Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

year 2 > renal physiology part 2 - acid base balance > Flashcards

renal physiology part 2 - acid base balance Flashcards

1
Q

what is the pH of arterial blood

A

7.45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the pH of venous blood

A

7.35

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the average pH of blood

A

7.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why is venous blood more acidic than arterial blood

A

due to presence of CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is considered acidotic

A

below 7.35

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is considered alkalotic

A

above 7.45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the equation for pH using log and [H+]

A

log(1/[H+])

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

an increase in [H+] does what to the pH

A

lowers the pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

small change in pH reflect ____ changes in [H+]

A

large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

acidosis can lead to ____ of the CNS

A

depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

alkalosis can lead to ____ of the peripheral and later the central nervous system

A

overexcitability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are some examples of changes in the nervous system due to alkalosis

A 
pins and needles (sensory)
muscle spasms (motor) - fatal if respiratory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

change of pH of bodily fluids will alter the ______ of proteins causing a knock on effect on ____

A

secondary structure

enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

increased plasma [H+] ______ K+ secretion in renal tubules

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 3 ways in which H+ is added to the bodily fluids

A

carbonic acid formation
inorganic acids produced during breakdown of nutrients
organic acids resulting from metabolism e.g. lactic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a strong acid

A

dissociates completely in solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is a weak acid

A

partially dissociates in solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the first line defence to any change in pH

A

buffer systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does a buffer system consist of

A

one substance can yield a H+ ion if [H+] decreases

one substance can bind to H+ if [H+] increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the equation of a buffer solution

A

HA H+ + A-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the base in the buffer solution

A

A-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the undissociated acid in the buffer solution

A

HA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the proton in the buffer solution

A

H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

if H+ is added to a buffer system equilibrium shifts to the ….
why?

A

left
H+ is mopped up by A- leading to formation of more HA
[HA] rises, [A-] falls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

if base B- is added to a buffer system, equilibrium shifts to the….
why?

A

right
base is tied up by combining with H+ allowing more HA to dissociate
[HA] falls, [A-] rises

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

at equilibrium what is the equation for K (dissociation constant) of a weak acid

A

[H+]{A-}/[HA]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the henderson hasselbach equation

A

pH = pK + log[A-]/[HA]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the most important physiological buffer system in the body

A

CO2 - HCO3 buffer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what enzyme converts CO2 + H20 –> H2CO3 (carbonic acid)

A

carbonic anhydrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what does carbonic acid dissociate to

A

H+ + HCO3-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the pK for carbonic acid

A

6.1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is normal arterial PCO2

A

40mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is normal [HCO3-]

A

24mmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what controls [HCO3-]

A

kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what controls PCO2

A

lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

how can the kidneys control HCO3- (2 ways)

what do both these processes depend on

A

variable reabsorption of filtered HCO3
and kidneys can add new HCO3 to the blood
- both depend on H+ secretion into the tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

true/false

the concentration of bicarbonate can be higher in the renal vein than in the renal artery

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

where is bicarbonate reabsorbed

A

PCT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is needed in order to reabsorb bicarbonate ions

A

hydrogen ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

how is bicarbonate reabsorption started

A

H2O and CO2 in the epithelial cell of the PCT form carbonic acid which then dissociates into HCO3- and H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

how does the bicarbonate get from the epithelial cell into the interstitial fluid

A

Na+/HCO3- co transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

where does the H+ ion (the other dissociate) go and how

A

goes into the filtrate via the Na+/H+ antiporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what happens to this H+ ion when it goes into the tubular fluid

A

binds with a bicarbonate already in the filtrate to form carbonic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

how does this carbonic acid formed get back into the epithelial cell

A

breaks down to form CO2 and H20 which diffuses across apical membrane into cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what drives the secretion of H+ through the apical membrane

A

CO2 partial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

why is the reabsorption of HCO3 known as unorthodox reabsorption

A

the same HCO3- doesn’t cross the epithelium

47
Q

what does secreted H+ bind to when bicarbonate concentration in tubular fluid is low

