SAQs Flashcards

1
Q

What is complementary

A

when drugs are used together, the shortcomings are covered

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2
Q

What drugs do CYP2E1 metabolise?

A

volatile agents - sevo

panadol

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3
Q

What is pKa of midazolam

A

6.5

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4
Q

How is midazlolam excreted?

A

Metabolites - a-OH-midazolam, oxazepam

Metabolites further glucuronised then excreted in urine

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5
Q

What structures are lateral to the vocal cords?

A

quadrangular membrane then aryepiglottic folds

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6
Q

What is Volume of distribution

A

the apparent volume for which a drug is dispersed into evenly to provide the observed plasma concentration

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7
Q

How does metformin cause lactic acidosis?

A

Inhibition of complex 1 electron transport chain.

increase anaerobic metabolism -> lactate production

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8
Q

Describe the pharmaceutical disadvantage of xenon

A

expensive
high density and viscosity may increase airway resistance
inefficient storage in gas phase at room temp

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9
Q

What is the MAC of isoflurane and enflurane?

A

iso 1.2
enf 1.6

iso more potent

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10
Q

For optical isomers with absolute atomic number nomenclature, how are the atoms oriented?

A
lowest number pointing to back. 
Define sinister (anti-clockwise), or rectus (clockwise) in descending atomic number
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11
Q

What is an example of geometric isomer?

A

mivacurium, with 3 isomers

cis-cis, cis-tran, tran-tran

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12
Q

Define enantiomer

A

stereoisomers that mirror image of each other

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13
Q

What are the cough receptors sensitive to and where are they located?

A

chemical or mechanical stimuli

Mainly on the posterior wall of trachea, pharynx and carina. Receptors less abundant in distal airway

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14
Q

What are the sites of efferent neural innervation for cough reflex?

A

NTS -> dorsal vagal nucleus, nucleus ambiguous

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15
Q

which vocal muscles cause vocal cord adduction with cough reflex

A

interarytenoids

lateral cricoarytenoids

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16
Q

Which vocal muscle cause vocal cord abduction and release of air with cough reflex?

A

posterior cricoarytenoids

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17
Q

What are the three complement cascades?

A

classic (C1QRS -> C3 convertase)
alternative
lectin

18
Q

Why does a neonatal rib cage collapse in on expiration?

A

Cartilagenous rib cage, decrease outward recoil

almost all diaphragm breathing -> exhale -> reduce intrathoracic pressure -> atmospheric pressure pushes inward

19
Q

Describe the chest wall compliance of neonates

A

lower static compliance mainly due to increased alveolar resistance from lack of surfactant

Chest wall has very high compliance, 3x more than lung. Not sufficiently rigid to sustain high inspiratory pressure
- Neonatal chest wall can collapse in on deep inspiration

20
Q

Why do neonates take very small tidal volumes?

A

High resistance of alveoli, low static compliance

Cartilagenous chest wall which collapses in on deep inspiration

21
Q

How is neonatal gas exchange capacity different to adults

A

High physiological shunt up to 25% from patent ductus arteriosus

High Hb concentration up to 190g/L

Foetal Hb has greater affinity, left shift

22
Q

What are the complications of oxygen therapy in neonates

A

retinopathy

bronchopulmonary dysplasia

23
Q

How is control of ventilation different in neonates?

A

Immature resp centres - frequent periodic apnoea

PCO2 ventilatory response less steep.
In the presence of hypoxia, PCO2 response is blunted further -> can cause low MV

24
Q

How does Henry’s law relate temperature and solubility

A

Henry’s Law: solubility proportional to partial pressure

Amount dissolved = solubility coefficient x partial pressure

solubility is inversely proportional to temperature
- Lower the temp, higher the solubility, higher the amount dissolved, and lower the partial pressure

25
Q

How much does CO2 reduce per degree of temperature drop?

A

2mmHg per degree

26
Q

What is the rationale of alpha stat?

A

intracellular protein buffer alters the intracellular p neutrality with pH change across range of temperature.

Setting the temp at 37 ensures normal enzymic function, as introduction of respiratory alkalosis may cause a change

27
Q

Important structures of mitochondria?

A

2 membranes

  • outer with pores
  • inner without pores

2 compartments

  • Intermembrane space or outer compartment
  • Matrix space or inner compartment
28
Q

How is the inner membrane organised (?increase surface area)

A

cristae

ATP synthase molecules on the inner surface

29
Q

Characteristics of the outer membrane

A

Permits relatively unobstructed movement of molecules in either direction via voltage-gated anion channels

30
Q

Why is the inter membranous space much more acidic than matrix?

A

H+ pumped out -> gradient inward to generate ATP

31
Q

What energy sources are imported into mitochondrial matrix?

A

pyruvate and fatty acids

32
Q

How much energy (in ATP) does 1 unit glucose generate?

A

36 ATPs

Glycolysis - 2 ATP, 2 NADH
Pyruvate -> acetylCoa -> 2 NADH (+2CO2)
Kreb - 2 ATP, 6NADH, 2 FADH2 (+4CO2)
ETC - 10 NADH, 2 FADH2 -> 34 ATPs

33
Q

What are some of the non-metabolic roles of mitochondria?

A
  1. cellular apoptosis, release of cytochrome upon apoptotic trigger
  2. Sequestration of calcium to maintain homeostasis
  3. Haem synthesis
  4. Urea cycle: convert product of ammonia to L-citrulline
  5. Immune responses, reactive O2 species
34
Q

What is Novoseven?

A

activated factor 7a

given in addition to prothrombinex only if persistent haemorrhage despite all other efforts

35
Q

Define tolerance

A

decreased response to a drug with repeated long term use.

36
Q

Respiratory effects of opioid?

A
  1. Effect on pre-Botzinger complex, direct depression and disrupts resp pattern -> prolonged pauses between breaths
  2. Right shift of PaCO2 curve
  3. Depression of airway reflex
  4. Bronchospasm via histamine release
37
Q

CNS effects of opioid

A
  1. reduced in neurotransmitter release in reticular activating system -> sedation -> delirium
  2. Seizures from metabolites of pethidine
  3. Miosis -> excitatory action at Edinger-Westphal nucleus
  4. N/V -> opioid receptors at vomiting centre and CTZ
38
Q

Theophylline MoA?

A

inhibitor of adenosine receptor and facilitates release of endogenous catecholamine from adrenal medulla

inhibitor phosphodiesterase -> increase cGMP and cAMP

39
Q

What kind of GCPRs are muscarinic receptors?

A

M1, 3, 5, -> Gq

M2 ,4 -> Gi

40
Q

What is the definition of an exponential function?

A

any function that takes the form
f(x) = a^x

where a is the base, greater than zero and not 1
When the base is Euler’s number ,the function is said to be a natural exponential function