pH & CO2 quiz prep Flashcards
(148 cards)
1
Q
What catalyst speeds of the reaction of the hydrolysis equation?
A
Carbonic Anyhydrase
2
Q
What is the Hydrolysis equation?
A
CO2 + H2O = H2CO3 = H+ + HCO3-
3
Q
What is the pH range compatible with life?
A
6.80 - 7.80
4
Q
What is the normal pH scale?
A
0-14
5
Q
When you increase H+ what effect does it have on pH? Increase or decrease?
A
Increase
6
Q
What is the ratio of Bicarb to pH balance?
A
1:20
7
Q
How much acid does body produce each day during normal function?
A
13,050 mEq/l of acid is produced each day
8
Q
Name the 2 ways that the body deals with the acid it produces?
A
Acid excretion via lungs or kidneys
Acid Buffering
9
Q
How much acid does the lungs excrete each day?
A
13,000 mEq/L
10
Q
What is H+Cl?
A
Hydrochloric Acid–this is a strong acid
11
Q
What is H2CO3?
A
Carbonic Acid–this is a weak acid
12
Q
What is the formula to compute pH?
A
pH= - log [H+]
13
Q
Name the two ways O2 is carried in the blood?
A
Dissolved (PaO2- partial pressure of O2 dissolved in arterial blood)
Combined (SaO2) = oxygen saturation of arterial Hb & combined O2
14
Q
Which value for oxygenation is directly measured so is more reliable? PaO2 or SaO2
A
PaO2
15
Q
This acid is a by-product of the Kreb’s cycle?
A
Lactic Acid
16
Q
What is the definition of pH?
A
Measurement of the acidity or alkalinity of a substance
17
Q
This law deals with solubility of a substance. It states that CO2 is much more soluble than O2- Per this law the amount of gas dissolving in liquid is directly proportional to gas partial pressure; Co2 is 24 x more soluble than CO2; What is this principle? A. Graham's Law B. Henderson-Hasselbach C. Henry's Law D. Haldane Effect
A
C. Henry’s Law
18
Q
This law deals with diffusion of a gas through a liquid which is directly proportional to its solubility coefficient & inversely proportional to sq root of its density; Because O2 is a lighter molecule it diffuses through a gas medium 1.17 times faster than CO2; What is this principle? A. Graham's Law B. Henderson-Hasselbach C. Henry's Law D. Haldane Effect
A
A. Graham’s Law
19
Q
Hydrogen in chemical combination with other elements is/is not part of the pH measurement?
A
Is Not; Only hydrogen in free ionic form is part of the measurement of free hydrogen ion concentration; therefore, hydrogen in chemical combination with other elements is not part of the free [H+]
20
Q
What is the pH measurement?
A
pH is a method of assessing the amount of H+ present in a given fluid
-log [H+]
21
Q
The relationship between pH and [H+] is?
A. Direct
B. Linear
C. Inverse
A
C. Inverse
The relationship is inverse & logarithmic
22
Q
A large increase in [H+] reflects a ______ change in pH. Doubling the normal [H+] results in _____ change to pH.
A
A large increase in [H+] reflects only slight change in pH; 0.3 change in pH
23
Q
pH measures activity or concentration of [H+]?
A
Activity; It is the balance of acids & bases at any given moment
24
Q
Most [H+] are not really free but are combined with ______ to form ______ ions
A
Most [H+] are not really free but are combined with H2O to form hydronium ions.
25
CNS depression is a clinical manifestation of academic pH; Name 4 signs of this condition.
```
Drowsiness
Lethargy
Disorientation
Coma
Death
```
26
CNS excitability is a clinical manifestation of alkalotic pH; Name the 5 signs of this condition.
```
Excitability
Irritability
Arrhythmias
Spasms/Tetany
Convulsions
Deatb
```
27
What is the ratio of Bicarb to Carbonic Acid
1 carbonic acid H2CO3 : 20 Bicarbs HCO3-
28
What are the two ways that the body deals with acids?
Excretion
| Buffering
29
Carbonic Acid is removed in the lungs in the form of what?
CO2
30
What is a volatile acid? Give an example
An acid that can be converted from a liquid to a gas; Carbonic acid is an example of a volatile gas
31
Doubling the normal [H+] results in a (0.03/0.3) increase or decrease in pH?
Doubling the normal [H+] results in a 0.3 decrease in pH.
32
Any chemical substance capable of combing with or accepting a hydrogen ion in solution is called a ?
Base
33
Any chemical substance capable of donating a hydrogen ion is a ?
Acid
34
What are the 2 major organs of acid excretion?
