Biochemistry

Question 1

What is being regulated in acid-base balance?

Answer 1

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

Question 2

How can H+ be buffered?

Answer 2

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

Question 3

Why will the bicarbonate system never reach equilibrium?

Answer 3

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

Question 4

What is the H+ conc proportional to?

Answer 4

The ratio of pCO2/HCO3-

Question 5

What is acidosis?

Answer 5

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

Question 6

What is alkalosis?

Answer 6

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

Question 7

What is pCO2?

Answer 7

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

Question 8

What is HCO3-?

Answer 8

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

Question 9

What is respiratory acidosis?

Answer 9

An increase in H+ conc due to an increased pCO2

Question 10

What is respiratory alkalosis?

Answer 10

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

Question 11

What is metabolic acidosis?

Answer 11

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

Question 12

What is metabolic alkalosis?

Answer 12

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

Question 13

What happens if there is too much H+?

Answer 13

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

Question 14

What happens if there is too much CO2?

Answer 14

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+

Question 15

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

Answer 15

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

Question 16

What are some causes of respiratory alkalosis?

Answer 16

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

Question 17

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

Answer 17

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

Question 18

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

Answer 18

Loss of H+ due to vomit
Alkali ingestion
Potassium deficiency

Question 19

What are the artieral blood gases?

Answer 19

H+
pCO2
HCO3-
pO2

Question 20

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

Answer 20

CK - creatnine kinase

Question 21

What can be used to detect heart damage?

Answer 21

Troponin

Question 22

What can be used to detect pancreas damage?

Answer 22

Amylase

Question 23

What can be used to detect bone damage?

Answer 23

Alk Phos

Question 24

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

Answer 24

AST and LDH

Question 25

What can be used to detect liver damage?

Answer 25

ALT
Alk Phos
Gamma GT

Question 26

What are the two terms used to describe biochemistry tests?

Answer 26

Accuracy

Precision

Question 27

What is a reference interval?

Answer 27

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

Question 28

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

Answer 28

False positive
False negative
True positive
True negative

Question 29

What is senstivity in the context of an MI?

Answer 29

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

Question 30

What is specificty in the context of MI?

Answer 30

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

Question 31

What is the positive predictive value?

Answer 31

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

Question 32

What is the negative predictive value?

Answer 32

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

Question 33

What is prevalance?

Answer 33

The % of total people tester who have an MI

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

Question 34

What are the ABG’s for PaCO2?

Answer 34

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

Question 35

What are the ABG’s for bicarb?

Answer 35

A low bicarb indicates metabolic acidosis

A normal/high bicarb indicates metabolic alkalosis