown away in the urine.
  95. Countercurrent exchange
    • maintains the corticopapillary osmotic gradient.
    • passive
    • slow flowing blood
    • vasa recta
  96. 3 actions of ADH on renal tubules
    • 1. increases water permeability in the distal tubules and collecting ducts.
    • 2. Increases activity of na-k-2cl cotransporter in thick ascending limb
    • 3. increases urea permeability in the inner medullary collecting ducts (enhances urea recycling).
  97. Production of hyperosmotic urine
    • NaCl reabsorbed in thick ascending loop of henle- water reabsorption can not happen here.
    • Nacl reabsorbed by NaCl transporter in early distal tubule.
    • Principle cells become permeable to water in the presence of ADH
    • Urine is produced and osmolarity 1200 mOsm
  98. Production of hypoosmotic urine
    • Low circulating ADH
    • Tubular fluid diluted
    • Dilution continues
    • (most dramatic if ADH low or absent)
    • final urine does not equilibriate with interstitial fluid.
    • Final osmolarity= 75 mOsm/L
  99. Change in Pgc (hydrostatic pressure of glomeruli capsule) are produced by what?
    Changes in Pcg are produced by changes in resistance to afferent and efferent arterioles
  100. What type of transport takes place in thick ascending loop?
    Active transport
  101. Na-K-2Cl cotransporter
    All three ions are transported into the cell on the co-transporter

    Energy from sodium potassium pump
  102. Where is NaCl co-transport system located
    early distal convoluted tubule
  103. Were is Na-K-2Cl co-transporter located at
    Thick ascending limb
  104. Where is Na-glucose co-transporter located at?
    Proximal convoluted tubule
  105. What two things contribute to the establishment of the corticopapillary osmotic gradient?
    • Countercurrent multiplication
    • Urea Recycling
Card Set
Renal powerpoint-jaime
A&P midterm Fall 2013 Renal