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Renal 9 2011 - Reference
Bsc Nursing (BNurs2011)
Tamil Nadu Dr. M.G.R. Medical University
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Physiology of Body Fluids – PROBLEM SET, RESEARCH ARTICLE Structure & Function of the Kidneys Renal Clearance & Glomerular Filtration– PROBLEM SET R l ti f R l Bl d Fl REVIEW ARTICLE
Renal Physiology - Lectures
Regulation of Renal Blood Flow - REVIEW ARTICLE Transport of Sodium & Chloride – TUTORIAL A & B Transport of Urea, Glucose, Phosphate, Calcium & Organic Solutes Regulation of Potassium Balance Regulation of Water Balance 99. Transport of Acids & BasesTransport of Acids & Bases 10. Integration of Salt & Water Balance 11. Clinical Correlation – Dr. Credo 12. PROBLEM SET REVIEW – May 9, 2011 at 9 am 13. EXAM REVIEW – May 9, 2011 at 10 am 14. EXAM IV – May 12, 2011 Renal Physiology Lecture 9 Transport of Acids & Bases Chapter 8 Koeppen & Stanton Renal Physiology
- Excretingg Nonvolatile Acids ~ mmoles/day - CRUCIAL
- Bicarbonate Handling Reclaims ~ ALL Filtered Bicarbonate Generates NEW Bicarbonate
- Hyydro ggen Ion Re ggulation Titrates Filtered Non-HCO3- Buffers Titrates Endogenously Produced Ammonia
- Acid-Base Disorders
** Renal Failure Patient **
Patient Data Normal
PlasmaK+
PP Urea
BP
PPO4-
Hematocrit
PHCO3-
PpH
PCa2+
Amount FILTER/d Amount EXCRETE/d % REABSORB √ Water (L) 180 1 99. √ K+ (mEq) 720 100 86 1
REVIEW - Filtration & Reabsorption
√ K+ (mEq) 720 100 86. 1 √ Ca2+ (mEq) 540 10 98. HCO3- (mEq) 4,320 2 99 ++ √ Cl- ((mE q)q) 18,000 150 99. √ Na+ (g) 25,500 150 99. √ Glucose (mmol) 800 0 100 √ Urea (g) 56 28 50
Acid/Alkali
Intake
MetabolicMetabolic
Production
of
Acid/Alkali
Acid/Alkali Intake + Production = Acid/Alkali Excretion
Acid/Alkali
Excretion
Acid/Alkali Intake + Production Acid/Alkali Excretion
You Are What You Eat!
Fruit Alkali
Food Acid/Alkali Impact
Vegetables Alkali
Meat Acid
Grains Acid
Dairy
Products
Acid
“Typical” American Diet Results in Net Endogenous Acid Production (NEAP)
1. Independently control 2 major
buffering systems
Regulatory Systems – Acid Base
Balance of Body
CO 2
HCO3-
2. Regulate [H
+
] body fluids prevent
– acidosis
– alkalosis
Role of Kidney in Acid Base Balance
Normal pH body fluids
7 - 7.
Alkalosis
– H+ loss exceeds gain
– arterial plasma [H+] pH > 7.
AcidosisAcidosis
– H+ gain exceeds loss
– arterial plasma [H+] pH < 7.
Volatile Acid
Volatile Acid Production
(-CA)
CO 2 + H 2 O H 2 CO 3 HCO3-
+ H
15,000 mmol CO 2 produced/day –
oxidation carbohydrates fats amino
( CA) slow fast
oxidation carbohydrates, fats, amino
acids
Lungs eliminate CO 2
NONvolatile Acid Production
Organic, inorganic acid produced - NOT CO 2
Phosphoric, sulfuric, lactic acid
Metabolism protein, phospholipids, amino
acids
Acid NOT excreted lungs
Derived from metabolismDerived from metabolism,
diet, intestinal losses
NOT easily converted
CO 2
Renal Mechanisms
####### Nonvolatile acid production =
####### 70 mmol/day
Neutralized by HCONeutralized by HCO 3- in ECFin ECF
Kidneys must replenish lost HCO3-
Plasma = 25 mEq/L HCO3-
ECF = 14 L
Total HCO3- buffering 350 mEq H+
(25 mEq/L HCO3- X 14 L )
Deplete HCO3- in 5 days if not
####### replenished
Renal Mechanisms
HCO3- freely filtered glomerulus
- 180 L/day X 24 mmol/L = 4,320 mmole/d 700 mmol/d HCOl/d HCO 3 - to b ffbuff er nonvoll atilil e acidid production
Must reabsorb > 99% filtered HCO3-
Produce 70 mmol/d NEW HCO3-
Rely on H+ secretion
Usually NO HCO3- urine
1 Excreting Nonvolatile
Renal Physiology Lecture 9
1. Excreting Nonvolatile
Acids
2. Bicarbonate Handling
3. Hydrogen Ion RegulationHydrogen Ion Regulation
4. Acid-Base Disorders
Bicarbonate Handling by Nephron Fig 8-
