Metabolisme Asam-Basa kesehatan manusia.ppt

Asam basa

1. KESEIMBANGAN KESEIMBANGAN
ASAM-BASA (1)ASAM-BASA (1)
SudarnoSudarno, dr M, dr M.Kes..Kes.

2. 
KESEIMBANGAN ASAM-BASA merupakan bagian yang penting untuk KESEIMBANGAN ASAM-BASA merupakan bagian yang penting untuk
mempertahankan mekanisme mempertahankan mekanisme HOMEOSTATIKHOMEOSTATIK tubuhtubuh

Tanpa keseimbangan Asam-Basa sel tidak dapat berfungsiTanpa keseimbangan Asam-Basa sel tidak dapat berfungsi

Asam dan Basa secara kontinu masuk dalam peredaran darah berasal Asam dan Basa secara kontinu masuk dalam peredaran darah berasal
dari:dari:

Makanan Makanan  diet tinggi protein (daging,ikan,telur dll): ASAM diet tinggi protein (daging,ikan,telur dll): ASAM
diet tinggi sayuran/buah : BASAdiet tinggi sayuran/buah : BASA
-
Metabolisme Metabolisme  karbohidrat, lemak, proteinAsam BasaAsam karbohidrat, lemak, proteinAsam BasaAsam
Walaupun Asam-Basa merupakan komponen yang penting dalamWalaupun Asam-Basa merupakan komponen yang penting dalam
keseimbangan namunkeseimbangan namun KONSENTRASI dan PENGENDALIAN ion KONSENTRASI dan PENGENDALIAN ion
HIDROGEN (HHIDROGEN (H
++
)) yang akan dibahas pada keseimbangan Asam-Basayang akan dibahas pada keseimbangan Asam-Basa

3. The body produces more acids than
bases
Acids take in with foods
Acids produced by metabolism of lipids and
proteins
Cellular metabolism produces CO
2.
CO
2 + H
20 ↔ H
2CO
3 ↔ H
+
+ HCO
3
-

4. Ion HIDROGENIon HIDROGEN yang masuk dlm cairan tubuh yang masuk dlm cairan tubuh
berasal dari:berasal dari:

Asam KARBONAT (H2CO3) + LAKTAT Asam KARBONAT (H2CO3) + LAKTAT 
metabolisme aerobik dan anaerobik GLUKOSAmetabolisme aerobik dan anaerobik GLUKOSA

Asam SULFAT Asam SULFAT  metabolisme ASAM AMINO metabolisme ASAM AMINO

Asam FOSFATAsam FOSFAT metabolisme metabolisme
Ribonukleotida/fosfoproteinRibonukleotida/fosfoprotein

Asam KETON (ketone bodies) Asam KETON (ketone bodies)  metabolisme metabolisme
lemaklemak

5. Overview of Acid-Base PhysiologyOverview of Acid-Base Physiology

Volatile acids:
Fixed Acids:

7. AcidAcid
A proton donor
HOH + HCl (aq) Cl + H2O
acid base conjugate acid conjugate base
BaseBase
A proton acceptor

HCL + NaOH (aq) NaCl + H2O
BrØnsted-Lowry Definition
+ClH
H
H
O
+
H
H
HO Cl+

8. 
AcidAcid is a is a proton donorproton donor.
  It can be
.
  It can be
neutral, cationic, neutral, cationic,
or anionic.or anionic.

Molecules containing hydrogen atoms that can Molecules containing hydrogen atoms that can
releaserelease hydrogen hydrogen ions in solutions are referred to ions in solutions are referred to
as an as an acid.acid.

An example of an acid is hydrochloric acid (An example of an acid is hydrochloric acid (HHCLCL))
Acid-Base Balance
Arrhenius Definition
HCl (aq) H
+
+ Cl
-

9. 
Base is a Base is a proton acceptorproton acceptor.
  It can be
.
  It can be
neutral, neutral,
cationic, or anionic.cationic, or anionic.

A base is an ion that can A base is an ion that can acceptaccept a hydrogen ion. a hydrogen ion.

An example of a base is is the bicarbonate ion. An example of a base is is the bicarbonate ion.
( ( HCO3HCO3
--
))

When an When an acidacid releases a proton, it is converted to the releases a proton, it is converted to the
conjugate conjugate basebase. .

When a When a basebase binds a proton, it is converted to the binds a proton, it is converted to the
conjugate conjugate acidacid. .

