2011 Kidney Meuti 12 Acid Base Part 1

Front 1

Acid

Back 1

Substance that can donate a Proton
Hydrogen ion (H+)
Bronsted-Lowry definition

Front 2

Volatile Acid

Back 2

Acids that can be excreted from the body in a gaseous form

Front 3

Non-Volatile Acid

Back 3

Metabolic acids that cannot be converted to a gas- must be excreted through the kidneys
i.e. Lactic acid and ketones

Front 4

2 non-volatile Acids

Back 4

i.e. Lactic acid and ketones

Front 5

Strong Acid

Back 5

A Substance that readily and almost irreversible donates a H+ ion
Increases H+ concentration

Front 6

Weak Acid

Back 6

A Substance that reversibly donates a H+
Has less effect on H+ concentration

Front 7

Acidic Solution
ph

Back 7

pH < 7.0

Front 8

Base

Back 8

Substance that can accept a proton
H+ Ions

Front 9

Strong Base

Back 9

A Substance that binds H+ and does not readily dissociate back
Decreases H+ concentration

Front 10

Weak Base

Back 10

A Substance that reversibly binds to H+
Small effect on H+ concentration

Front 11

Basic Solution
ph

Back 11

pH > 7.0

Front 12

pH
Defined as

Back 12

the Negative Logarithm (base of 10) of H+

Front 13

pH
Represents

Back 13

H+ concentration in a solution

Front 14

Normal arterial H+ concentration is

Therefore normal arterial pH =

Back 14

40 nEq/L

-log(40x10-9)=7.40

Front 15

Henderson-Hasselbalch equation
Describes

Back 15

Acid-base equilibrium

Front 16

Describes Acid-base equilibrium
pH=

Back 16

6.1 + log([HCO3-] / 0.03*PaCO2)

Front 17

the pKa of carbonic acid

Back 17

6.1

Front 18

is the solubility coefficient of CO2 in the blood

Back 18

0.03

Front 19

Buffer

Back 19

Any substance that when added to a solution is able to neutralize both acids and bases without changing the original pH of the solution

Front 20

Buffer
Helps resist changes in pH by

Back 20

readily accepting or giving up H+ ions

Front 21

to maintain pH of 7.4
The body

Back 21

contains buffers

Front 22

OSIS”
The suffix for a

Back 22

a pathological process that alters arterial pH

Front 23

Acidosis’ :

Back 23

↓pH or ↑H+

Front 24

Alkalosis’:

Back 24

’: ↑pH or ↓base

Front 25

The body is not tolerant of wide changes in pH and is constantly working to maintain pH

Back 25

pH at 7.35-7.45

Front 26

The body has 3 ways to maintain acid-base balance

Back 26

Immediate Chemical buffering
Respiratory compensation
Renal compensation

Front 27

1st: buffer system

Back 27

Extracellular & Intracellular fluid buffer system
Occurs within seconds

Front 28

2nd buffer system

Back 28

Respiratory compensatory mechanism
Balances within minutes

Front 29

3rd: buffer system

Back 29

renal compensatory mechanism
slowly readjusts the pH
Functions for hours or days until pH is almost normal

Front 30

the most important buffer in the ECF compartment

Back 30

Bicarbonate-

Front 31

Extracellular Fluid Buffer System

Back 31

Bicarbonate-

Front 32

important buffer in the blood

Back 32

Hemoglobin-

Front 33

Extracellular Fluid Buffer System
Exchange

Back 33

of H+ for Na+ and CA2+ from bone and by the exchange of H+ for intracellular K+

Front 34

Intracellular Fluid Buffer System
Three other proteins act as important buffers

Back 34

Albumin
Phosphate
Ammonium

Front 35

Most important buffer in the body

Back 35

Bicarbonate Buffer

Front 36

Bicarbonate Buffer
ph

Back 36

6.1

Front 37

Bicarbonate Buffer
The major components can be independently regulated by

Back 37

the lungs and the kidneys

Front 38

Compensatory Mechanisms -ECF buffer system

Reversible reaction that occurs depending on the body’s needs
Consists of (formula)

Back 38

H2O + CO2 ↔ H2CO3 ↔ H+ + HCO3-

Front 39

Bicarbonate Buffer
Water combines with Carbon dioxide to form

Back 39

to form carbonic acid with can dissociate into hydrogen ions plus bicarbonate ion

Front 40

The reaction between water and carbon dioxide is catalyzed by the enzyme,

Back 40

carbonic anhydrase

Front 41

Bicarbonate Buffer


This buffer is effective against metabolic but NOT

Back 41

respiratory acid/base disturbances

Front 42

The most important non carbonic buffer in ECF

Back 42

Hemoglobin

Rich in Histidine

Front 43

Hemoglobin
Rich in Histidine
Effective buffer from pH of

Back 43

5.7 to 7.7

Front 44

Hemoglobin
Is capable of buffering both

Back 44

buffering both volatile and nonvolatile acids

Front 45

Pulmonary Compensation

Back 45

Increase or decrease in alveolar ventilation

Front 46

Pulmonary Compensation
Mediated by

Back 46

chemoreceptors within the brain stem
Respond to changes in CSF fluid pH

Front 47

Minute Ventilation increases

every 1mmHg increase in PaCO2

Back 47

increases 1-4 L/min

Front 48

Pulmonary Compensation
Hyperventilation excretes

Back 48

CO2
‘Blows off’ acid

Front 49

Hypoventilation results in retention of

Back 49

CO2

Front 50

Hypoventilation results

Back 50

Increase the amount of acid available to combine with excess bicarbonate to form carbonic acid
PaCO2 usually does not rise above 55mmHg in response to metabolic alkalosis

Front 51

Compensatory Mechanisms

3 Renal Mechanisms

Back 51

Able to control the amount of bicarbonate reabsorbed from tubular fluid
Able to form new bicarbonate
Able to eliminate H+ in the form of titratable acids and ammonium ions

Front 52

Large numbers of bicarbonate ions are filtered continually into the

Back 52

glomerular filtrate, which removes base from the blood

Front 53

Large numbers of hydrogen ions are secreted at the same time into the tubular lumens by the tubular epithelium thus

Back 53

removing acid

Front 54

If more H+ are secreted than bicarbonate ions are filtered, there will be a

Back 54

net loss of acid from extracellular fluid

Front 55

If more bicarbonate is filtered than hydrogen secreted, there will be a

Back 55

net loss of base

Front 56

Secretion of H+ ions and reabsorption of bicarbonate by

Back 56

the renal tubule

Front 57

Combination of excess H+ ions with buffers in the tubule
causes

Back 57

Able to produce excess bicarbonate

Front 58

Secretion of H+ and reabsorption of HCO3-
Occurs in

Back 58

Occurs in all parts of tubule

Front 59

where Reabsorption of bicarbonate

Back 59

Proximal: 85% Bicarbonate reabsorption
Thick limb of ascending loop of henle: 10% reabsorption
Rest is reabsorbed in the distal tubule and collecting ducts

Front 60

H+ ion secretion
Secreted by

where? 3x

with

Back 60

secondary active transport

proximal tubule, thick ascending LOH, and in the distal tubule

With use of a Na-H counter- transport

Front 61

85% Bicarbonate reabsorption
occurs where

Back 61

Proximal:

Front 62

Bicarb in the lumen reacts with

Back 62

with H+ ion (which is transported into the lumen for exchange of Na reabsorption).

Front 63

Bicarb in the lumen reacts with H+ ion to form

Back 63

This forms carbonic acid which dissociates into water and carbon dioxide.

Front 64

H+ secretion Occurs in specialized cells called

Back 64

intercalated cells