A

phosphate - the next most plentiful buffer

48
Q

how does excretion of titratable acid (phosphoric acid) and ammonia increase the pH of plasma

A

H+ has been excreted with a net gain of a new bicarbonate ion

49
Q

for every hydrogen ion secreted, how many new bicarbonate ions are made and absorbed into blood

A

one

50
Q

if 40mmol of titratable acid was passed out in the urine, how much new bicarbonate has been created

A

40mmol

51
Q

how do you see how much [H+] has been secreted

A

titrating H+ excreted as phosphoric acid against a strong base

52
Q

if a patient is very acidotic what happens

A

H+ binds to ammonia to form an ammonium ion which is excreted

53
Q

what is the chemical from the liver that is broken down to give ammonia in acidotic conditions

A

glutamine

54
Q

how does ammonia get into the tubular fluid from the epithelial cell

A

diffusion - it is a gas

55
Q

what is the enzyme that breaks down glutamine

A

glutaminase

56
Q

can H+ excreted as ammonium ions be titrated and therefore measured

A

no

57
Q

for every ammonia acid created how many new bicarbonate ions are generated

A

1

58
Q

what 3 things does H+ secretion do

A

drives the reabsorption of bicarbonate ions
forms acid phosphate
makes an ammonium ion

59
Q

what regenerates buffer stores and rids the body of an acid load

A

excretion of titratable acid and ammonium ions

60
Q

what is the range of [HCO3-]

A

23-27 (close to 25)

61
Q

what is the range of PCO2

A

35-45 (close to 40)

62
Q

what is compensation

A

restoration of pH irrespective of what happens to the plasma concentration of bicarbonate and PCO2

63
Q

what is correction

A

restoration of pH and the PCO2/bicarbonate back to normal

64
Q

what happens first in acid base disturbance

A

compensation

65
Q

what 2 processes are involved in the immediate buffering of a pH change

A

immediate dilution of the acid or base in the ECF

buffers present in the blood and ECF

66
Q

what buffers are present in the blood

A

Hb and HCO3-

67
Q

what buffers are present in the ECF

A

HCO3-

68
Q

deoxygenated blood has a higher/lower affinity for H+

A

higher

69
Q

acidosis will ____ the plasma levels of bicarbonate

A

reduce

70
Q

what happens when the stores of buffer are depleted (happens quickly)

A

up to the kidney to replete the stores

71
Q

using the HH equation, a blood gas analyser can measure the __ and ___ allowing the conc of ____ to be measured and the results are shown on a ____

A

pH and PCO2
bicarbonate ions
davenport diagram

72
Q

what causes respiratory acidosis

A

retention of CO2 in the body - hypoventilation

73
Q

give 5 conditions that would result in respiratory acidosis

A 
chronic bronchitis
chronic emphysema
airway restriction
chest injury 
respiratory depression - morphine/GA
74
Q

CO2 retention drives the equilibrium to the

A

right

75
Q

acute retention of CO2 causes levels of H+ to ___ and levels of HCO3- to ____

A

both rise

76
Q

what would indicate uncompensated respiratory acidosis

A

pH < 7.35

PCO2 > 45

77
Q

true/false
there is virtually no extracellular buffering in respiratory disorders. since the cause is respiratory the kidneys must compensate

A

true

78
Q

CO2 retention stimulates what

A

H+ secretion into the filtrate

79
Q

are any bicarbonate ions excreted in the urine in acidosis

A

no - all filtered HCO3- is reabsorbed as H+ is secreted into the urine

80
Q

what happens as H+ continues to be secreted

A

TA and NH4+ are generated which means new bicarbonate ions are added to the blood and acid is excreted out in the urine

81
Q

why does [HCO3-]plasma rise in respiratory acidosis

A

the condition itself - shifting the equation to the right due to high levels of CO2
and as a result of renal compensation introducing new bicarbonate into the blood

82
Q

what is involved in correction of respiratory acidosis

A

lowering the PCO2 by restoration of normal ventilation

83
Q

what causes respiratory alkalosis

A

excess removal of CO2 from the body - hyperventilation

84
Q

give some examples of when respiratory alkalosis might occur

A

fever
panic/hysterical overbreathing
low inspired PO2 at high altitude leading to hyperventilation
brainstem damage