Some substances can be either an Some substances can be either an acidacid or a or a basebase
depending on the environment.
  (i.e.,
depending on the environment.
  (i.e.,
H2PO4-H2PO4-))
Acid-Base Balance

10. Acids are H
+
donors.
Bases are H
+
acceptors, or give up OH
-
in
solution.
Acids and bases can be:

Strong – dissociate completely in solution
•HCl, NaOH

Weak – dissociate only partially in solution
•Lactic acid, carbonic acid

11. pH and pKapH and pKa
A molecule, or an atom group in a moleculeA molecule, or an atom group in a molecule, may , may lose or gainlose or gain a a
proton when the molecule is placed in an aqueous solution.
 
proton when the molecule is placed in an aqueous solution.
 
The exact probability that a molecule will be The exact probability that a molecule will be protonated or deprotonatedprotonated or deprotonated
depends on the depends on the pKa pKa of the molecule and theof the molecule and the pHpH of the solution of the solution

12. pH Review
pH = - log [H
+
]
H
+
is really a proton
Range is from 0 - 14
If [H
+
] is high, the solution is acidic; pH < 7
If [H
+
] is low, the solution is basic or alkaline ;
pH > 7

15. pHpH

The unit of the measurement useThe unit of the measurement use to to discribe discribe
the the alkalinityalkalinity or or acidityacidity of a substance is the of a substance is the
pHpH

pH stands for the potential of hydrogenpH stands for the potential of hydrogen

Measured on a scale 0-14Measured on a scale 0-14

Scale represents hydrogen ion concentrationScale represents hydrogen ion concentration

16. 
The pH is calculated The pH is calculated
by taking the negative by taking the negative
logarithm of the logarithm of the
hydrogen ion hydrogen ion
concentration, as concentration, as
shown below.shown below.

pH = -log10[H+]:pH = -log10[H+]:
where [H+] is the where [H+] is the
hydrogen ion hydrogen ion
concentrationconcentration
Acid-Base Balance

17. ACID/BASE BALANCE AND THE ACID/BASE BALANCE AND THE
BLOODBLOOD
Acidic Alkaline (Basic)
[OH
-
]
[H
+
]
Neutral
pH
0 14
7
Acidosis Alkalosis
Normal
7.35-7.45
Venous Blood
Arterial Blood
6.8
8.0
7.4

18. Normal acid-base balanceNormal acid-base balance
Arterial blood pH normally 7.4
Acidosis – pH below 7.35
Alkalosis – pH above 7.45
ie 0.05 pH units above or
below normal

19. The Body and pH
Homeostasis of pH is tightly controlled
Extracellular fluid = 7.4
Blood = 7.35 – 7.45
< 6.8 or > 8.0 death occurs
Acidosis (acidemia) below 7.35
Alkalosis (alkalemia) above 7.45

21. Small changes in pH can produce
major disturbances
Most enzymes function only with narrow pH
ranges
Acid-base balance can also affect electrolytes
(Na
+
, K
+
, Cl
-
)
Can also affect hormones

22. Persamaan Henderson-HasselbachPersamaan Henderson-Hasselbach
HHA A H H
++
+ + AA
--

CO2 + H2O CO2 + H2O H2CO3 H2CO3 H H
++
+ + HCO3HCO3
--

pH = pKpH = pK
aa + log [A + log [A
--
]/ [HA]]/ [HA]

pH = pKpH = pK
aa + log + log [[HCO3HCO3
--
]/[]/[H2CO3H2CO3] :] :

pKpK
aa H H
22COCO
33 = 6,1 = 6,1
pH plasma darah = pH plasma darah = 6,1 + log6,1 + log
= 6,1 + log 20/1 = 7,4= 6,1 + log 20/1 = 7,4
pH plasma darah = 7,4 pH plasma darah = 7,4
25 mmol/l : 20
1.25 mmol/l 1

23. RegulationRegulation
The process of acid-base regulation involves:The process of acid-base regulation involves:
1. 1. Chemical bufferingChemical buffering by intracellular and extracellular by intracellular and extracellular
buffersbuffers
2. Control of2. Control of pCO2 pCO2 by normal by normal respiratory functionrespiratory function  

3. Control of 3. Control of HCO3- HCO3- concentration and acid excretion by concentration and acid excretion by
the kidneythe kidney  

24. Acids, Bases and BuffersAcids, Bases and Buffers

AcidsAcids: An acid is defined as any compound, : An acid is defined as any compound,
which forms hydrogen ions in solution. For this which forms hydrogen ions in solution. For this
reason acids are sometimes referred to as reason acids are sometimes referred to as
"proton donors". To aid understanding of these "proton donors". To aid understanding of these
concepts consider an imaginary acid with the concepts consider an imaginary acid with the
chemical formula HA. In the first example in chemical formula HA. In the first example in
Figure 2, the acid dissociates (separates) into Figure 2, the acid dissociates (separates) into
hydrogen ions and the conjugate base when in hydrogen ions and the conjugate base when in
solution.solution.

