Acid Base Homeostasis

1. 1
ACID BASE HOMEOSTASISACID BASE HOMEOSTASIS
©Acid-Base homeostasis
involves chemicalchemical and
physiologicphysiologic processes
responsible for the
maintenance of the acidity of
body fluids at levels that
allow optimal function of the
whole individual

2. 2
ACID BASE HOMEOSTASISACID BASE HOMEOSTASIS
©The chemical processeschemical processes represent the first
line of defense to an acid or base load and
include the extracellular and intracellularintracellular
buffersbuffers
©The physiologic processesphysiologic processes modulate acid-
base composition by changes in cellular
metabolism and by adaptive responses in
the excretionexcretion of volatile acids by the lungslungs
and fixed acids by the kidneyskidneys

3. 3
ACID-BASE HOMEOSTASISACID-BASE HOMEOSTASIS
AcidsAcids
Acids = BasesAcids = Bases
Acids > BasesAcids > Bases
Acids < BasesAcids < Bases
AcidsAcids
Buffers

4. 4
ACID BASE HOMEOSTASISACID BASE HOMEOSTASIS
©The need for the existence of multiple
mechanisms involved in Acid-BaseAcid-Base
regulation stems from the critical importance
of the hydrogen ion (H
+
) concentration on
the operation of many cellular enzymes and
function of vital organs, most prominently
the brain and the heart

5. 5
ACID BASE HOMEOSTASISACID BASE HOMEOSTASIS
©The task imposed on the
mechanisms that
maintain Acid-BaseAcid-Base
homeostasis is large
ªMetabolic pathways
are continuously
consuming or
producing HH
++
ªThe daily load of
waste products for
excretion in the form of
volatile and fixed acids
is substantial

6. 6
EFFECTS OF pHEFFECTS OF pH
©The most general effect of pH changes are
on enzyme function
ªAlso affect excitability of nerve and
muscle cells
pH
pH
Excitability
Excitability

7. 7
ACID-BASE BALANCEACID-BASE BALANCE

8. 8
ACID-BASE BALANCEACID-BASE BALANCE
©Acid - BaseAcid - Base balance is primarily
concerned with two ions:
ªHydrogenHydrogen (H
+
)
ªBicarbonateBicarbonate (HCO
3
-
)
H
+
HCO
3
-

9. 9
ACID-BASE BALANCEACID-BASE BALANCE
©Derangements of
hydrogen and
bicarbonate
concentrations in
body fluids are
common in disease
processes

10. 10
ACID-BASE ACID-BASE
BALANCEBALANCE
©HH
++
ion has special
significance
because of the
narrow ranges that
it must be
maintained in order
to be compatible
with living systems

11. 11
ACID-BASE BALANCEACID-BASE BALANCE
Normal
©Primarily
controlled by
regulation of HH
++

ions in the body
fluids
ªEspecially
extracellular
fluids

12. 12
ACID-BASE REGULATIONACID-BASE REGULATION

13. 13
ACID-BASE REGULATIONACID-BASE REGULATION
©Maintenance of an acceptable pH range in
the extracellular fluids is accomplished by
threethree mechanisms:
ª1)1) Chemical BuffersChemical Buffers
¨React very rapidly
(less than a second)
ª2)2) Respiratory RegulationRespiratory Regulation
¨Reacts rapidly (seconds to minutes)
ª3)3) Renal RegulationRenal Regulation
¨Reacts slowly (minutes to hours)

14. 14
ACID-BASE REGULATIONACID-BASE REGULATION
©Chemical BuffersChemical Buffers
ªThe body uses pH buffers in the blood to guard
against sudden changes in acidity
ªA pH buffer works chemically to minimize
changes in the pH of a solution
Buffer

15. 15
ACID-BASE REGULATIONACID-BASE REGULATION
©Respiratory RegulationRespiratory Regulation
ªCarbon dioxide is an important by-product of
metabolism and is constantly produced by cells
ªThe blood carries carbon dioxide to the lungs
where it is exhaled
CO
2CO
2CO
2
CO
2
CO
2
CO
2
Cell
Metabolism

16. 16
ACID-BASE REGULATIONACID-BASE REGULATION
©Respiratory RegulationRespiratory Regulation
ªWhen breathing is increased,
the blood carbon dioxide level
decreases and the blood
becomes more BaseBase
ªWhen breathing is decreased,
the blood carbon dioxide level
increases and the blood becomes more AcidicAcidic
ªBy adjusting the speed and depth of breathing,
the respiratory control centers and lungs are
able to regulate the blood pH minute by minute

17. 17
ACID-BASE REGULATIONACID-BASE REGULATION
©Kidney RegulationKidney Regulation
ªExcess acid is excreted by
the kidneys, largely in the
form of ammonia
ªThe kidneys have some
ability to alter the amount of
acid or base that is
excreted, but this generally
takes several days

18. 18
ACID-BASE REGULATIONACID-BASE REGULATION
©Enzymes, hormones and ion
distribution are all affected by Hydrogen
ion concentrations

19. 19
ACIDSACIDS

20. 20
ACIDSACIDS
©Acids can be defined as a proton (HH
++
) donor
©Hydrogen containing substances which
dissociate in solution to release HH
++
Click Here

21. 21
ACIDSACIDS
©Acids can be defined as a proton (HH
++
) donor
©Hydrogen containing substances which
dissociate in solution to release HH
++
Click Here

22. 22
ACIDSACIDS
©Acids can be defined as a proton (HH
++
) donor
©Hydrogen containing substances which
dissociate in solution to release HH
++
H+
OH-
H+
OH-
H+
OH-
H+
OH-

23. 23
ACIDSACIDS
©Many other substance (carbohydrates) also
contain hydrogen but they are not classified
as acids because the hydrogen is tightly
bound within their molecular structure and it
is never liberated as free HH
++
H+
OH-
H+
OH-
H+
OH-
H+
OH-

24. 24
ACIDSACIDS
©Physiologically important acids include:
ªCarbonic acid (HCarbonic acid (H
22COCO
33))
ªPhosphoric acid (HPhosphoric acid (H
33POPO
44))
ªPyruvic acid (CPyruvic acid (C
33HH
44OO
33))
ªLactic acid (CLactic acid (C
33HH
66OO
33))
©These acids are dissolved in body fluids
Lactic acid
Pyruvic acid
Phosphoric acid

25. 25
BASESBASES

26. 26
BASESBASES
©Bases can be defined as:
ªA proton (HH
++
) acceptor
ªMolecules capable of accepting a
hydrogen ion (OHOH
--
)
Click Here

27. 27
BASESBASES
©Bases can be defined as:
ªA proton (HH
++
) acceptor
ªMolecules capable of accepting a
hydrogen ion (OHOH
--
)
Click Here

28. 28
BASESBASES
©Bases can be defined as:
ªA proton (HH
++
) acceptor
ªMolecules capable of accepting a
hydrogen ion (OHOH
--
)
H+
OH-
H+
OH-
H+
OH-
H+
OH-

29. 29
BASESBASES
©Physiologically important bases include:
ªBicarbonate (HCOBicarbonate (HCO
33
- -
))
ªBiphosphate (HPOBiphosphate (HPO
44
-2 -2
))
Biphosphate

30. 30
pH SCALEpH SCALE

31. 31
©pH refers to PPotential HHydrogen
©Expresses hydrogen ion concentration in water
solutions
©Water ionizes to a limited extent to form equal
amounts of HH
++
ions and OHOH
--
ions
ªHH
22OO HH
++
+ OH + OH
--
¨HH
++
ion is an acid
¨OHOH
--
ion is a base
pH SCALEpH SCALE