Lungs & kidneys
35
The lungs excrete (volatile/fixed) acids?
The lungs excrete volatile acids
36
The major blood base of clinical significance is?
HCO3-
37
The organs responsible for the regulation of blood bases is the lungs/kidneys?
kidneys
38
Name a weak acid & a strong acid:
Weak: CO2
Strong: Hydrochloric acid HCl
39
A substance that can act either as an acid or base is referred to as? What is an example?
amphoteric; Hb can act as either an acid or base in the blood
40
Which organ removes fixed acids?
kidneys
41
What is a fixed acid?
Those that cannot be converted to a gas; this is a normal part of metabolism
42
What is catabolism?
A part of metabolism that involves the breakdown of substances into smaller units & release of energy
43
What is anabolism?
A type of function of metabolism in which involves creation of a larger molecule from a smaller substance. This reaction requires energy
44
Catabolism of proteins produces what 2 acids?
Phosphoric acids & sulfuric acids
45
Some diseases will produce too much _____ and the kidneys cannot handle them?
Fixed acids; they will build up in the body
46
Renal failure by the mechanism of protein metabolism produces too much?
Phosphoric & sulfuric acids
47
Diabetes by the mechanism of ______ metabolism produces to much _________?
Diabetes by the mechanism of incomplete lipid metabolism (fat) produces to much ketoacids (aka acetoacidic or beta-hydroxybutaric acid
48
Anoxia by the mechanism of _______ metabolism produces too much ________ acid.
Anoxia by mechanism of carbohydrate metabolism produces too much lactic acid
49
_______ soak up acids or neutralize bases minimizing changes in pH.
Buffers
50
Every acid must have a related _____ that is present on dissociation of the hydrogen ion.
Base
51
An acid in conjunction with its associated base is sometimes referred to as a ______.
Conjugate base
52
The conjugate base of H2CO3 is ________, and the conjugate base of HHb is _________.
weak acid; salt of the conjugate base of weak acid
53
What is the conjugate base of this pair: HCl = H+ + Cl-
Cl-
54
Strong acids have a high/low degree of disassociation (many free H+ ions)
Strong acids have a high degree of disassociation
55
Water is a strong/weak acid
weak acid
56
A buffer system converts strong acids to _______ or strong bases to _________ .
A buffer system converts strong acids to weak acids or strong bases to weak bases
57
What releases the most H+ (strong acids or weak acids)?
Strong acids
58
What are the two types of buffer systems the body uses?
Bicarb system
| Non-Bicarbonate system
59
A bicarbonate buffer system is made up of __________ acid & ____________
A bicarbonate buffer system is made up of a weak acid & the salt of its conjugate base.
60
List a Bicarbonate buffer:
H2CO3/NaHCO3-
61
In a buffer pair if a strong acid is added what happens to the buffer pair, how is it changed?
It is changed to a weak acid & a salt
| HCL + H2CO3/NaHCO3- = NaCL + H2CO3
62
In general, the stronger the acid the stronger/weaker is its conjugate base.
Weaker
63
Deoxygenated/oxygenated hemoglobin most readily picks up hydrogen ions.
deoxygenated
64
If a strong base sodium hydroxide NaOH- is added to the system, the buffer system will change to a strong/weak base & _________
It will change to a weak base & water
| NaOH- + H2CO3/NaHCO3 = NaHCO3 + H2O
65
Metabolic compensation is also known as ?
Buffering
66
Which type of acid breaks apart easiest, a strong/weak acid?
A strong acid breaks apart easieast
67
Bicarbonate buffering represents how much of the bodies buffering system? what percentage?
53%
68
Name 4 other ways the body can buffer? The non-bicarb systems which account for the other 47% of buffering that takes place in the body
Hb
Organic Phosphates
Inorganic Phosphates
Plasma proteins
69
The body buffers in both the extra-cellular fluid & intra-cellular fluid; Name the buffering systems in both systems & the percentages.
Extra-cellular buffers:
Plasma Bicarbonate = 35%
Plamsa Protein = 7%
Inorganic Phosphates = 1%
```
Intra-cellular buffers:
Erythrocyte Bicarbonate = 18%
Hb = 35%
Oxyhemoglobin = 1%
Inorganic/organic phosphates 3%
```
70
The largest extra-cellular buffer is plasma ________ & the largest intra-cellular buffer is _____.
```
Extra-cellular = plasma bicarbonate
Intra-cellular = Hb
```
71
What is the most important intra-cellular fluid buffer?
Hemoglobin
72
The effectiveness of buffering depends on 3 qualities?
1. pK
2. Quantity
3. Open vs. Closed System
73
What is pk?