85
Q

excessive CO2 removal drives equilibrium to the

A

left

86
Q

excess removal of CO2 from the body causes levels of H+ to ____ and levels of HCO3- to ___

A

both fall

87
Q

what would indicate uncompensated respiratory alkalosis

A

pH > 7.45

PCO2 < 35

88
Q

how does the kidney compensate for respiratory alkalosis

A

lack of CO2 in the plasma causes a decrease in H+ secretion meaning [H+] goes up
and further lowers the amount of bicarbonate in the plasma

89
Q

is bicarbonate secreted in the urine in respiratory alkalosis

A

yes - secretion of H+ into the tubular fluid is insufficient to reabsorb all of the bicarbonate so even though it is lower in level than normal some is excreted and the urine is alkaline

90
Q

what does correction of respiratory alkalosis require

A

restoration of normal ventilation

91
Q

what is the most common of the acid base imbalances

A

metabolic acidosis

92
Q

what causes metabolic acidosis

A

excess H+ from any source other than CO2

93
Q

what are some examples of causes of metabolic acidosis

A

ingestion of acids or acid producing food
excessive production of H+ e.g. lactic acid during exercise
excessive loss of base e.g. diarrhoea

94
Q

what does metabolic acidosis do to the levels of [H+] and [HCO3-] in the body

A

increases [H+]

decreases [HCO3-]

95
Q

why is [HCO3-] decreased in metabolic acidosis

A

either due to loss from the body

or depleted as a result of buffering excess

96
Q

what indicates uncompensated metabolic acidosis

A

pH < 7.35

HCO3- low

97
Q

what is involved in the compensation of metabolic acidosis

A

respiratory compensation - decrease in plasma pH stimulates peripheral chemoreceptors to increase ventilation and blow off CO2

98
Q

blowing off CO2 moves the equilibrium to the

A

left

99
Q

respiratory compensation by blowing off CO2 causes H+ to ____ and HCO3- to ____

A

both decrease

100
Q

what is involved in correction of metabolic acidosis

A

filtered HCO3 is very low and readily reabsorbed
H+ secretion continues and produces TA and NH4+ generating new HCO3-
kidneys lose H+ and gain HCO3-

101
Q

correction of metabolic acidosis by the kidneys causes the urine to become ___

A

acidic - acid load is excreted

102
Q

why is respiratory compensation essential in metabolic acidosis

A

acid load cannot be excreted immediately

103
Q

how is metabolic alkalosis caused

A

excessive loss of H+ from the body

104
Q

give some examples of situations that would cause metabolic alkalosis

A

loss of HCl from stomach e.g. vomiting
ingestion of alkali or alkali producing food e.g. antacids
aldosterone hypersecretion

105
Q

metabolic alkalosis causes [H+] to ____ and [HCO3-] to ____

A

H+ fall

HCO3- to rise

106
Q

how does metabolic alkalosis cause HCO3- to rise

A

either due to loss of H+ or addition of base

107
Q

what would indicate uncompensated metabolic alkalosis

A

pH > 7.45

HCO3- high

108
Q

how does increased pH from a metabolic source cause respiratory compensation

A

peripheral chemoreceptors detect increased pH and slow ventilation to retain CO2 (PCO2 rises)

109
Q

CO2 retention shifts the equilibrium to the

A

right

110
Q

CO2 retention causes [H+] to ____ and [HCO3-] to ____

A

H+ rises

HCO3- also rises

111
Q

what does renal correction for metabolic alkalosis involve

A

filtered HCO3- load is so large compared to normal that not all of the filtered HCO3- is reabsorbed so is excreted
no TA or NH4+ is generated, no new bicarbonates are formed
[HCO3-] of blood returns to normal

112
Q

renal correction of metabolic alkalosis causes urine to be ….

A

alkaline - bicarbonate is excreted

113
Q

what is harder to compensate for: respiratory acidosis or metabolic acidosis

A

respiratory acidosis - renal compensation takes longer than respiratory compensation

year 2 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions