Past MCQs for Paper 2   (Feb, 1992)
1. The electro-oculogram:
a. measures the standing potential between the front and the back 
   of the eye
b. the normal response in a dark adapted state is twice as big as 
    that in light
c. is of particular use in the diagnosis of Best's disease
d. is of value in early stages of most retinal degeneration
e. the normal range of Arden values is between 175 and 220%

2. The primary absorbers of visual light in the retina and choroid are:

a. retinal ganglion cells
b. macular xanthophyll
c. melanin
d. photoreceptors
e. haemoglobin

3. The blood retinal barrier:

a. the outer blood retina barrier is formed by RPE cells and their 
b. the basement membrane of the retinal capillaries is a major 
    component of the inner blood retina barrier
c. the blood retinal barrier is typically defective in the immediate 
    peripapillary region
d. the retinal vascular endothelial cells can actively transport fluid and 
    anions from the extracellular space fo the retina into the circulation
e. inhalation of 10% carbon dioxide causes rapid breakdown of the 
   inner blood retina barrier

4. Human aqueous contains higher levels than plasma of :

a. zinc
b. chloride
c. ascorbic acid
d. hyaluronidase
e. bata-crystallin 
5. Saccadic movements of the eye:
a. are typically present in infants at birth
b. develop in infants before smooth pursuit movements appear
c. have a velocity of about 500 degrees per second
d. originate in the ipsilateral frontal lobe of the brain
e. act independently of the vestibular system

6. Visual pigment dynamics:

a. molecules of rhodopsin are on the surface of the lipid bilayer of 
    the disc membrane
b. 11 cis-retinal fits into hydrophobic cleft in visual pigment molecule
c. visual excitation initiation occurs by isomerisation of 11 cis-retinal 
    into all-trans retinol
d. opsin is responsive to bright light stimulation
e. during photoreceptor renewal new opsin molecules are added to 
    the outer segments

7. The intraocular pressure can fluctuate:

a. seasonally
b. diurnally
c. with eye movements 
d. in optic neuritis
e. with fluid intake

8. The tear film:

a. contributes to the refractive function
b. is stabilized by the mucus layer
c. is partly formed form the Meibomian gland
d. is 100um thick
e. its normal break-up time is 5-15 seconds

9. Concerning colour vision and its assessment:

a. the axis of colour vision loss in protonopia using the 
    Farnsworth-Munsell 100 Hue test passes through the pigments 
    red and green on the colour circle
b. the Ishihara pseudo-isochromatic plates can be used to detect 
c. the Nagel-anomaloscope is used to detect red/green colour 
d. the Farnsworth Panel D 15 test relies on colour confusion across 
    the colour circle for the detection of an abnormality in colour vision
e. the Lanthony desaturated Panel D 15 test is less sensitive than the 
    Farnsworth Panel D15 test

10. In  the ageing lens:

a. there is a decrease in insoluble albumin
b. there is an increase in heavy molecular weight crystallin
c. is aggregation of a-crystallin
d. there is a decrease in b-crystallin
e. there is an increase in protein soluble in urea

11. In the first stages of bleaching of rhodopsin the following are formed:

a. opsin
b. all trans-retinal isomers
c. 11 cis-retinal isomers
d. intermediate products including metarhodopsin
e. vitamin A

12. Accommodation:

a. is abolished by sympathomimetic drugs
b. produces an increased curvature of the anterior surface of the lens
c. is dependent on elasticity of the lens capsule
d. is regulated with the help of chromatic aberration
e. is essential for appreciation of stereopsis

13. The RPE cells:

a. transport retinol binding protein from blood to subretinal space
b. esterify and store excess retinol
c. are independent units and do not communicate electrically 
    or metabolically with each other
d. are secured laterally to each other by tight junction
e. dehydrate the subretinal space and create forces binding 
    themselves to neurosensotry retina

14. The study of eye movements has shown:

a. saccadic movements have a latency of about 200 msec
b. smooth pursuit movements have a maximum velocity of about 40 
    degrees per second
c. smooth pursuit movements cannot be executed without stimulus of 
    target motion
d. the inferior colliculus is important centre for visuomotor processing
e. flocculus has a role in adjusting the amplitude of the 
    vestibulo-ocular reflex
15. Stereopsis is produced by:
a. horizontal retinal disparity
b. an intact corpus callosum
c. polarized light
d. microsaccadic oscillations
e. Fox-Talbot effect

16. In relation to action of light on the eye:

a. equal amounts of radiant energy provide equal visual responses 
    irrespective of wavelength
b. human has a maximum sensitivity at 453 nm in bright light
c. in dark adaptation the initial phase is attributed to retraction of 
   processes of the RPE
d. the retina cannot dark adapt if there is damage to the macula
e. it takes 7 photons to evoke a visual sensation in a single rod

17. The cones:

a. are responsible f or colour vision
b. are more sensitive to light than rods
c. are associated with a higher visual acuity than rods
d. have their function more impaired than rods by vitamin A 
e. are longer and thinner in the peripheral retina than in the central 

18. During accommodation for near:

a. the spherical aberration of the eye increases
b. the ciliary muscle relaxes
c. the field of vision decreases
d. the amount of light entering the eye increases
e. the thickness of the lens increases

19. With respect to motor neurones:

a. each a motor neurone supplies a single muscle fibre
b. those motor neurones which take part in spinal reflexes are not 
    involved in voluntary movements
c. when two reflexes which reinforce each other are elicited 
    together, their joint effect may be greater than the sum of their 
    individual effects
d. when two reflexes which reinforce each other are elicited together
    their joint effect may be less than the sum of their individual 
e. when a muscle is activated its b motor neurones usually fire as 
    well as its a-motor neurones