BasesBases: A base is a compound that combines : A base is a compound that combines
with hydrogen ions in solution. Therefore, bases with hydrogen ions in solution. Therefore, bases
can be referred to as "proton acceptors".can be referred to as "proton acceptors".

Strong AcidsStrong Acids: A strong acid is a compound that : A strong acid is a compound that
ionizes completely in solution to form hydrogen ionizes completely in solution to form hydrogen
ions and a base. Example 2 illustrates a strong ions and a base. Example 2 illustrates a strong
acid in solution, where this dissociation is acid in solution, where this dissociation is
complete, such as HCl and NaOH.complete, such as HCl and NaOH.

Weak Acids and BasesWeak Acids and Bases: these are compounds : these are compounds
that are only partially ionised in solution. that are only partially ionised in solution.
Example 3 shows a weak acid in solution with Example 3 shows a weak acid in solution with
incomplete dissociation, such as :incomplete dissociation, such as :

CH3COOH <=> H+ + CH3COO-.
 
CH3COOH <=> H+ + CH3COO-.
 

25. Buffers

26. BuffersBuffers

Buffer solutions have the property of showing Buffer solutions have the property of showing only small changes of only small changes of pHpH when when
an an acidacid or or basebase is added, within limits.
  A buffer solution is prepared by mixing
is added, within limits.
  A buffer solution is prepared by mixing
a weak a weak acidacid with its conjugate with its conjugate basebase, i.e. the salt of the , i.e. the salt of the acid acid (e.g. CH3COOH (e.g. CH3COOH
and Na+CH3COO-).
  A buffer solution can also be prepared by mixing a weak
and Na+CH3COO-).
  A buffer solution can also be prepared by mixing a weak
basebase with its conjugate with its conjugate acidacid..

If we add If we add NaOH to an acetic NaOH to an acetic acidacid/sodium acetate/sodium acetate buffer solution the following buffer solution the following
reactions occur: NaOH => Na+ + reactions occur: NaOH => Na+ + OH-OH- completely, then completely, then
CH3COOH
  releases a proton (CH3COOH <=>
CH3COOH
  releases a proton (CH3COOH <=>
HH+ + CH3COO-)+ + CH3COO-)
to neutralize the OH- ions, to neutralize the OH- ions,
producing the reaction producing the reaction OH- + H+ <=>H2O,OH- + H+ <=>H2O,
and the and the change in change in pHpH will be minimal will be minimal.
 
.
 
Continuing to add NaOH will produce further dissociation of acetic Continuing to add NaOH will produce further dissociation of acetic acidacid until until
the concentration of acetic the concentration of acetic acidacid is significantly reduced.
 
is significantly reduced.
 
Then addition of more NaOH will have a greater impact on Then addition of more NaOH will have a greater impact on pHpH.
 
.
 
Adding HCl will have the opposite effect.
  H+ ions will bind to CH3COO-,
Adding HCl will have the opposite effect.
  H+ ions will bind to CH3COO-,
producing the weak producing the weak acidacid CH3COOH, minimizing the change in CH3COOH, minimizing the change in pHpH. .

27. Control of Acids

Buffer systems
Take up H+ or release H+ as conditions
change
Buffer pairs – weak acid and a base
Exchange a strong acid or base for a weak
one
Results in a much smaller pH change

28. Sistem yang berperan mempertahankan pH Sistem yang berperan mempertahankan pH
darah ( mekanisme kontrol) adalah darah ( mekanisme kontrol) adalah
BUFER (Dampar)BUFER (Dampar)
Bufer asam-basa adalah larutan dari senyawa kimia yang dapat Bufer asam-basa adalah larutan dari senyawa kimia yang dapat
mempertahankan perubahan pH yang minimal dalam suatu larutan mempertahankan perubahan pH yang minimal dalam suatu larutan
bila ditambah basa atau asambila ditambah basa atau asam
1. 1. Bufer kimiaBufer kimia (asam Karbonat, bikarbonat merupakan (asam Karbonat, bikarbonat merupakan
sistem bufer tubuh yang penting walaupun tidak seefisien bufer sistem bufer tubuh yang penting walaupun tidak seefisien bufer
fisiologi) & protein/fosfat plasma)fisiologi) & protein/fosfat plasma)
2. 2. Bufer fisiologiBufer fisiologi ( paru2 dan ginjal)( paru2 dan ginjal)
3. 3. Bufer biologiBufer biologi (darah)(darah)