reabsorption ~0% filtered load excreted urine
PT REABSORPTION Bicarbonate Fig 8-
Lumen ISF Pe r Retrieve Filtered HCO ritubular capilla r HCO 3 - HCO 3 -
- H+ H+ H+ 3 HCO 3 - 1 2 3 4 Reclaim HCO 3 -, NO HCO 3 - Excretion NO Net Secretion H+ HCO 3 - ry
Reabsorption of Bicarbonate
1. H+ secreted + filtered HCO3- H 2 CO 3
2. H 2 CO 3 CO 2 + H 2 O
carbonic anhydrase apical membrane
3. CO 2 + H 2 O
rapidly reabsorbed tubule highly permeable
4. Net effect
HCOHCO 3 - removed tubule lumenremoved tubule lumen HCO3- appears peritubular blood
5. 180 L/d x 24 mmol/L = 4,320 mmol/d
HCO3- filtered = 4,320 mmol/d H+ secretion
Formation Titratable Acid – Intercalated Cell
Titrate non-NH 3 , non-HCO 3 - Fig 8-
Lumen ISF
Pe
r
4
NEW
HCO 3 -
H+ HCO 3 -
H 2 PO 4 -
HPO42-
ritubular capilla
r
+ H+
1
2
3
4
Protonate Divalent Phosphate, Net Secretion H+
NEW HCO3- Added Plasma
H 2 PO 4 3 ry
Titratable Acid = Generation of New
Bicarbonate
Secreted H+ in lumen + filtered
urinary buffers (HPO42-; divalent
p hh osph that e)) othth er thth an HCOHCO3-
NEW HCO3- added plasma
Occurs only after filtered HCO3-
removed lumen
H+ excreted as H 2 PO4-
(monovalent phosphate)
Filtered Phosphate – Primary Urinary Buffers
PT Ammonium Excretion Fig 8-
ISF Lumen P e 1 NEW HCO 2 HCO 3 - NH4+ H+ NH 3 e ritubular capill a H+ 4 2 3 HCO 3 - 3 Protonate Ammonia, NET Secretion H+ New HCO3- Added Plasma a ry
Ammoniagenesis – Generation of New
Bicarbonate
Stimulated by acidosis
PT takes up glutamine & metabolized
to NHto NH 4 ++ (ammoni m)(ammonium)
NH4+ dissociates to NH 3 + H+
NH 3 diffuses to lumen, H+ secreted =
NH4+ lumen
HCOHCO 33 - moves into peritubularmoves into peritubular
capillaries
Acidify the urine by excreting NH4+
Addition Of A NEW Bicarbonate To Plasma
H
Secretion – Proximal Tubule
Fig 38-4AB
1. Na
/H
exchanger = 2/3 (major
NHE3)
80% Filtered HCO 3
Reabsorbed in PT
NHE3)
2. H
ATPase = 1/3 (pump)
80% Filtered HCO 3 Reabsorbed in PT
H+ Secretion – TAL & CD Fig 38-4CD
1. Na
/H
exchanger (major NHE3)
2 H
2. H ATPase (pump)
ATPase (pump)
3. H
/K
ATPase (pump)
~ 20% Filtered HCO3-
Reabsorbed in TAL, DCT, CD
Hydrogen Ion Secretion – Apical
1. Na+/H+ exchanger (major NHE3) -
allall PCT, TAL, DCTPCT, TAL, DCT
2. H
+
ATPase (pump) – mainly
intercalated cells CD; also PT, TAL, DCT
~ everywhere
3 H
+
/K
+
3. H ATP ( h ) CD
+
/K
+
ATPase (exchange pump) - CD
Bicarbonate Reabsorption – Basolateral
1. NaNa+ /HCO/HCO 33 - cotransportercotransporter (1:3,(1:3, NBC1NBC1))
2. Cl
-
/HCO3-
exchanger (anion
exchanger, AE)
Renal Handling of H+
Acid load handled by “dividing” 70
mmol/d of carbonic acid (H 2 CO 3 )
- excrete 70 mmol/d Hexcrete 70 mmol/d H+ into urineinto urine AND
- 70 mmol/d NEW HCO3- into blood THEREFORE
- NEW HCONEW HCO 3- neutt ralili zes d ildail y ll oad 70d 70 mmol nonvolatile acid
Sole Effective Route For Neutralizing
Nonvolatile Acids
1 Excreting Nonvolatile
Renal Physiology Lecture 9
1. Excreting Nonvolatile
Acids
2. Bicarbonate Handling
3. Hyydro ggen Ion Re ggulation
4. Acid-Base Disorders
Primary Acid/Base Disturbances
Metabolic Acidosis
1. Uncontrolled diabetes mellitus
22. RR enal f ill failure
3. Severe diarrhea
4. Ingestion of antifreeze
Metabolic Alkalosis
1. Vomiting
2. Nasogastric drainage
3. Antacids
Primary Acid/Base Disturbances
Respiratory Acidosis
1. Chronic pulmonary disease
22. Pulmonary edemaPulmonary edema
3. Sedative overdosage
4. Obstruction of airway
Respiratory Alkalosis
11. High altitude
2. Anxiety, pain, fear
hyperventilation
3. Gram-negative sepsis
Renal 9 2011 - Reference
Course: Bsc Nursing (BNurs2011)
University: Tamil Nadu Dr. M.G.R. Medical University
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