CSGD Quiz 3 2008

1

Which one of the following statements is correct?


  Long-term instantiation is the most commonly studied form of synaptic plasticity.

  Changes in the strength of connections between glia has been shown in animal models to mediate learning and memory.

  The NMDA and AMPA ionotropic glutamate receptors have been implicated in synaptic plasticity in the mammalian cerebral cortex.

  Classical (Pavlovian) conditioning is an example of declarative (explicit) memory.

  Adult neurons of the mammalian cerebral cortex are unable to generate new synapses.


A is incorrect: Long-term potentiation is the correct term. B is incorrect: Changes in the strength of connections between neurons is important. C is correct. D is incorrect: Classical conditioning involves non-declarative associative memory. E is incorrect: New synapse generation is an important component of LTP.

2

Which one of the following statements relating to the CNS stimulant amphetamine is correct?


  Amphetamine elicits stereotypic behaviour.

  Amphetamine is an appetite stimulant.

  Amphetamine induces hypothermia.

  Amphetamine has local anaesthetic activity.

  Amphetamine inhibits serotonin re-uptake.


A is correct: Amphetamine often 'enhances' habitual behaviour (e.g. readjusting glasses, rubbing ear etc). B is incorrect: Usually suppresses appetite. C is incorrect: Induces hyperthermia (a common factor in amphetamine-related deaths). D is incorrect: This is a feature of cocaine. E is incorrect: Amphetamine stimulates release of noradrenaline from storage vesicles.

3

Which one of the following drug classes are NOT used in the management of mood disorders?


  Inhibitors of serotonin re-uptake.

  Inhibitors of α2-adrenoceptors.

  Inhibitors of monoamine oxidase.

  Inhibitors of noradrenaline uptake.

  Inhibitors of β2-adrenoceptors.

4

Which one of the following statements about the effect of ageing on the genito-urinary tract and function is correct?


  Bladder capacity increases.

  FSH and LH levels decrease.

  There is no change in renal sodium conservation.

  Renal medullary loss is greater than cortical loss.

  There is an increase in nocturnal polyuria.


A is incorrect: Bladder capacity shows a variable decrease (young: ~600mls, old: ~250mls). B is incorrect: FSH and LH increase in both sexes. C is incorrect: There is reduced sodium conservation. D is incorrect: Cortial loss > medullary loss. E is correct: At least partially due to an impaired ability to concentrate urine.

5

Which one of the following statements about falls in older people is most correct?


  Fractured neck of the femur is the most common injury.

  Environmental hazards are the major contributing factor.

  Medications to reduce anxiety, such as diazepam, may reduce the risk of falls.

  Frequent falls warrant Nursing Home admission.

  Fear of falling is the most common consequence.


A is incorrect: Most injuries are soft tissue only. B is incorrect: Many will attribute falls to environment (extrinsic) factors, but intrinsic and behavioural factors are often important contributors. C is incorrect: Many anxiolytics induce drowsiness and a loss of coordination, increasing risk of falls. D is incorrect: Factors contributing to the falls are potentially modifiable; this should be considered first. E is correct: 50% will have subsequent fear of falling even in the absence of significant injury.

6

Which one of the following conditions is most frequently associated with a frequent fluctuation in cognition?


  Alzheimer's disease.

  Depression.

  Parkinson's disease.

  Delirium.

  Mild cognitive impairment.


Delirium is the most acute of the three "D's"; the progression of the others is usually slower and steadier.

7

Which one of the following drugs should never be used in people over the age of 80 years?


  Carbamazepine.

  Amitriptyline.

  Temazepam.

  Indomethacin.

  Flunitrazepam.

8

Which one of the following statements about genes or chromosomes is correct?


  There are imprinted genes on most of the 23 pairs of chromosomes.

  Uniparental disomy is the most common cause of Prader-Willi syndrome.

  Parthenogenesis refers to an embryo formed which contains all 46 chromosomes from the father.

  X-inactivation is an example of an epigenetic event.

  Changes to imprinted genes on chromosome 15q are associated with Beckwith-Widemann syndrome.


A is incorrect: Imprinted genes tend to be clustered (the "Human Imprinting Map" in the notes shows imprinted genes on only 9/23 chromosomal pairs). B is incorrect: Prader-Willi syndrome is most commonly caused by paternal microdeletions, leading to a loss of heterozygosity (70%). UPD accounts for only 25%. C is incorrect: This is androgenesis. D is correct: X inactivation involves a number of epigenetic mechanisms, e.g. DNA methylation. E is incorrect: Changes to imprinted genes on chromosome 15q are associated with Prader-Willi and Angelmann syndromes. Beckwith-Widemann involves chromosome 11p.

9

Which one of the following is the mechanism by which the HOX genes control embryonic development?


  Signal induction between neighbouring cells.

  Providing cells with positional information.

  Directly activating structural genes, which then induce cellular differentiation.

  Responding to homeotic transformations.

  Defining the dorsal versus the ventral axis.


A is incorrect: HOX genes are transcription factors, not morphogens. B is correct. C is incorrect: Morphogens (signalling molecules) are the more direct mediators of structural gene regulation. D is incorrect: Changes to HOX genes CAUSE homeotic transformations. E is incorrect: HOX genes encode positional identity along the rostral/caudal axis.

10

Which one of the following statements about teratology is correct?


  Chorionic villus sampling (CVS) carries a post-procedure miscarriage risk of approximately 3%.

  CVS is the preferred procedure in prenatal diagnosis prior to 10 weeks of gestation.

  Vascular disruption defects are a recognised complication of CVS.

  Teratogens are harmful at all gestations.

  A dose-response relationship has been established for most teratogens.


A is incorrect: The miscarriage risk of CVS is approximately 1%. B is incorrect: CVS is usually performed after 12 weeks gestation. C is correct. D is incorrect: Not all teratogens are harmful at all periods of gestation; most are more harmful at earlier phases (e.g. during organogenesis). E is incorrect: Dose-dependence is one of Wilson's principles, but it would appear that it has not been established in the majority of substances considered 'teratogens'.