Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochemistry > Acid-Base Regulation > Flashcards

Acid-Base Regulation Flashcards

1
Q

Define acid

A

A substance that can release a hydrogen ion when dissolved in water

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

Define base

A

A substance that can accept a hydrogen ion

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

Define buffer and give an example of one in the human body

A

A chemical that minimises the change in pH when an acid or base is added to a solution. Carbonic acid

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

Define anion

A

Atoms or groups of atoms that carry a negative charge

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

Define cation

A

Atoms or groups of atoms that carry a positive charge.

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

Features of PaCO2

A

Partial pressure of CO2 in arterial blood
Normal 38-42 mmHg
PaCO2 arterial blood = PaCO2 in alveolar air

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

Features of PaO2

A

Partial pressure of oxygen in arterial blood
Normal is 75-100mmHg

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

Features of bicarbonate and how its measured

A

Anion
Measured indirectly on an arterial blood gas
22-26mEq/L(mmol/L)

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

Role of lungs in Acid-base homeostasis

A

Regulate arterial PCo2 and thus the conc. of dissolved CO2 in blood via changes in alveolar ventilation

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

Role of kidneys Acid-Base homeostasis

A

Regulate HCO3- via changes in renal H+ excretion

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

What are the three components in response to Acid-Base perturbation?

A

1st defence: buffering
2nd defence: respiratory - alteration in arterial pCO2
3rd defence: renal - alteration in HCO3

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

Features of the immediate response: buffering

A

Rapid physico-chemical phenomenon
Buffering of fixed acids by bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Features of the respiratory response: alteration in ventilation

A

Adjustment of the denominator pCO2 by alterations in ventilation is relatively rapid
Increased CO2 excretion due to hyperventilation
Useful physiologically because of its effect on intracellular pH as well as extracellular pH
CO2 crosses cell membrane easily so changes in pCO2 affect pH rapidly
Respond quickly because of the huge amounts of respiratory coif to be excreted

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

Three outcomes of increased CO2 excretion due to hyperventilation

A

1️⃣ Correction of respiratory acidosis
2️⃣ Production of a respiratory alkalosis
3️⃣ Compensation for a metabolic acidosis

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

Features of the renal response: alteration in bicarbonate excretion

A

Much slower process (several days) involves adjustment of bicarbonate excretion by the kidney
Responsible for the excretion of the fixed acids and for compensator changes in plasma [HCO3-] in the presence of respiratory acid-base disorders

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

__________ acid-base disorders change in bicarbonate concentration.

A

Metabolic

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

Explain the association metabolic acid-base disorders and diabetes mellitus

A

Altered intermediary metabolism in the absence of insulin causes a build-up of H+

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

____________ acid-base disorders change in pCO2

A

Respiratory

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

If the primary acid-base disorder is from a _____________ cause, then the kidneys will
compensate (renal compensation), renal mechanisms can bring about metabolic compensation.

A

Respiratory

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

If the primary disorder is from a ________ cause, then the lungs will compensate (respiratory
compensation), hyperventilation or hypoventilation can help: respiratory compensation.

A

Metabolic

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

How long does does respiratory compensation take?

A

12-24 hours

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

How long does renal compensation take?

A

2-5 days

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

Kidneys compensate for respiratory acid-base disturbances by _____________________

A

Adjusting bicarbonate

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

Lungs compensate for metabolic acid-base disturbances by ________________.