20. With respect to sensory pathways:

a. receptive field properties of a sensory neurone define the patterns of stimulation to which  it responds best
b. lateral inhibition contributes to the receptive field properties of 
    neurones in visual, auditory and somatosensory pathways
c. neurones in dorsal columns have clearly defined receptive fields
d. all sensory fibres entering the spinal cord cross the midline within 
    a few segments of point at which they enter
e. sensory neurones which are involved in spinal reflex arcs also 
    contribute to ascending sensory pathways
21. With respect to CNS organization:
a. most sensory pathways relay in the thalamus on their way to the 
b. sensory fibres enter the spinal cords by the dorsal roots
c. most motor pathways synapse on interneurones in the spinal cord
d. the left hand side of the brain receives information mainly from the 
    left hand side of the body and vice versa
e. cell bodies of spinal motor neurones lie outside the spinal cord

22. Compliant of lungs:

a. may be expressed as volume change per unit change in 
    intrapleural pressure
b. is greater if the lung is stiff
c. is indirectly proportional to surface tension forces in the lungs
d. is affected more by surface tension forces than elastic recoil at 
    low lung volumes
e. is dependent upon lung volume

23. Ventilation is stimulated by:

a. fall in arterial oxygen pressure acting on central chemoreceptors
b. increased pH of arterial blood
c. increase pH of cerebrospinal fluid
d. interruption of the brain stem  at the junction between the spinal 
    cord and the medulla oblongata
e. excitation of mechanoreceptors in the limb joints

24. Which of the following alone will enable determination of the plasma volume in 
       the body:

a. Evan's blue
b. radioactive sodium
c. haematocrite
d. red cell count
e. deuterium oxide

25. The pupil:

a. is dilated by the nicotinic action of atropine
b. is constricted by a blocking action of thymoxamine
c. is dilated by the muscarinic action of cocaine
d. is constricted by 0.1% pilocarpine in Adie's pupil
e. demonstrates denervation sensitivity in upper motor neurone 
    Horner's syndrome

26. The following drugs give rise to impairment of accommodation:

a. pilocarpine
b. atropine
c. thymoxamine
d. phenylephrine
e. major tranquillizers

27. In administration of ophthalmic preparations:

a. acetazolamide should be avoided in patients with renal calculi
b. timolol maleate is a selective b blocker
c. systemic side effects of pilocarpine drops are dryness of mouth 
    and lack of sweating
d. gentamicin sulphate has no toxic effects on the cornea
e. eumovate drugs have less effect on IOP than dexamethasone 
28. Systemically administrated chloroquine:
a. is safer than hydroxychloroquine at equivalent dose
b. can cause corneal depositions of the drug
c. causes reversible toxic maculopathy
d. can cause posterior subcapsular cataract
e. causes abnormal dark adaptation

29. Which of the following statement is true:

a. dichlorphenamide is a carbonic anhydrase inhibitor
b. physostigmine is a cholinesterase inhibitor
c. cocaine eyedrops cause miosis
d. physostimgine eyedrops cause miosis
e. atropine is an anticholinergic drug

30. Recognized adverse effects of systemic carbonic anhydrase inhibitors are:

a. anorexia
b. depression
c. increased libido
d. blood dyscrasiaa
e. urolithiasis
31. Acetazolamide causes:
a. metabolic acidosis
b. hypernatraemia
c. hyperkalaemia
d. renal calculi
e. inhibition of carbonic anhydrase

32. When applied topically to the eye, anticholinesterases:

a. relax the sphincter pupillae muscle
b. cause conjunctival hyperaemia
c. contract the ciliary muscle
d. raise the IOP
e. may produce systemic effect

33. H--receptor blockers:

a. have an arousing action in the CNS
b. are used as anti-emetics
c. include mepyramine
d. may have muscarinic receptor blocking action
e. prevent histamine induced gastric secretion

34. The following drugs may aggrevate or cause gastrointestinal ulceration:

a. aspirin
b. paracetamol
c. codeine phosphate
d. phyenylbutazone
e. indomethacine

35. At the adrenergic synapse, the concentration of noradrenaline in the synaptic 
      cleft is:

a. decreased by MAO inhibitors
b. increased by noradrenaline reuptake blockers
c. increased by partial agonist of noradrenaline receptors
d. increased by noradrenaline receptor blockers
e. mainly controlled by activity of the enzyme COMT

36. Renal clearance of acidic drugs may be delayed by:

a. alkalinizing the urine
b. administration of probenicid
c. their displacement from plasma protein binding sites
d. sequestration in fat
e. respiratory acidosis

37. Clinically significant anticoagulant effect s of warfarin are diminished by 

a. barbiturates form chemical complexes with warfarin
b. induction of liver enzymes
c. competition for plasma protein binding sites
d. competition for renal secretion
e. barbiturate reduces the gastrointestinal absorption of warfarin

38. Case-control study:

a. is an example of interventional epidemiological study
b. provides knowledge concerning how much disease exists in a 
c. requires vigorous study design and data analysis
d. must be performed in population of more than one million
e. is usually prompted by a descriptive study

39. The respiratory system:

a. the vital capacity is the maximal volume to which lungs can expand
b. the functional residual capacity is the expired residual volume plus 
    the residual volume
c. Herring-Breuer reflex is transmitted via the tractus solitarius
d. the blood PCO2 has more an effect on the pH of the CSF than 
    the blood pH
e. the chemoreceptors for control of respiratory activity are located 
    in the carotid bodies

40. Electrolytes:

a. bicarbonate is present intracellular and extracellular
b. the major extracellular ion is chloride
c. intracellular protein functions as a cation
d. the distribution of Ca2+ between intracellular and extracellular 
    fluid is influenced by membrane bound enzyme.
e. ammonium is the main buffer in the serum
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