Biochemistry Flashcards

1
Q

What is being regulated in acid-base balance?

A

Hydrogen ion concentration
This is because the acid-base conc of the cell is important. If it is too acidic, the cell will slow down metabolically and won’t function properly

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2
Q

How can H+ be buffered?

A

Can bind with bicarbonate to find CO2 and H20
Can bind with haemoglobin to form HHB
Can find with a hydrogen phosphate ion to form phosphoric acid
Can bind with ammonia to form ammonium

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3
Q

Why will the bicarbonate system never reach equilibrium?

A

Lungs blow off CO2 which means it never reaches equilbrium
H+ + HCO3- goes to H2CO3 which goes to CO2 + H2O
The only limit in the bicarb system is the concentration of bicarbonate

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4
Q

What is the H+ conc proportional to?

A

The ratio of pCO2/HCO3-

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5
Q

What is acidosis?

A

An increase in H+ or a process tending to cause an increase in H+

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6
Q

What is alkalosis?

A

A decrease in H+ concentration, or a process tending to cause a decrease in H+

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7
Q

What is pCO2?

A

The respiratory component - in respiratory the primary change is in pCO2

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8
Q

What is HCO3-?

A

The metabolic component, in metabolic problems the primary change is in HCO3-. If there is too much acid, then HCO3- will be mopped up

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9
Q

What is respiratory acidosis?

A

An increase in H+ conc due to an increased pCO2

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10
Q

What is respiratory alkalosis?

A

A decrease in H+ conc due to decreased levels of pCO2

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11
Q

What is metabolic acidosis?

A

An increase in H+ conc due to decreased levels of HCO3-

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12
Q

What is metabolic alkalosis?

A

A decrease in H+ conc due to an increase in HCO3-

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13
Q

What happens if there is too much H+?

A

The equation will shift to the right and more carbon dioxide will be produced and then excreted via the lungs. The H+ will mop up the excess bicarb and cause lactic aciodosis
Lungs will blow off CO2

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14
Q

What happens if there is too much CO2?

A

If there is too much CO2 the equilibrium will shift to the left to maintain the equilbrium and therefore more H+ will be produced
Kidneys get rid of H+

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15
Q

What are the causes of respiratory acidosis ( increased H+ and increased pCO2)

A

Choking - cannot get rid of CO2 so cell will start to go through anaerobic metabolism
Bronchopneumonia
COPD

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16
Q

What are some causes of respiratory alkalosis?

A

Hysterical breathing
Mechanical over-ventilation - too much CO2 excreted by lungs
Raised intercranial pressure - stimulates the resp center and will drive excess breathing

17
Q

What are some causes of metabolic acidosis (Increased H+ conc, decreased HCO3- conc)

A

Impaired H+ excretion
Increased H+ production or ingestion
Loss of HCO3-

18
Q

What are some causes of metabolic alkalosis? Decreased H+ conc, increased HCO3- conc

A

Loss of H+ due to vomit
Alkali ingestion
Potassium deficiency

19
Q

What are the artieral blood gases?

A

H+
pCO2
HCO3-
pO2

20
Q

What can be used to asses muscle function (not cardiac)

A

CK - creatnine kinase

21
Q

What can be used to detect heart damage?

A

Troponin

22
Q

What can be used to detect pancreas damage?

A

Amylase

23
Q

What can be used to detect bone damage?

A

Alk Phos

24
Q

What can be used to detect blood (erythryctye) damage?

A

AST and LDH

25
Q

What can be used to detect liver damage?

A

ALT
Alk Phos
Gamma GT

26
Q

What are the two terms used to describe biochemistry tests?

A

Accuracy

Precision

27
Q

What is a reference interval?

A

If we measure something in a population or sample of people, there will be a spread of results. In statistical terms there will be a central tendency and a scatter around that central tendency. If you were to measure the same thing in a population or sample of patients with a particular diagnosis, you would get a spread round a different central tendency. There is usually some overlap between the results you get in healthy people and patients with the disease of interest. The extent of this overlap helps to determine how good the test is

28
Q

What can be measured to see how good a test is?

A

False positive
False negative
True positive
True negative

29
Q

What is senstivity in the context of an MI?

A

The % of people with an MI that have a high CK (positive test)
True positive / (True positive + Fase negative)

30
Q

What is specificty in the context of MI?

A

The % of healthy people (without MI) that have a normal CK (negative test)
True negative / (True negative + False Positive)

31
Q

What is the positive predictive value?

A

The percentage of people with a high CK (positive test) who have an MI
True positive / (True positive + False Positive)

32
Q

What is the negative predictive value?

A

The percentage of people with a normal CK who don’t have an MI
True negative / (True negative + False negative)

33
Q

What is prevalance?

A

The % of total people tester who have an MI

True positive + / (True positive + False negative + True negative + False positive)

34
Q

What are the ABG’s for PaCO2?

A

High PaCO2 indicates respiratory acidosis
Low PaCO2 indicates respiratory alkalosis
The body will compensate to metabolic alkalosis by raising the PaCO2
The body will compensate to metabolic acidosis by lowering the PaCO2

35
Q

What are the ABG’s for bicarb?

A

A low bicarb indicates metabolic acidosis

A normal/high bicarb indicates metabolic alkalosis