32. 32
©H
+
ion is an acid
pH SCALEpH SCALE

33. 33
©OH
-
ion is a base
pH SCALEpH SCALE

34. 34
©H
+
ion is an acid
©OH
-
ion is a base
pH SCALEpH SCALE

35. 35
©Pure water is NeutralNeutral
ª ( H
+
= OH
-
)
¨ pH = 7
©AcidAcid
ª( H
+
> OH
-
)
¨pH < 7
©BaseBase
ª( H
+
< OH
-
)
¨ pH > 7
©Normal blood pH is 7.35 - 7.457.35 - 7.45
©pH range compatible with life is 6.8 - 8.06.8 - 8.0
pH SCALEpH SCALE
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
H
+
H
+
H
+
H
+
OH
-
OH
-
OH
-
OH
-OH
-
H
+
H
+
H
+
H
+
OH
-
OH
-
OH
-
H
+
H
+
H
+
H
+
H
+
H
+
H
+
ACIDS, BASES OR NEUTRAL???ACIDS, BASES OR NEUTRAL???
1
2
3

36. 36
pH SCALEpH SCALE
©pH equals the logarithm (log) to the base 10
of the reciprocal of the hydrogen ion (HH
++
)
concentration
©HH
++
concentration in extracellular fluid (ECF)
pH = log 1 / HH
++
concentration
4 X 10
-8
(0.00000004)

37. 37
pH SCALEpH SCALE
©Low pH values = high HH
++
concentrations
ªHH
++
concentration in denominator of
formula
©Unit changes in pH represent a tenfold
change in HH
++
concentrations
ªNature of logarithms
pH = log 1 / HH
++
concentration
4 X 10
-8
(0.00000004)

38. 38
pH SCALEpH SCALE
©pH = 4 is more acidic than pH = 6
©pH = 4 has 10 times more free HH
++

concentration than pH = 5 and 100 times
more free HH
++
concentration than pH = 6
ACIDOSIS ALKALOSISNORMAL
DEATH
DEATH
Venous
Blood
Arterial
Blood
7.3 7.57.46.8 8.0

39. 39
pH SCALEpH SCALE

40. 40
pH SCALEpH SCALE

41. 41
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS

42. 42
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©An abnormality in one or more of the pH
control mechanisms can cause one of two
major disturbances in Acid-BaseAcid-Base balance
ªAcidosisAcidosis
ªAlkalosisAlkalosis

43. 43
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©AcidosisAcidosis
ªA condition in which the blood has too
much acid (or too little base), frequently
resulting in a decrease in blood pH
©AlkalosisAlkalosis
ªA condition in which the blood has too
much base (or too little acid), occasionally
resulting in an increase in blood pH

44. 44
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©Acidosis and alkalosis are not diseases but
rather are the results of a wide variety of
disorders
©The presence of
acidosis or
alkalosis provides
an important clue
to physicians that
a serious
metabolic
problem exists

45. 45
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©pH changes have dramatic effects on
normal cell function
ª1)1) Changes in excitability of nerve and
muscle cells
ª2)2) Influences enzyme activity
ª3)3) Influences KK
++
levels

46. 46
CHANGES IN CELL EXCITABILITYCHANGES IN CELL EXCITABILITY
©pH decrease (more acidic) depresses the
central nervous system
ªCan lead to loss of consciousness
©pH increase (more basic) can cause over-
excitability
ªTingling sensations, nervousness,
muscle twitches

47. 47
INFLUENCES ON ENZYME ACTIVITYINFLUENCES ON ENZYME ACTIVITY
©pH increases or decreases can alter the
shape of the enzyme rendering it non-
functional
©Changes in enzyme structure can result in
accelerated or depressed metabolic actions
within the cell

48. 48
INFLUENCES ON KINFLUENCES ON K
++
LEVELS LEVELS
©When reabsorbing NaNa
++
from the filtrate of
the renal tubules KK
++
or HH
++
is secreted
(exchanged)
©Normally KK
++
is
secreted in much
greater amounts
than HH
++
K
+
K
+
K
+
K
+
K
+
K
+
K
+
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
H
+

49. 49
INFLUENCES ON KINFLUENCES ON K
++
LEVELS LEVELS
©If HH
++
concentrations are high (acidosis) than
HH
++
is secreted in greater amounts
©This leaves less KK
++
than usual excreted
©The resultant KK
++
retention can affect cardiac
function and other systems
K
+
K
+
K
+
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
K
+
K
+
K
+
K
+
K
+

50. 50
©A relative increase in hydrogen ions results
in acidosis acidosis
ACIDOSISACIDOSIS
H
+
OH
-

51. 51
©A relative increase in bicarbonate results in
alkalosisalkalosis
ALKALOSISALKALOSIS
H
+
OH
-

52. 52
©AlkalosisAlkalosis
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
H
+
OH
-
©Acidosis Acidosis
H
+
OH
-

53. 53
©Normal ratio of HCOHCO
33
--
to HH
22COCO
33
is 20:1
ªHH
22COCO
33
is source of HH
++
ions in the body
©Deviations from this ratio are used to identify Acid-Acid-
BaseBase imbalances
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
BASE ACID
H
2
CO
3
H
+
HCO
3
-

54. 54
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©AcidosisAcidosis and AlkalosisAlkalosis can arise in two
fundamentally different ways:
ª1) Excess or deficit of CO1) Excess or deficit of CO
22
((Volatile AcidVolatile Acid))
¨Volatile Acid Volatile Acid can be eliminated by the
respiratory system
ª2) Excess or deficit of 2) Excess or deficit of Fixed AcidFixed Acid
¨Fixed AcidsFixed Acids cannot be
eliminated by the
respiratory system

55. 55
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©Normal values of bicarbonate
(arterial)
ªpH pH = 7.4
ªPCOPCO
22
= 40 mm Hg
ªHCOHCO
33
--
= 24 meq/L

56. 56
ACIDOSISACIDOSIS
©A decrease in a normal 20:1 base to
acid ratio
ªAn increase in the number of
hydrogen ions
(ex: ratio of 20:2 translated to 10:1)
ªA decrease in the number of bicarbonate
ions (ex: ratio of 10:1)
©Caused by too much acid or too little base
ACIDBASE

57. 57
ALKALOSISALKALOSIS
©An increase in the normal 20:1 base to acid
ratio
ªA decrease in the number of hydrogen
ions
(ex: ratio of 20:0.5 translated to 40:1)
ªAn increase in the number of bicarbonate
ions (ex: ratio of 40:1)
©Caused by base excess or acid deficit
ACIDBASE

58. 58
SOURCES OF SOURCES OF
HYDROGEN IONS HYDROGEN IONS
C C C C C C
H H H H H H
HHHHHH

59. 59
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©1) Cell Metabolism (CO1) Cell Metabolism (CO
22))
©2) Food Products2) Food Products
©3) Medications3) Medications
©4) Metabolic Intermediate by-products4) Metabolic Intermediate by-products
©5) Some Disease processes5) Some Disease processes

60. 60
SOURCES OF HYDROGEN IONSSOURCES OF HYDROGEN IONS
©1) Cellular Metabolism1) Cellular Metabolism of carbohydrates
release COCO
22
as a waste product
ªAerobic respiration
CC
66HH
1212OO
66  CO CO
22 + H + H
22O + EnergyO + Energy

61. 61
SOURCES OF HYDROGEN IONSSOURCES OF HYDROGEN IONS
©COCO
22
diffuses into the bloodstream where the
reaction:
COCO
2 2 + H+ H
22O HO H
22COCO
33
HH
++
+ HCO + HCO
33
--

©This process occurs in red blood cells
ªHH
22COCO
33
(carbonic acid)
ªAcids produced as a result of the
presence of COCO
22
is
referred to as a
Volatile acidVolatile acid

62. 62
SOURCES OF HYDROGEN IONSSOURCES OF HYDROGEN IONS
©Dissociation of HH
22COCO
33
results in the
production of free HH
++
and HCOHCO
33
--
©The respiratory system removes COCO
22
thus
freeing HCOHCO
33
--
to recombine with HH
++
©Accumulation or deficit of COCO
22
in blood
leads to respective HH
++
accumulations or
deficits
CO
2
H
+
CO
2
H
+
pH
pH

63. 63
CARBON DIOXIDE DIFFUSIONCARBON DIOXIDE DIFFUSION
COCO
22
COCO
22
Red Blood CellRed Blood Cell
Systemic CirculationSystemic Circulation
COCO
22HH
22OO HH
++
HCOHCO
33
--
++ ++
HCOHCO
33
--
ClCl
--
(Chloride Shift)(Chloride Shift)
COCO
22 diffuses into plasma and into RBC Within diffuses into plasma and into RBC Within
RBC, the hydration of CORBC, the hydration of CO
22 is catalyzed by is catalyzed by
carbonic anhydrasecarbonic anhydrase
Bicarbonate thus formed diffuses into plasmaBicarbonate thus formed diffuses into plasma
carboniccarbonic
anhydraseanhydrase
TissuesTissues
PlasmaPlasma

64. 64
CARBON DIOXIDE DIFFUSIONCARBON DIOXIDE DIFFUSION
COCO
22
Red Blood CellRed Blood Cell
Systemic CirculationSystemic Circulation
HH
22OO
HH
++
HCOHCO
33
--
carboniccarbonic
anhydraseanhydrase
PlasmaPlasma
COCO
22COCO
22
COCO
22COCO
22COCO
22COCO
22
COCO
22
Click for Carbon
Dioxide diffusion
++ ++
TissuesTissues
HH
++
ClCl
--
HbHb
HH
++
is buffered by is buffered by
HemoglobinHemoglobin

65. 65
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©2) Food products2) Food products
ªSauerkraut
ªYogurt
ªCitric acid in fruits

66. 66
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©3) Medications3) Medications
ªMay stimulate HClHCl
production by
parietal cells of the
stomach

67. 67
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©4) Metabolic 4) Metabolic
IntermediateIntermediate
by-productsby-products
ªLactic acid
ªPyruvic acid
ªAcetoacetic acid
ªFatty acids
CC
66HH
1212OO
66 2 C2 C
33HH
66OO
33

68. 68
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©Inorganic acids can also be produced
during breakdown of nutrients
ªProteinsProteins (meat products)
¨Breakdown leads to
productions of sulfuric
acid and phosphoric acid
ªFruitsFruits and VegetablesVegetables
¨Breakdown produces
bases which can help
to equalize acid
production

69. 69
SOURCES OF HYDROGEN IONS SOURCES OF HYDROGEN IONS
©5) Some disease processes5) Some disease processes
ªEx: diabetes causes improper
metabolism of fats which results in
the generation of a waste product
called a Keto AcidKeto Acid

70. 70
SOURCES OF SOURCES OF
BICARBONATE IONSBICARBONATE IONS

71. 71
SOURCES OF BICARBONATE IONSSOURCES OF BICARBONATE IONS
©1) CO1) CO
22 diffusion into red blood cells diffusion into red blood cells
©2) Parietal cell2) Parietal cell
secretion of thesecretion of the
gastric mucosagastric mucosa

72. 72
1) CO1) CO
2 2 DIFFUSIONDIFFUSION
©Hemoglobin buffers H
+
©Chloride shift insures electrical
neutrality
Hb
Cl
-
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
Cl
-
Cl
-
Cl
-
Cl
-
Cl
-
Cl
-
Red Blood Cell
Cl
-

73. 73
CARBON DIOXIDE DIFFUSIONCARBON DIOXIDE DIFFUSION
COCO
22
COCO
22
Red Blood CellRed Blood Cell Systemic CirculationSystemic Circulation
COCO
22HH
22OO HH
++
HCOHCO
33
--
++ ++
HCOHCO
33
--
ClCl
--
(Chloride Shift)(Chloride Shift)
COCO
22 diffuses into the plasma and into the RBC diffuses into the plasma and into the RBC
Within the RBC, the hydration of COWithin the RBC, the hydration of CO
22 is catalyzed is catalyzed
by carbonic anhydraseby carbonic anhydrase
Bicarbonate thus formed diffuses into plasmaBicarbonate thus formed diffuses into plasma
carboniccarbonic
anhydraseanhydrase
TissuesTissues
PlasmaPlasma

74. 74
BICARBONATE DIFFUSIONBICARBONATE DIFFUSION
Red Blood CellRed Blood Cell
Pulmonary CirculationPulmonary Circulation
COCO
22HH
22OO HH
++
HCOHCO
33
--
++ ++
HCOHCO
33
--
ClCl
--
AlveolusAlveolus
PlasmaPlasma
COCO
22
Bicarbonate diffuses back into RBC in pulmonary Bicarbonate diffuses back into RBC in pulmonary
capillaries and reacts with hydrogen ions to form capillaries and reacts with hydrogen ions to form
carbonic acidcarbonic acid
The acid breaks down to COThe acid breaks down to CO
2 2 and waterand water

75. 75
BICARBONATE DIFFUSIONBICARBONATE DIFFUSION
Red Blood CellRed Blood Cell
Pulmonary CirculationPulmonary Circulation
COCO
22HH
22OO
HH
++
++ ++
HCOHCO
33
--
ClCl
--
AlveolusAlveolus
PlasmaPlasma
COCO
22
COCO
22HH
22OO

76. 76
2) PARIETAL CELL SECRETION2) PARIETAL CELL SECRETION
©Bicarbonate ions
diffuse into the
bloodstream to
maintain electrical
neutrality in the
parietal cell
Blood Lumen of
Stomach
Parietal
Cells
H
+
Cl
-
HCO
3
-
HCl
Click to see ion
movement
CO
2
+ H
2
O
©Secrete hydrogen ions into the lumen of the
stomach

77. 77
PANCREATIC CELL SECRETIONPANCREATIC CELL SECRETION
Blood Pancreatic
duct
Pancreatic
Cells
H
+
HCO
3
-
Click to see ion
movement
©H
+
ions are
secreted into the
blood and
bicarbonate ions
diffuse into
pancreatic juice
©In pancreatic cells the direction of ion
movement is reversed
HCO
3
-

78. 78
PARIETAL CELL SECRETIONPARIETAL CELL SECRETION
©If the two processes are balanced, there is
no net change in the amount of bicarbonate
in blood
ªLoss of gastric or pancreatic juice can
change that balance
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-

79. 79
©Cells of the gastric
mucosa secrete H
+

ions into the lumen of
the stomach in
exchange for the
diffusion of
bicarbonate ions into
blood
©The direction of the
diffusion of these ions
is reversed in
pancreatic epithelial
cells
BICARBONATE SECRETIONBICARBONATE SECRETION
Parietal cells of
gastric mucosa
Pancreatic
epithelial cells
HCO
3
-
H
+
HCO
3
-
H
+
lumen of
stomach
pancreatic
juice
blood
blood

80. 80
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS

81. 81
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©Deviations from normal Acid-Base status
are divided into fourfour general categories,
depending on the source and direction of the
abnormal change in HH
++
concentrations
ªRespiratory AcidosisRespiratory Acidosis
ªRespiratory AlkalosisRespiratory Alkalosis
ªMetabolic AcidosisMetabolic Acidosis
ªMetabolic AlkalosisMetabolic Alkalosis

82. 82
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
©Acidosis and Alkalosis are categorized as
MetabolicMetabolic or RespiratoryRespiratory depending on
their primary cause
ªMetabolic AcidosisMetabolic Acidosis and and Metabolic Metabolic
AlkalosisAlkalosis
¨caused by an imbalance in the
production and excretion of acids or
bases by the kidneys
ªRespiratory Acidosis and Respiratory
Alkalosis
¨caused primarily by lung or breathing
disorders

83. 83
ACIDOSISACIDOSIS
©A pH of 7.4 corresponds to a 20:1 ratio of
HCO
3
-
and H
2
CO
3
ªConcentration of HCO
3
-
is 24 meq/liter and
H
2
CO
3
is 1.2 meq/liter
Bicarbonate
Carbonic Acid
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate
Bicarbonate7.4