Point at 50% dissociation
74
What is the pk of carbonic acid in the blood?
6.1
75
Strong acids are buffered by the dissociated portion of the buffer pair which is?
NaHCO3
76
Strong bases are buffered by the undissociated portion which is?
H2CO3
77
Which is better for buffering an open or closed system & why?
An open system is most effective. In a closed system the buffer becomes less effective as the products of buffering accumulate which is what happens for most blood buffers. Bicarbonate functions in an open system as CO2 does not accumulate. Hb is a closed system
78
What describes the fixed inter-relationship between PCO2, pH, & HCO3-;
Henderson-Hasselbach Equation
79
Which do we buffer better, acids or bases & why?
We buffer acids better as it is closest to the pk of 6.1
80
What is KA mean
Equilibration Constant= this means the equilibration both ways is constant
81
This principle is known as?
| The product of the concentrations on the right equals the product of the concentrations on the left
The law of mass action
82
Because the concentration of H+ in the blood is very small Henderson resolved this by how?
taking the negative log of both sides of an equation
83
What is the formula for KA
KA = [H+] [HCO3-] / H2CO3
84
What is the formula for pK?
pK = - log KA
85
What does pK represent or why is it important?
pk represents the pH at which maximum buffering can be achieved; the pk of bicarbonate & carbonic acid is 6.1
86
Since the amount of carbonic acid is very small we measure what?
CO2
87
How is carbonic acid & CO2 related? Directly/indirectly or linearly/logarithmically
direct/linearly related
88
In the Henderson Hasselbach equation, carbonic acid concentration is replaced by what?
partial pressure of CO2 (which is 40) x the solubility coeffficent (0.03)= 1.2
89
What is the value of bicarb in the Henderson hasselbach equation which is the amt in arterial plasma?
24 mEq/L
90
Write the formula for the Henderson Hasselbach equation:
pH = pk + log HCO3/H2CO3
91
If HCO3- drops by half & PaCO2 remains the same then ph will?
Decrease
92
```
A pH of 7.40 means?
a. HCO3- is normal
b. PaCO2 is normal
C. The ratio of HCO3- to PaCO2 is normal
D. All of the above
```
C. The ratio of HCO3- to PaCO2 is normal
93
What is the relationship between CO2 and pH?
| Direct/inverse
Inverse
94
Where is CO2 measured? intracellular plasma or extracellular plasma
Extra-cellular plasma
95
T or F: CO2 is a gas that can move across the cell membrane
True
96
What is the equation that regulates CO2?
hydrolysis equation
97
T or F: CO2 will be the same in the ICF & ECF
True
98
A CO2 greater than 45 is referred to as?
Hypoventilation, hypercarbia, hypercapnia
99
Name 3 terms used to describe CO2 less than 35
Hyperventilation, Hypocarbia, Hypocapnia
100
What are some clinical manifestations of hypercarbia or hypoventilation, when PaCO2 is greater than 45 or acidic? 6 symptoms
```
Pinpoint pupils
Lethargy
Coma
Hallucinations
Headaches
Peripheral vasodilation
```
101
What are some clinical manifestations of hypocarbia or hyperventilation, when PaCO2 is less than 35 or alkalitic?
```
Dizziness
Tingling fingers/toes
Spasms
Tetany
Arrhythmia
```
102
T or F: Chemical Equilibiration means concentrations on each side are equal.
False; when concentrations are greater on one side than the other the reaction is said to be shifted; the rate of the reaction on one side is equal to the rate of reaction on the other side; in a closed system the reaction continues until it reaches dynamic equilibration
103
What is described here?
If one constituent is added to the system a new equilibration is reached; If add one reactant on right reaction will shift to the left
Law of mass action
104
What demonstrates the relationship between CO2 & H2CO3; Each mole of H2CO3 is in equilibration with 340 moles of CO2
Hydrolysis equation
105
Where is the hydrolysis equation faster, inside or outside the cell & why?
It is faster inside of the cell because of the presence of carbonic anhydrase
106
Where is carbonic anhydrase found?
Kidneys & Liver
107
What does PaCO2 equal?
combination of the quantity of entering the system & CO2 leaving the lungs
108
What is VCO2?
Volume of CO2 produced in a minute
109
What is VA?
Alveolar Ventilation which is the amount of fresh gas that reaches the alveoli each minute
110
What determines the amount of PaCO2?
The balance of VCO2 & VA at any moment
111
PaCO2 is directly/indirectly related to production; PaCO2 is directly/indirectly related to excretion
PaCO2 is directly related to production & indirectly related to excretion
112
List two factors that affect CO2 production?
Temperature & Metabolism
113
An increase in CO2 production is normally balanced by ________.
Increase in ventilation
114
Give examples of things that cause excessive CO2 production?
Sepsis
Burns
TPN (Total parenteral nutrition)
NaHCO3 administration
115
Give examples of conditions that cause the ventilation system to be impaired, causing too much CO2 buildup?
CNS depression, muscle paralysis
Chronic lung disease
Pharmacologic intervention
116
CO2 excretion is directly/inversely related to alveolar minute ventilation?
CO2 excretion is inversely related to alveolar minute ventilation
117
T or F: Minute ventilation is a reliable indicator of the adequacy of ventilation.
False: Minute ventilation cannot tell us if the lungs are excreting CO2 in proportion to production
118
What is the best indicator to assess the adequacy of ventilation in relationship to CO2 & how is it obtained?
PaCO2 is the best index to assess adequacy of ventilation & it is obtained via ABG
119
How is alveolar ventilation different from minute ventilation?
Only the gas that reaches functional (perfused) alveoli is considered alveolar ventilation; dead-space volume is subtracted from the tidal volume
120
What is the formula for alveolar ventilation?
VA (with period above V)
| VA = (Vt - VD) x RR
121
The amount of gas moving in and out of the lungs with each breath is?
Tidal volume
122
PaCO2 varies directly/inversely with alveolar ventilation?
Inversely
123
```
What is the only reliable index of the adequacy of ventilation?
A. O2
B. CO2
C. PaCO2
D. H2CO3
E. HCO3-
```
C. PaCO2
124
List 2 general mechanisms in which CO2 is transported in the blood?
Dissolved & Combined
125
State the amount & significance of CO2 that is dissolved & where it is dissolved.
10% is dissolved. 5% dissolved in the plasma; & 5% is dissolved in the RBC
126
What is the major mechanism of CO2 transport?
HCO3; accounts for 68%; 63% in RBC & 5% in plasma
127
Why is dissolved transport so important in CO2 transport even though it represents only 10%?
All combined CO2 must become dissolved to get in/out of the cell
128
Name the 4 basic forms that CO2 is transported:
dissolved CO2, carbonic acid, bicarbonate, carbamino compounds
129
What is the solubility coefficient of CO2 in mEq/L
.03 mEq/L
130
What phenomenon is responsible for the large amount of CO2 transported via bicarbonate?
Chloride Shift--the exchange of bicarbonate ions for chloride anions across the RBC; this is due to the electrical gradient created between intracellular fluid and plasma; results in movement of chloride anions into RBC from plasma
131
Another form of CO2 transport which is small amount occurs when CO2 can combine with hemoglobin which contains the protein globin; the combined form of Hb and CO2 is called and accounts for what percent of the combined transport of CO2?
Carbamino & 21%
132
What are 3 causes of respiratory failure?
Failure to ventilate
Failure to oxygenate
Failure to protect airway
133
The amount of CO2 entering the blood depends primarily on the ______?
Metabolic Rate
134
The volume of CO2 produced per minute is designated as the?
VCO2
135
______ is the amount of fresh gas that reaches functional alveoli?
Alveolar ventilation
136
An increase in blood PaCO2 can increase after IV administration of what drug?
Sodium Bicarbonate
137
An increase in alveolar ventilation results in an increase/decrease of PaCO2?
Decrease
138
What is the formula for minute ventilation?
Vt x RR
139
The change in equilibrium in response to a change in the amount of one of the reaction constituents is called?
Law of Mass Action
140
There is an increase/decrease/no change in the amount of carbonic acid present in the blood as it passes the tissues
Increase
141
The solubility coefficient of CO2 is higher/lower than the solubility coefficient of O2. Which laws states this?
CO2 is 24 x more soluble than O2; so it is higher; per henry's law
142
The hydrolysis reaction occurs faster in the plasma or RBC?
RBC
143
```
Hydrogen ions generated by Hydrolysis reaction within the RBC are buffered by?
a. Hb
b. Bicarbonate
C. Carbonic Acid
D. they are not buffered
```
A. Hb
144
Bicarbonate ions are transported through the cell membrane in exchange for :
a. Cl-
b. PO4-
c. K+
A. Cl-
145
The affinity of hemoglobin for CO2 is greater/less when it is combined with O2?
Less
146
The regulation of _______ Is the single most important role of the kidneys in acid base balance.
Bicarbonates
147
Name 2 substances that must be present in a buffer solution?
Weak acid
| Salt of the conjugate base of weak acid
148
```
A strong acid in a buffer solution will react with?
A. Salt
B. Weak Acid
C. Base
D. H2O
```
A. Salt