29. 1.BUFER KIMIA1.BUFER KIMIA
CO2 + H2O CO2 + H2O H2CO3 H2CO3 HH
++
+ HCO3 + HCO3
--

Cairan ekstraseluler normal ratio Cairan ekstraseluler normal ratio
[HCO3[HCO3
--
]/[H]/[H
22COCO
33] : 20/1] : 20/1
Ratio ini menentukan keseimbangan asam-basa pada keadaan Ratio ini menentukan keseimbangan asam-basa pada keadaan
pH : bila pH pH : bila pH lebih dari 7.4lebih dari 7.4  ALKALOSISALKALOSIS
kurang dari 7.4kurang dari 7.4  ASIDOSISASIDOSIS

30. 1.a Bicarbonate buffer
Sodium Bicarbonate (NaHCO
3) and carbonic
acid (H
2CO
3)
Maintain a 20:1 ratio : HCO
3
-
: H
2CO
3
HCl + NaHCO
3 ↔ H
2CO
3 + NaCl
NaOH + H
2CO
3 ↔ NaHCO
3 + H
2O

31. 1.b Phosphate buffer
Major intracellular buffer
H
+
+ HPO
4
2-
↔ H
2PO4
-
OH
-
+ H
2PO
4
-
↔ H
2O + H
2PO
4
2-

32. 2.BUFER FISIOLOGIS2.BUFER FISIOLOGIS

Bila bufer kimia tidak dapat menstabilkan pH =7.4 maka Bila bufer kimia tidak dapat menstabilkan pH =7.4 maka
dilanjutkan bufer fisiologis sebagai berikut:dilanjutkan bufer fisiologis sebagai berikut:
a) PARU2a) PARU2

Apabila pH turun (Apabila pH turun (CO2 meningkatCO2 meningkat):):

Paru2 berusaha meningkatkan pernafasan Paru2 berusaha meningkatkan pernafasan
((hiperventilasihiperventilasi))
•
Apabila pH naik (Apabila pH naik (CO2 menurunCO2 menurun):):
- Paru2 berusaha menurunkan pernafasan - Paru2 berusaha menurunkan pernafasan
((hipoventilasihipoventilasi))

33. Peranan sistem pernapasan dalam Peranan sistem pernapasan dalam
mempertahankan PH darahmempertahankan PH darah
Pengeluaran COPengeluaran CO
22 dari darah dan pasokan O dari darah dan pasokan O
22
pada jaringan adalah fungsi utama sistem pada jaringan adalah fungsi utama sistem
pernapasan pernapasan

Sistem pernapasan dikendalikan oleh pusat Sistem pernapasan dikendalikan oleh pusat
pernapasan di otakpernapasan di otak

Mekanisme pernapasan dapat dirangsang Mekanisme pernapasan dapat dirangsang
oleh oleh turunnya pH, turunnya pOturunnya pH, turunnya pO
22, ,
peningkatan suhupeningkatan suhu dll. dll.

34. Respiratory center
Spinal cord
Phrenic nerve (and intercostal
nerves).
Resp. muscles
pH
pO2
Suhu

35. 2. Respiratory mechanisms
Exhalation of carbon dioxide
Powerful, but only works with volatile acids
Doesn’t affect fixed acids like lactic acid
CO
2 + H
20 ↔ H
2CO
3 ↔ H
+
+ HCO
3
-
Body pH can be adjusted by changing rate
and depth of breathing

36. As PaCO2 levels continue increasing,
CO2 accumulates in the body tissues and fluids, including cerebrospinal
fluid and the respiratory center in the medulla.
 
Like in the blood, the CO2 combines with H2O to form H2CO3,
which in turn dissociates into H+ and HCO3- ions.
 
This increase in CO2 and H+ ions stimulates the respiratory center to
increase the respiratory rate (correction) to excrete the excess CO2 and
bring the pH back into normal range.
  If correction is successful

increased respiratory rates, perhaps shallow respirations, a decreasing PaCO2 and an increasing pH.
pH
HIPERVENTILASI
PaCO2
HCO3-
H2CO3

37. b) Renal (Ginjal) b) Renal (Ginjal)
(mekanisme renal (mekanisme renal lebih lambatlebih lambat dibanding paru2) dibanding paru2)

Apabila pH turun (CO2 meningkat):Apabila pH turun (CO2 meningkat):

Ekskresi Ekskresi H H
++
(NH (NH
44) ke urine meningkat) ke urine meningkat

Reabsorpsi Na Reabsorpsi Na
++
(sodium) dan HCO3- dari ginjal ke (sodium) dan HCO3- dari ginjal ke
darah meningkat ( 1 Nadarah meningkat ( 1 Na
++
untuk 1 H untuk 1 H
++
) ) mengatur mengatur
pertukaran pertukaran NaNa
+ +
dan H dan H
++

38. 3. Kidney excretion
Can eliminate large amounts of acid
Can also excrete base
Can conserve and produce bicarb ions
Most effective regulator of pH
If kidneys fail, pH balance fails

39. As respiratory mechanisms (correction) fail,
the increasing PaCO2 stimulates the kidneys to retain
both HCO3- and sodium (NA+) ions and
to excrete H+ (compensation) ions.
 
The H+ is excreted as free H+ and some as ammonium (NH4).
 
Meanwhile, the NA+ and HCO3- ions combine to form sodium
bicarbonate (NaHCO3),

Look for a more acidic urine, increasing pH and bicarbonate values, slower (and perhaps
shallow) respirations.
 
*pertukaran Na+-H+ *pertukaran Na+-H+
*pembentukan ammonia*pembentukan ammonia
*reabsorpsi HCO3-*reabsorpsi HCO3-

40. Kidney Regulation of
Acid-Base Balance

41. Rates of correction
Buffers function almost instantaneously
Respiratory mechanisms take several minutes
to hours
Renal mechanisms may take several hours to
days

42. Konsentrasi HKonsentrasi H
++
menggambarkan sebagai pH darah menggambarkan sebagai pH darah
pH = - log (HpH = - log (H
++
) )
Larutan dinamakan ASAM atau BASA tergantung Larutan dinamakan ASAM atau BASA tergantung
dari besar pHdari besar pH
pH darah berkisar : 7.35 – 7.45 pH darah berkisar : 7.35 – 7.45

45. 3. 3. Bufer BiologisBufer Biologis

Bufer terakhir adalah bufer biologis yaitu Bufer terakhir adalah bufer biologis yaitu HEMOGLOBINHEMOGLOBIN
Hb+ + Hb+ + H+H+ HH-Hb -Hb

Hb Hb  berperan penting untuk bufer H berperan penting untuk bufer H
++
yang dilepas oleh yang dilepas oleh
karbonik anhidrase pada eritrositkarbonik anhidrase pada eritrosit

46. Protein Buffers
Includes hemoglobin, work in blood and ISF
Carboxyl group gives up H
+

Amino Group accepts H
+
Side chains that can buffer H
+
are present on 27
amino acids.

47. CO2 + H2O CO2 + H2O H2CO3 H2CO3 H H
++
+ HCO3 + HCO3
--

Excretion regulated by the kidneys:
Metabolic control
Excretion regulated by the lungs:
Respiratory control
Carbonic anhydrase

48. 
Komponen gas darah arteri dlm keadaan Komponen gas darah arteri dlm keadaan
NORMAL :NORMAL :

pHpH 7.35-7.457.35-7.45

PaCO2PaCO2 35-45 mmHg35-45 mmHg

HCO3-HCO3- 18-24 mEq/L 18-24 mEq/L

PaO2PaO2 50-80 mmHg 50-80 mmHg

49. Enzim karbonik anhidraseEnzim karbonik anhidrase

Enzim ini mengandung ZincEnzim ini mengandung Zinc
Mengkatalisis reaksi Mengkatalisis reaksi
CO2 + H2O CO2 + H2O H2CO3 H2CO3 H H
++
+ HCO3 + HCO3
--

Terdapat pada eritrosit dan pada sel Terdapat pada eritrosit dan pada sel
tubulus ginjal tubulus ginjal  sumber HCO3 sumber HCO3
--

Melalui reaksi ini ginjal mengatur kadar Melalui reaksi ini ginjal mengatur kadar
HCO3HCO3
--
plasma dengan cara reabsorpsi dan plasma dengan cara reabsorpsi dan
sintesis HCO3sintesis HCO3
--
, sedangkan eritrosit , sedangkan eritrosit
mengatur melalui responsnya terhadap mengatur melalui responsnya terhadap
perubahan pCO2perubahan pCO2

50. 
Selamat belajar.Selamat belajar.

51. Hydrogen Ion Buffering

52. Acidosis and Alkalosis