84. 84
ACIDOSISACIDOSIS
©Acidosis is a decreasedecrease in pH below 7.35
ªWhich means a relative increase of HH
++

ions
ªpH may fall as low as 7.0 without
irreversible damage but any fall less than
7.0 is usually fatal
H
+
pH=

85. 85
ACIDOSIS ACIDOSIS
©May be caused by:
ªAn increase in H
2
CO
3
ªA decrease in HCO
3
-
©Both lead to a decrease in the ratio of
20:1
H
2
CO
3
HCO
3
-

86. 86
ACIDOSISACIDOSIS
©1) Respiratory Acidosis1) Respiratory Acidosis
©2) Metabolic Acidosis2) Metabolic Acidosis
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+ H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+

87. 87
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
©1) Respiratory alkalosis1) Respiratory alkalosis
©2) Metabolic alkalosis2) Metabolic alkalosis
ALKALOSISALKALOSIS

88. 88
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS

89. 89
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©Caused by hyperkapnia due to
hypoventilation
ªCharacterized by a pH decrease
and an increase in COCO
22
CO
2 CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
pH
pH

90. 90
HYPOVENTILATIONHYPOVENTILATION
©Hypo = “Under”
Elimination of CO
2
H
+
pH

91. 91
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©HyperkapniaHyperkapnia is defined as an
accumulation of carbon dioxide in
extracellular fluids
CO
2 CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
pH
pH

92. 92
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©Hyperkapnia is the underlying cause of
Respiratory AcidosisRespiratory Acidosis
ªUsually the result of decreased COCO
22

removal from the lungs
CO
2 CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
pH
pH

93. 93
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©The speed and depth of breathing control the
amount of COCO
22
in the blood
©Normally when COCO
22
builds up, the pHpH of the blood
falls and the blood becomes acidic
©High levels of COCO
22
in the blood stimulate the parts
of the brain that regulate breathing, which in turn
stimulate faster and deeper breathing

94. 94
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©Respiratory acidosis
develops when the lungs
don't expel COCO
22

adequately
©This can happen in
diseases that severely
affect the lungs, such as
emphysema, chronic
bronchitis, severe
pneumonia, pulmonary
edema, and asthma

95. 95
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©Respiratory acidosis can also develop when
diseases of the nerves or muscles of the chest
impair the mechanics of breathing
©In addition, a person can develop respiratory
acidosis if overly sedated from narcotics and
strong sleeping medications that slow respiration

96. 96
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©The treatment of respiratory acidosis aims
to improve the function of the lungs
©Drugs to improve breathing may help
people who have lung diseases such as
asthma and emphysema

97. 97
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©Decreased COCO
22
removal
can be the result of:
1)1)Obstruction of air Obstruction of air
passagespassages
2)2)Decreased respiration Decreased respiration
(depression of (depression of
respiratory centers)respiratory centers)
3)3)Decreased gas Decreased gas
exchange between exchange between
pulmonary capillaries pulmonary capillaries
and air sacs of lungsand air sacs of lungs
4)4)Collapse of lungCollapse of lung

98. 98
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©1) Obstruction of air passages1) Obstruction of air passages
ªVomit, anaphylaxis, tracheal cancer

99. 99
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©2) Decreased Respiration2) Decreased Respiration
ªShallow, slow breathing
ªDepression of the respiratory centers in the
brain which control breathing rates
¨Drug overdose

100. 100
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©3) Decreased 3) Decreased
gas exchange gas exchange
between between
pulmonary pulmonary
capillaries and capillaries and
air sacs of lungsair sacs of lungs
ªEmphysema
ªBronchitis
ªPulmonary
edema

101. 101
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
©4) Collapse of lung4) Collapse of lung
ªCompression injury, open thoracic Compression injury, open thoracic
woundwound
Left lung
collapsed

102. 102
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
-metabolic balance before onset of acidosis
-pH = 7.4
-respiratory acidosis
-pH = 7.1
-breathing is suppressed holding CO
2
in
body
-body’s compensation
-kidneys conserve HCO
3
-
ions to restore
the normal 40:2 ratio
-kidneys eliminate H
+
ion in acidic urine
- therapy required to restore metabolic
balance
- lactate solution used in therapy is
converted to bicarbonate ions in the liver
40

103. 103
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
- metabolic balance before onset of acidosis
- pH = 7.4
H
2
CO
3
HCO
3
-
1 20:
H
2
CO
3
: Carbonic Acid
HCO
3
-
: Bicarbonate Ion
(Na
+
) HCO
3
-
(K
+
) HCO
3
-
(Mg
++
) HCO
3
-
(Ca
++
) HCO
3
-

104. 104
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
-breathing is suppressed holding CO
2
in body
-pH = 7.1
H2
CO
3
HCO
3
-
2 20:
CO
2
CO
2
CO
2
CO
2

105. 105
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
BODY’S COMPENSATION
-kidneys conserve HCO
3
-
ions to restore the
normal 40:2 ratio (20:1)
-kidneys eliminate H
+
ion in acidic urine
H2
CO3
HCO 3
-
2 30:
HCO
3
-
H
2
CO
3
HCO
3
-
H
+
+
acidic urine

106. 106
RESPIRATORY ACIDOSISRESPIRATORY ACIDOSIS
- therapy required to restore metabolic balance
- lactate solution used in therapy is converted to
bicarbonate ions in the liver
H
2
CO
3
HCO
3
-
2 40:
Lactate
Lactate
LIVER
HCO
3
-

107. 107
RESPIRATORY RESPIRATORY
ALKALOSISALKALOSIS

108. 108
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Normal 20:1 ratio is increased
ªpH of blood is above 7.4
H
2
CO
3
HCO
3
-
1 20:
=7.4
H
2CO
3
HCO
3
-
0.5 20:
=7.4

109. 109
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Cause is Hyperventilation
ªLeads to eliminating excessive amounts
of COCO
22
ªIncreased loss of COCO
22
from the lungs at a
rate faster than it is produced
ªDecrease in HH
++
CO
2 CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2

110. 110
HYPERVENTILATIONHYPERVENTILATION
©Hyper = “Over”
Elimination of CO
2
H
+
pH

111. 111
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Can be the result of:
ª1) Anxiety, emotional
disturbances
ª2) Respiratory center
lesions
ª3) Fever
ª4) Salicylate poisoning
(overdose)
ª5) Assisted respiration
ª6) High altitude (low PO
2)

112. 112
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Anxiety is an emotional
disturbance
©The most common cause
of hyperventilation, and
thus respiratory alkalosis,
is anxiety

113. 113
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Usually the only treatment needed is to slow
down the rate of breathing
©Breathing into a paper bag or holding the
breath as long as possible may help raise
the blood COCO
22
content as the person
breathes carbon dioxide
back in after breathing it out

114. 114
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Respiratory center Respiratory center
lesionslesions
ªDamage to brain Damage to brain
centers responsible centers responsible
for monitoring for monitoring
breathing ratesbreathing rates
¨TumorsTumors
¨StrokesStrokes

115. 115
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©FFeverever
ªRapid shallow Rapid shallow
breathing blows off breathing blows off
too much too much COCO
22

116. 116
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Salicylate poisoning Salicylate poisoning
(Aspirin overdose)(Aspirin overdose)
ªVentilation is stimulated Ventilation is stimulated
without regard to the without regard to the
status of status of OO
22, , COCO
22 or or HH
++
in in
the body fluidsthe body fluids

117. 117
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Assisted RespirationAssisted Respiration
ªAdministration of Administration of COCO
22 in the exhaled air in the exhaled air
of the care - giverof the care - giver
Your insurance won’t cover a
ventilator any longer, so Bob
here will be giving you mouth
to mouth for the next several
days

118. 118
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©High AltitudeHigh Altitude
ªLow concentrations of Low concentrations of OO
2 2 in the arterial blood in the arterial blood
reflexly stimulates ventilation in an attempt to reflexly stimulates ventilation in an attempt to
obtain moreobtain more O O
22
ªToo much Too much COCO
22 is “blown off” in the process is “blown off” in the process

119. 119
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Kidneys compensate by:
ªRetaining hydrogen ionsRetaining hydrogen ions
ªIncreasing bicarbonate excretionIncreasing bicarbonate excretion
H
+
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
HCO
3
-
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+

120. 120
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
©Decreased COCO
22
in the lungs will
eventually slow the rate of breathing
ªWill permit a normal amount of COCO
22

to be retained in the lung

121. 121
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
-metabolic balance before onset of
alkalosis
-pH = 7.4
-respiratory alkalosis
-pH = 7.7
- hyperactive breathing “ blows off ” CO
2
- body’s compensation
- kidneys conserve H
+
ions and eliminate
HCO
3
-
in alkaline urine
- therapy required to restore metabolic
balance
- HCO
3
-
ions replaced by Cl
-
ions

122. 122
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
-metabolic balance before onset of alkalosis
-pH = 7.4
H
2
CO
3
HCO
3
-
1 20:
H
2
CO
3
: Carbonic Acid
HCO
3
-
: Bicarbonate Ion
(Na
+
) HCO
3
-
(K
+
) HCO
3
-
(Mg
++
) HCO
3
-
(Ca
++
) HCO
3
-

123. 123
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
-respiratory alkalosis
-pH = 7.7
-hyperactive breathing “ blows off ” CO
2
H
2CO
3
HCO
3
-
0.5 20:
CO
2
CO
2+ H
2
O

124. 124
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
BODY’S COMPENSATION
- kidneys conserve H
+
ions and eliminate HCO
3
-
in
alkaline urine
H
2CO
3 HCO
3
-
0.5 15:
HCO
3
-
Alkaline Urine

125. 125
RESPIRATORY ALKALOSISRESPIRATORY ALKALOSIS
- therapy required to restore metabolic balance
- HCO
3
-
ions replaced by Cl
-
ions
H
2
CO
3
HCO
3
-
0.5 10:
Cl
-
Chloride
containing
solution

126. 126
RESPIRATORYRESPIRATORY
ACIDOSIS / ALKALOSISACIDOSIS / ALKALOSIS
COCO
22 + H + H
22OO HH
22COCO
33
HH
++
+ HCO + HCO
33
--

Respiratory Acidosis
Respiratory Alkalosis

127. 127
METABOLIC ACIDOSISMETABOLIC ACIDOSIS

128. 128
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Occurs when there is a decrease in the
normal 20:1 ratio
ªDecrease in blood pHpH and bicarbonate
level
©Excessive HH
++
or decreased HCOHCO
33
--
H
2
CO
3
HCO
3
-
1 20:
=7.4
H2
CO3
HCO
3
-
1 10:
=7.4

129. 129
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Any acid-base
imbalance not
attributable to COCO
22
is
classified as metabolic
ªMetabolic production
of AcidsAcids
ªOr loss of BasesBases

130. 130
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©If an increase in acid overwhelms the body's
pHpH buffering system, the blood can become
acidic
©As the blood pHpH drops,
breathing becomes
deeper and faster as the
body attempts to rid the
blood of excess acid by
decreasing the amount
of carbon dioxide

131. 131
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Eventually, the kidneys
also try to compensate by
excreting more acid in the
urine
©However, both
mechanisms can be
overwhelmed if the body
continues to produce too
much acid, leading to
severe acidosis and
eventually a coma

132. 132
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Metabolic acidosis is always characterized
by a reduction in plasma HCOHCO
33
--
while COCO
22

remains normal
HCO
3
-
CO
2
Plasma Levels

133. 133
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Acidosis results from excessive loss of HCOHCO
33
--

rich fluids from the body or from an
accumulation of acids
ªAccumulation of non-carbonic plasma acids
uses HCOHCO
33
--
as a buffer for the additional HH
++

thus reducing HCOHCO
33
--
levels
Lactic Acid
Muscle Cell

134. 134
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©The causes of metabolic acidosis can be
grouped into fivefive major categories
ª1)1) Ingesting an acid or a substance that
is metabolized to acid
ª2) Abnormal Metabolism2) Abnormal Metabolism
ª3) Kidney Insufficiencies3) Kidney Insufficiencies
ª4) Strenuous Exercise4) Strenuous Exercise
ª5) Severe Diarrhea5) Severe Diarrhea

135. 135
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©1) Ingesting An Acid1) Ingesting An Acid
ªMost substances that cause acidosis when
ingested are considered poisonous
ªExamples include
wood alcohol
(methanol) and
antifreeze
(ethylene glycol)
ªHowever, even an overdose
of aspirin (acetylsalicylic acid)
can cause metabolic acidosis

136. 136
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©2) Abnormal Metabolism2) Abnormal Metabolism
ªThe body can produce excess acid as a
result of several diseases
¨One of the most significant is Type I
Diabetes Mellitus

137. 137
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Unregulated diabetes
mellitus causes
ketoacidosisketoacidosis
ªBody metabolizes
fat rather than
glucose
ªAccumulations of
metabolic acids
(Keto Acids)(Keto Acids) cause
an increase in
plasma HH
++

138. 138
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©This leads to excessive production of
ketones:ketones:
ªAcetoneAcetone
ªAcetoacetic acidAcetoacetic acid
ªB-hydroxybutyric acidB-hydroxybutyric acid
©Contribute excessive numbers of hydrogen
ions to body fluids
Acetone
Acetoacetic acid
Hydroxybutyric acid
H
+
H
+
H
+
H
+
H
+
H
+
H
+

139. 139
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©2) Abnormal Metabolism2) Abnormal Metabolism
ªThe body also produces excess acid in
the advanced stages of shock, when lactic
acid is formed through the metabolism of
sugar

140. 140
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©3) Kidney Insufficiencies3) Kidney Insufficiencies
ªEven the production of
normal amounts of acid
may lead to acidosis
when the kidneys aren't
functioning normally

141. 141
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©3) Kidney Insufficiencies3) Kidney Insufficiencies
ªKidneys may be unable to
rid the plasma of even the
normal amounts of HH
++

generated from metabolic
acids
ªKidneys may be also
unable to conserve an
adequate amount of HCOHCO
33
--

to buffer the normal acid
load

142. 142
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©3) Kidney Insufficiencies3) Kidney Insufficiencies
ªThis type of kidney malfunction is called
renal tubular acidosisrenal tubular acidosis or uremic uremic
acidosisacidosis and may occur in people with
kidney failure or with abnormalities that
affect the kidneys' ability to excrete acid

143. 143
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©4) Strenuous Exercise4) Strenuous Exercise
ªMuscles resort to anaerobic glycolysis
during strenuous exercise
ªAnaerobic respiration leads to the
production of large amounts of lactic acid
C
6H
12O
6 2C
3H
6O
3 + ATP (energy)
Enzymes
Lactic Acid

144. 144
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©5) Severe Diarrhea5) Severe Diarrhea
ªFluids rich in HCOHCO
33
--
are released and
reabsorbed during the digestive process
ªDuring diarrhea this HCOHCO
33
--
is lost from the
body rather than reabsorbed

145. 145
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©5) Severe Diarrhea5) Severe Diarrhea
ªThe loss of HCOHCO
33
--
without a corresponding
loss of H
+
lowers the pH
ªLess HCOHCO
33
--
is available for buffering HH
++
ªProlonged deep (from duodenum) vomiting
can result in the same situation

146. 146
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Treating the underlying cause of metabolic
acidosis is the usual course of action
ªFor example, they may control diabetes with
insulin or treat poisoning by removing the
toxic substance
from the blood
ªOccasionally
dialysis is needed
to treat severe
overdoses and
poisonings

147. 147
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©Metabolic acidosis may also
be treated directly
ªIf the acidosis is mild,
intravenous fluids and
treatment for the
underlying disorder may be
all that's needed

148. 148
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
©When acidosis is severe,
bicarbonate may be given
intravenously
ªBicarbonate provides
only temporary relief and
may cause harm

149. 149
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
- metabolic balance before onset of
acidosis
- pH 7.4
- metabolic acidosis
- pH 7.1
- HCO
3
-
decreases because of excess
presence of ketones, chloride or organic
ions
- body’s compensation
- hyperactive breathing to “ blow off ”
CO
2
- kidneys conserve HCO
3
-
and eliminate
H
+
ions in acidic urine
- therapy required to restore metabolic
balance
- lactate solution used in therapy is
converted to bicarbonate ions
in the liver
0.5 10

150. 150
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
-metabolic balance before onset of acidosis
-pH 7.4
H
2
CO
3
: Carbonic Acid
HCO
3
-
: Bicarbonate Ion
(Na
+
) HCO
3
-
(K
+
) HCO
3
-
(Mg
++
) HCO
3
-
(Ca
++
) HCO
3
-
H
2
CO
3
HCO
3
-
1 20:

151. 151
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
-HCO
3
-
decreases because of excess presence of
ketones, chloride or organic ions
-pH 7.1
H2
CO3
HCO
3
-
1 10:
=7.4

152. 152
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
BODY’S COMPENSATION
- hyperactive breathing to “ blow off ” CO
2
- kidneys conserve HCO
3
-
and eliminate H
+
ions in
acidic urine
H2
CO3
HCO
3
-
0.75 10:
CO
2
COCO
22+ H+ H
22OO
HCO
3
-
+ H
+
HCOHCO
33
--
++
HH
++
Acidic urine

153. 153
METABOLIC ACIDOSISMETABOLIC ACIDOSIS
- therapy required to restore metabolic balance
- lactate solution used in therapy is converted to
bicarbonate ions in the liver
H
2
CO
3
HCO
3
-
0.5 10:
Lactate
Lactate
containing
solution

154. 154
METABOLIC ALKALOSISMETABOLIC ALKALOSIS

155. 155
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Elevation of pHpH due to an increased 20:1
ratio
ªMay be caused by:
¨An increase of bicarbonate
¨A decrease in hydrogen ions
ªImbalance again cannot be due to COCO
22
ªIncrease in pHpH which has a non-
respiratory origin
7.4

156. 156
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©A reduction in HH
++
in the case of metabolic
alkalosis can be caused by a deficiency of
non-carbonic acids
©This is associated with an increase in HCOHCO
33
--

157. 157
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Treatment of metabolic alkalosis is most
often accomplished by replacing water and
electrolytes (sodiumsodium and potassiumpotassium) while
treating the underlying cause
©Occasionally when metabolic alkalosis is
very severe, dilute acid in the form of
ammonium chloride is given by IV

158. 158
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Can be the result of:
ª1) Ingestion of Alkaline Substances1) Ingestion of Alkaline Substances
ª2) Vomiting ( loss of HCl )2) Vomiting ( loss of HCl )

159. 159
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©1) Ingestion of Alkaline Substances1) Ingestion of Alkaline Substances
ªInflux of NaHCONaHCO
33

160. 160
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Baking soda (NaHCONaHCO
33
) often used as a
remedy for gastric hyperacidity
ªNaHCONaHCO
33
dissociates to NaNa
++
and HCOHCO
33
--

161. 161
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Bicarbonate neutralizes high
acidity in stomach (heart burn)
©The extra bicarbonate is
absorbed into the plasma
increasing pHpH of plasma as
bicarbonate binds with free HH
++

162. 162
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Commercially prepared alkaline products for
gastric hyperacidity are not absorbed from
the digestive tract and do not alter the pHpH
status of the plasma

163. 163
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©2) Vomiting (abnormal loss of HCl)2) Vomiting (abnormal loss of HCl)
ªExcessive loss of H
+

164. 164
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
©Gastric juices contain large amounts of HClHCl
©During HClHCl secretion, bicarbonate is added to
the plasma
K
+ H
+
Cl
-
HCO
3
-
HCl
Click to
View Animation

165. 165
HCl
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
K
+
H
+
Cl
-
HCO
3
-
Click to
View Animation
©The bicarbonate is neutralized as HClHCl is
reabsorbed by the plasma from the digestive
tract
H
2
CO
3

166. 166
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
HCl
K
+
HCO
3
-
Click to
View Animation
©During vomiting HH
++
is lost as HClHCl and the
bicarbonate is not neutralized in the plasma
ªLoss of HClHCl increases the plasma bicarbonate
and thus results in an increase in pHpH of the
blood
Bicarbonate not Bicarbonate not
neutralizedneutralized

167. 167
METABOLIC ALKALOSIS METABOLIC ALKALOSIS
©Reaction of the body to alkalosis is to lower
pHpH by:
ªRetain CO
2
by decreasing breathing rate
ªKidneys increase the retention of HH
++
CO
2
CO
2
H
+
H
+
H
+
H
+

168. 168
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
- metabolic balance before onset of
alkalosis
- pH = 7.4
- metabolic alkalosis
- pH = 7.7
- HCO
3
-
increases because of loss of
chloride ions or excess ingestion of
NaHCO
3
- body’s compensation
- breathing suppressed to hold CO
2
- kidneys conserve H
+
ions and eliminate
HCO
3
-
in alkaline urine
- therapy required to restore metabolic
balance
- HCO
3
-
ions replaced by Cl
-
ions1.25 25

169. 169
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
- metabolic balance before onset of alkalosis
- pH = 7.4
H
2
CO
3
: Carbonic Acid
HCO
3
-
: Bicarbonate Ion
(Na
+
) HCO
3
-
(K
+
) HCO
3
-
(Mg
++
) HCO
3
-
(Ca
++
) HCO
3
-
H
2
CO
3
HCO
3
-
1 20:

170. 170
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
- pH = 7.7
- HCO
3
-
increases because of loss of chloride ions
or excess ingestion of NaHCO
3
HCO
3
-
1 40:
H
2CO
3

171. 171
H
2CO
3
HCO
3
-
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
BODY’S COMPENSATION
- breathing suppressed to hold CO
2
- kidneys conserve H
+
ions and eliminate HCO
3
-
in
alkaline urine
1.25 30
CO
2
+ H
2
O
HCO
3
-
+ H
+
HCO
3
-
H
+
+
Alkaline urine
:

172. 172
METABOLIC ALKALOSISMETABOLIC ALKALOSIS
- Therapy required to restore metabolic balance
- HCO
3
-
ions replaced by Cl
-
ions
H
2
CO
3
HCO
3
-
1.25 25:
Cl
-
Chloride
containing
solution

173. 173
ACIDOSISACIDOSIS
decreased
removal of
CO
2
from
lungs
failure of
kidneys to
excrete
acids
metabolic
acid
production
of keto acids
absorption of
metabolic acids
from GI tract
prolonged
diarrhea
accumulation
of CO
2
in blood
accumulation
of acid in blood
excessive loss
of NaHCO
3

from blood
metabolic
acidosis
deep
vomiting
from
GI tract
kidney
disease
(uremia)
increase in
plasma H
+
concentration
depression of
nervous system
accumulation
of CO
2
in blood
accumulation
of acid in blood
excessive loss
of NaHCO
3

from blood
respiratory
acidosis

174. 174
ALKALOSISALKALOSIS
respiratory
alkalosis
anxiety overdose
of certain
drugs
high
altitudes
prolonged
vomiting
ingestion of
excessive
alkaline drugs
excess
aldosterone
hyperventilation
loss of CO
2
and
H
2
CO
2
from
blood
loss of acid accumulation
of base
metabolic
alkalosis
decrease
in plasma H
+
concentration
overexcitability
of nervous
system
hyperventilation
loss of CO
2
and
H
2
CO
2
from
blood
loss of acid accumulation
of base

175. 175
ACID – BASE DISORDERSACID – BASE DISORDERS
Clinical State Acid-Base Disorder
Pulmonary Embolus Respiratory Alkalosis
Cirrhosis Respiratory Alkalosis
Pregnancy Respiratory Alkalosis
Diuretic Use Metabolic Alkalosis
Vomiting Metabolic Alkalosis
Chronic Obstructive Pulmonary Disease Respiratory Acidosis
Shock Metabolic Acidosis
Severe Diarrhea Metabolic Acidosis
Renal Failure Metabolic Acidosis
Sepsis (Bloodstream Infection)
Respiratory Alkalosis,
Metabolic Acidosis

176. 176
RESPONSES TO:RESPONSES TO:
ACIDOSIS AND ALKALOSISACIDOSIS AND ALKALOSIS
©Mechanisms protect the body against life-
threatening changes in hydrogen ion
concentration
ª1) Buffering Systems in Body Fluids1) Buffering Systems in Body Fluids
ª2) Respiratory Responses2) Respiratory Responses
ª3) Renal Responses3) Renal Responses
ª4) Intracellular Shifts of Ions4) Intracellular Shifts of Ions

177. 177
• Buffer SystemsBuffer Systems
2) Respiratory Responses2) Respiratory Responses
3) Renal Responses3) Renal Responses
4) Intracellular Shifts of Ions4) Intracellular Shifts of Ions

178. 178
BUFFERSBUFFERS
©Buffering systems provide an immediate
response to fluctuations in pHpH
ª1) Phosphate1) Phosphate
ª2) Protein2) Protein
ª3) Bicarbonate Buffer System3) Bicarbonate Buffer System

179. 179
BUFFERSBUFFERS
©A buffer is a combination of chemicals in
solution that resists any significant change in
pHpH
©Able to bind or release free HH
++
ions

180. 180
BUFFERSBUFFERS
©Chemical buffers are able to react
immediately (within milliseconds)
©Chemical buffers are the first line of defense
for the body for fluctuations in pHpH

181. 181
©1) Phosphate buffer system1) Phosphate buffer system
Na
2
HPO
4
+ H
+
NaH
2
PO
4

+ Na
+

ªMost important in the intracellular system
PHOSPHATE BUFFER SYSTEMPHOSPHATE BUFFER SYSTEM
H
+
Na
2
HPO
4
+
NaH
2
PO
4
Click to
animate
Na
+
+

182. 182
Na
2
HPO
4
+ H
+
NaH
2
PO
4

+ Na
+
©Alternately switches NaNa
++
with HH
++
PHOSPHATE BUFFER SYSTEMPHOSPHATE BUFFER SYSTEM
H
+
Na
2
HPO
4
+
NaH
2
PO
4
Click to
animate
Na
+
+
Disodium hydrogen phosphate

183. 183
Na
2
HPO
4
+ H
+
NaH
2
PO
4

+ Na
+
©Phosphates are more abundant within the
cell and are rivaled as a buffer in the ICF by
even more abundant protein
PHOSPHATE BUFFER SYSTEMPHOSPHATE BUFFER SYSTEM
Na
2
HPO
4
Na
2
HPO
4
Na
2
HPO
4

184. 184
©Regulates pHpH within the cells and the urine
ªPhosphate concentrations are higher
intracellularly and within the kidney
tubules
ªToo low of a
concentration in
extracellular fluid
to have much
importance as an
ECFECF buffer system
PHOSPHATE BUFFER SYSTEMPHOSPHATE BUFFER SYSTEM
HPO
4
-2

185. 185
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©2) Protein Buffer System2) Protein Buffer System
ªBehaves as a buffer in both plasma and
cells
ªHemoglobin is by far the most important
protein buffer

186. 186
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Most important
intracellular buffer
(ICFICF)
©The most plentiful
buffer of the body

187. 187
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Proteins are excellent buffers because they
contain both acid and base groups that can
give up or take up HH
++
©Proteins are extremely abundant in the cell
©The more limited number of proteins in the
plasma reinforce the bicarbonate system in
the ECFECF

188. 188
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Hemoglobin buffers HH
++
from metabolically
produced COCO
22
in the plasma only
©As hemoglobin releases OO
22
it gains a great
affinity for HH
++

HbHb
O
2
O
2
O
2
O
2
H
+

189. 189
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©HH
++
generated at the tissue level from the
dissociation of HH
22COCO
33
produced by the
addition of COCO
22
©Bound HH
++
to Hb Hb (Hemoglobin) does not
contribute to the acidity of blood
HbHb
O
2
O
2
O
2
O
2
H
+

190. 190
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©As HH
++
HbHb picks up OO
22
from the lungs the HbHb
which has a higher affinity for OO
22
releases HH
++

and picks up OO
22
©Liberated HH
++
from HH
22OO combines with HCOHCO
33
--
HCOHCO
33
--
HH
22COCO
33
COCO
22
(exhaled)
HbHb
O
2
O
2
O
2
H
+
O
2

191. 191
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Venous blood is only slightly more acidic
than arterial blood because of the
tremendous buffering capacity of HbHb
©Even in spite of the large volume of HH
++

generating COCO
22
carried in venous blood

192. 192
Pr
-
added H
+
+ Pr
-
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Proteins can act as a buffer for both acids
and bases
©Protein buffer system works instantaneously
making it the most powerful in the body
©75% of the body’s buffer capacity is
controlled by protein
ªBicarbonate and phosphate buffer
systems require several hours to be
effective

193. 193
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©Proteins are very large, complex molecules
in comparison to the size and complexities
of acids or bases
©Proteins are surrounded by a multitude of
negative charges on the outside and
numerous positive charges in the crevices of
the molecule
-
-
-
----
-
-
-
-
-
-
-
--
-----
-
---
-
-
-
-
- --
-
+
+
++
+
+
+
+
+
+
+
+
+
++
+
+
+
+
+
+
+
+
+
+

194. 194
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©H
+
ions are attracted to and held from
chemical interaction by the negative charges
-
-
-
----
-
-
-
-
-
-
-
--
-----
-
---
-
-
-
-
- --
-
+
+
++
+
+
+
+
+
+
+
+
+
++
+
+
+
+
+
+
+
+
+
+
H
+
H
+
H
+
H
+ H
+ H
+ H
+ H
+ H
+ H
+
H
+
H
+
H
+
H
+
H
+H
+
H
+
H
+
H
+
H
+
H
+

195. 195
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
©OH
-
ions which are the basis of alkalosis are
attracted by the positive charges in the
crevices of the protein
-
-
-
----
-
-
-
-
-
-
-
--
-----
-
---
-
-
-
-
- --
-
+
+
++
+
+
+
+
+
+
+
+
+
++
+
+
+
+
+
+
+
+
+
+
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-

196. 196
PROTEIN BUFFER SYSTEMPROTEIN BUFFER SYSTEM
-
-
-
----
-
-
-
-
-
-
-
--
-----
-
---
-
-
-
-
- --
-
+
+
++
+
+
+
+
+
+
+
+
+
++
+
+
+
+
+
+
+
+
+
+
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
OH
-
H
+
H
+
H
+
H
+ H
+ H
+ H
+ H
+ H
+ H
+
H
+
H
+
H
+
H
+
H
+H
+
H
+
H
+
H
+
H
+
H
+

197. 197
BICARBONATE BUFFER SYSTEMBICARBONATE BUFFER SYSTEM
©3) Bicarbonate Buffer System3) Bicarbonate Buffer System
ªPredominates in extracellular fluid (ECFECF)
HCOHCO
33
- -
+ added H+ added H
++
H H
22COCO
33
HCOHCO
33
--
HH
22COCO
33

198. 198
BICARBONATE BUFFER SYSTEMBICARBONATE BUFFER SYSTEM
©This system is most important because the
concentration of both components can be
regulated:
ªCarbonic acidCarbonic acid by the respiratory system
ªBicarbonateBicarbonate by the renal system

199. 199
BICARBONATE BUFFER SYSTEMBICARBONATE BUFFER SYSTEM
©HH
22COCO
33
HH
++
+ HCO + HCO
33
--
ªHydrogen ions generated by metabolism or
by ingestion react with bicarbonate base to
form more carbonic acid
HCOHCO
33
--HH
22COCO
33

200. 200
BICARBONATE BUFFER SYSTEMBICARBONATE BUFFER SYSTEM
©Equilibrium shifts toward the formation of acid
ªHydrogen ions that are lost (vomiting) causes
carbonic acid to dissociate yielding
replacement HH
++
and bicarbonate
HH
++ HCOHCO
33
--
HH
22COCO
33

201. 201
Loss of HCl
Addition of lactic acid
BICARBONATE BUFFER SYSTEMBICARBONATE BUFFER SYSTEM
HH
++
HCOHCO
33
--
HH
22COCO
33HH
22OOCOCO
22+ ++
Exercise
Vomiting

202. 202
1) Buffer Systems1) Buffer Systems
2) Respiratory Responses2) Respiratory Responses
3) Renal Responses3) Renal Responses
4) Intracellular Shifts of Ions4) Intracellular Shifts of Ions

203. 203
RESPIRATORY RESPONSERESPIRATORY RESPONSE
©Neurons in the medulla oblongata and pons
constitute the Respiratory CenterRespiratory Center
©Stimulation and limitation of respiratory
rates are controlled by the respiratory center
©Control is
accomplished by
responding to CO
2
and H
+
concentrations in
the blood

204. 204
RESPIRATORY RESPIRATORY
CENTERCENTER
Respiratory centers
Medulla oblongata
Pons

205. 205
CHEMOSENSITIVE AREASCHEMOSENSITIVE AREAS
©Chemosensitive areas of the respiratory
center are able to detect blood concentration
levels of CO
2
and H
+
©Increases in CO
2 and H
+
stimulate the
respiratory center
ªThe effect is to raise
respiration rates
¨But the effect
diminishes in
1 - 2 minutes
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
Click to increase CO
2

206. 206
CHEMOSENSITIVE AREASCHEMOSENSITIVE AREAS
©The effect of
stimulating the
respiratory centers by
increased CO
2
and H
+

is weakened in
environmentally
increased CO
2
levels
©Symptoms may persist
for several days

207. 207
CHEMORECEPTORSCHEMORECEPTORS
©Chemoreceptors are also present in the
carotidcarotid and aorticaortic arteries which respond to
changes in partial pressures of O
2
and CO
2
or pH
©Increased levels of
CO
2
(low pHpH) or
decreased levels of
O
2
stimulate
respiration rates
to increase

208. 208
CHEMORECEPTORSCHEMORECEPTORS
©Overall compensatory response is:
ªHyperventilationHyperventilation in response to
increased CO
2
or H
+
(low pHpH)
ªHypoventilationHypoventilation in response to
decreased CO
2
or H
+
(high pHpH)

209. 209
RESPIRATORY CONTROL OF pHRESPIRATORY CONTROL OF pH
pH rises toward normal
rate and depth of breathing increase
CO
2
eliminated in lungs
H
+
stimulates respiratory center in medulla oblongata
H
2
CO
3
H
+
+ HCO
3
-

H
+
acidosis; pH drops
CO
2
+ H
2
O H
2
CO
3
cell production of CO
2
increases

210. 210
1) 1) Buffer SystemsBuffer Systems
2) Respiratory Responses2) Respiratory Responses
3) Renal Responses3) Renal Responses
4) Intracellular Shifts of Ions4) Intracellular Shifts of Ions

211. 211
RENAL RESPONSERENAL RESPONSE
©The kidney compensates for Acid - BaseAcid - Base
imbalance within 24 hours and is
responsible for long term control
©The kidney in response:
ªTo AcidosisTo Acidosis
¨Retains bicarbonate ions and
eliminates hydrogen ions
ªTo AlkalosisTo Alkalosis
¨Eliminates bicarbonate ions and
retains hydrogen ions

212. 212
ACIDIFICATION ACIDIFICATION
OF URINE BY OF URINE BY
EXCRETION OF EXCRETION OF
AMMONIAAMMONIA

213. 213
ACIDIFICATION OF URINE BY EXCRETION OF AMMONIAACIDIFICATION OF URINE BY EXCRETION OF AMMONIA
Capillary Distal Tubule Cells
Tubular urine
to be excreted
NH
2
H
+
NH
3
NH
2
H
+
NH
3
WHAT
HAPPENS
NEXT?

214. 214
Capillary Distal Tubule Cells
Tubular Urine
NH
3
Na
+
Cl
-
+
H
2
CO
3HCO
3
-
+
NaCl
NaHCO
3
Click Mouse to
Start Animation
NaHCO
3
NH
3
Cl
-
H
+
NH
4
Cl
Click Mouse to See
Animation Again
Notice the
H
+
- Na
+

exchange to
maintain
electrical
neutrality
ACIDIFICATION OF URINE BY EXCRETION OF AMMONIAACIDIFICATION OF URINE BY EXCRETION OF AMMONIA
Dissociation of
carbonic acid

215. 215
Capillary Distal Tubule Cells
Tubular Urine
NH
3
Na
+
Cl
-
+
H
2
CO
3HCO
3
-
+
NaCl
NaHCO
3
Click Mouse to
Start Animation
NaHCO
3
NH
3
Cl
-
H
+
NH
4
Cl
Click Mouse to See
Animation Again
Notice the
H
+
- Na
+

exchange to
maintain
electrical
neutrality
ACIDIFICATION OF URINE BY EXCRETION OF AMMONIAACIDIFICATION OF URINE BY EXCRETION OF AMMONIA

216. 216
RESPIRATORY / EXCRETORY RESPIRATORY / EXCRETORY
RESPONSERESPONSE
COCO
22 + H + H
22O HO H
22COCO
33 H H
++
+ HCO + HCO
33
--
Hyperventilation removes
HH
++
ion concentrations
Hypoventilation increases
HH
++
ion concentrations
Kidneys eliminate or retain
HH
++
or bicarbonate ions

217. 217
1) 1) Buffer SystemsBuffer Systems
2) Respiratory Responses2) Respiratory Responses
3) Renal Responses3) Renal Responses
4) Intracellular Shifts of Ions4) Intracellular Shifts of Ions

218. 218
HYPERKALEMIAHYPERKALEMIA
©HyperkalemiaHyperkalemia is generally associated with
acidosis
ªAccompanied by a shift of H
+
ions into
cells and K
+
ions out of the cell to maintain
electrical neutrality
H
+
K
+

219. 219
HYPERKALEMIAHYPERKALEMIA
©Hyperkalemia is an elevated serum K
+
ªH
+
ions are buffered in cell by proteins
©Acidosis may cause Hyperkalemia and
Hyperkalemia may cause Acidosis
H
+
K
+

220. 220
HYPOKALEMIAHYPOKALEMIA
©HypokalemiaHypokalemia is generally associated with
reciprocal exchanges of H
+
and K
+
in the
opposite direction
ªAssociated with alkalosis
©Hypokalemia is a depressed serum K
+
H
+
K
+

221. 221
ELECTROLYTE SHIFTSELECTROLYTE SHIFTS
cell
HH
++
KK
++
AcidosisAcidosis
Compensatory Response Result
- HH
++
buffered intracellularly
- Hyperkalemia
HH
++
KK
++
cell
AlkalosisAlkalosis
Compensatory Response Result
- Tendency to correct alkalosis
- Hypokalemia

222. 222
ENDEND
ACID - BASE BALANCEACID - BASE BALANCE