A

Adjusting carbonic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Compensatory response to respiratory disorders is two fold:
A fast response due to cell buffering And a significantly slower response due to renal adaptation
26
Compensatory response to metabolic disorders involves only:
An alteration in alveolar ventilation
27
Metabolic acidosis
The primary disorder is a decrease in bicarbonate (HCO3-) concentration
28
Metabolic alkalosis
The primary disorder is an increased bicarbonate (HCO3-).
29
Respiratory acidosis
The primary disorder is an increased PCO2.
30
Respiratory alkalosis
The primary disorder is a decreased PCO2.
31
Metabolic acidosis
H+ elevated Acidosis ⬇️HCO3-
32
Metabolic alkalosis
H+ decreased Alkalosis HCO3- ⬆️
33
Anion gap
The difference between the main cation and the main anions
34
High anion gap acidosis
Renal failure
35
Normal anion gap acidosis
Diarrhoea
36
Two common causes of high anion gap metabolic acidosis
Diabetes ketoacidosis Lactic acidosis
37
Diabetic ketoacidosis
The lack of insulin causes the liver to excrete ketone bodies (beta-hydroxybutyric acid, acetoacetate) for cells to use as fuel. Ketone bodies add H+ to the blood.
38
Lactic acidosis
Hypoxia causes cells to undergo anaerobic metabolism, and excessive lactate is produced. Lactate adds H+ to the blood.
39
Two common causes of normal anion gap metabolic acidosis
Diarrhea (intestinal loss of HCO3-) Renal tubular acidosis (renal loss of HCO3-)
40
How is electroneutrality maintained in normal anion gap metabolic acidosis?
Cl- levels rise to replace the lost HCO3-
41
In ___________________, the normal response of the kidneys is to excrete acid as ammonium.
Metabolic acidosis
42
How do we distinguish RTA from other forms of acidosis?
In RTA, NH4+ excretion is impaired so we can distinguish by measuring the amount of NH4+ present in the urine. Usually done indirectly with the urinary anion gap or urinary osmolal gap.
43
In what conditions is the urinary Osmolal gap preferred?
Urinary pH> 6.5 Polyuria Ketoacidosis Acetaminophen overdose
44
The urinary gap should be _______ in metabolic acidosis because NH4+ is excreted with chloride (NH4+Cl-). A positive gap is a sign of ___ and/or ______________.
Negative RTA Kidney failure
45
The most common cause of ___________________ is vomiting and dehydration.
Metabolic alkalosis
46
_____of H+ and Cl- in gastric fluid raises plasma HCO3-.
Loss
47
Dehydration and potassium loss lead to renal ______ retention which further exacerbates the alkalosis.
HCO3-
48
Metabolic alkalosis is typically driven by 3 processes:
Chloride loss/malabsorption Increased mineralcorticoid activity Low potassium
49
In metabolic alkalosis, the lungs ________ ventilation in order to retain CO2, but the effect is limited by the respiratory stimulatory effects of ________ PaCO2 and ________ PaO2.
Decrease Increased Decreased
50
How is Cl- lost?
Vomitting Nasogastric suction Diuretic use
51
Decreased Cl- absorption occurs in:
Bartter and Gitelman syndrome
52
Decreased Na+ transport through the Na+-Cl- and Na+-K+Cl-Cl- cotransporters promotes…
…promotes Na+-H+ exchange, and HCO3- is retained
53
What causes increased mineralcorticoid activity?
Hypovolemia Cushing’s syndrome Conns syndrome Exogenous steroids Bartters syndrome Licorice ingestion
54
Effects of increased mineralcorticoid activity
Stimulate the H+ pump causing HCO3- to be retained Na+-K+ exchange is also increased and K+ loss is enhanced
55
How is K+ lost?
Vomiting Increased mineralcorticoid activity Diuretic use Chloride deficiency stimulates movement of intracellular K+ into plasma via K+-H+ exchange Increases in intracellular H+ stimulate HCO3- retention
56
How do we distinguish between chloride loss from syndromes associated with excessive mineralcorticoid activity and impaired chloride re absorption?
Check urinary chloride
57
Low spot urinary chloride
Chloride depletion is likely present e.g. vomiting
58
High spot urinary chloride
Excessive mineralcorticoid activity e.g. Conn’s syndrome or impaired chloride absoprtion e.g. Bartter and Gitelman syndromes may be the primary disorder
59
Respiratory acidosis
H+ elevated Acidosis PCO2⬆️
60
Respiratory alkalosis
H+ decreased Alkalosis PCO2⬇️
61
In acute respiratory acidosis why is there no renal compensation?
It takes 48-72 hours for renal compensation to become fully effective
62
The problem in acute respiratory acidosis is…
Alveolar hyperventilation
63
An example of acute uncompensated respiratory acidosis
Choking
64
Example of chronic respiratory acidosis
COAD accompanied with maximal renal compensation
65
In many patients with ______ respiratory conditions, extensive renal compensation will keep the blood [H+] near normal, despite grossly impaired ventilation.
Chronic
66
Features of respiratory alkalosis
Les common No renal compensation Remove cause of hyperventilation Hysterical over breathing Mechanical over-ventilation
67
What happens in a patient with chronic bronchitis who develops renal impairment?
Raised H+ PCO2 will be increased and HCO3- conc will be low, both expected findings in primary respiratory and primary metabolic acidosis

Biochemistry (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions