1. The Stiles Crawford effect:
a. depends on tight packing of the lens fibres
b. depends on transparency of the aqueous humour
c. depends on pupil constriction
d. depends on infra red radiation
e. is a function of cone microanatomy
2. Vitamin A:
a. is combined with opsin in the cis and trans forms
b. retinaldehyde is converted to retinene
c. is found in root crop products
d. is converted in the small intestine to an absorbable
form
e. is stored in RPE cells
3. Amblyopia:
a. is produced in kittens by raising them in an
environment with vertical stripes
b. is greater in alternating rather than unilateral
strabismus
c. is a common management in congenital cataract
d. produces crowding phenomenon
e. can result even when there is obvious strabismus
4. The electro-oculogram:
a. is easily produced in the anaesthetized subject
b. depends on normal RPE
c. is a product of fundal and corneal function
d. is an absolute value in microvolts
e. normally the maximal dark response exceeds the
light response
5. The cones:
a. are responsible for light sensitivity
b. are not found in the peripheral retina
c. contain visual pigments containing iodopsin
d. packing determines the degree of resolution
e. overlie the optic nerve head
6. Accommodation:
a. results from ciliary muscle relaxation
b. results in spherical aberration
c. the pupil constricts
d. there is increased depth of field
e. more light reaches the retina
7. Pupil constriction:
a. is sympathetically mediated
b. spherical aberration is reduced
c. is a monosynaptic reflex
d. occurs in Horner's syndrome
e. can be blocked by cycloplegic
8. Digitalis:
a. inhibits vagal activity
b. alters automaticity of cardiac tissue
c. increases the time for repolarization
d. if given in atrial flutter can cause arrhythmia
e. toxicity is potentiated by hyperkalaemia
9. Acetazolamine:
a. can cause serious metabolic acidosis
b. increases the conversion of bicarbonate ions to
water and carbon dioxide
c. may cause perioral paraesthesia
d. increases intracranial pressure
e. was originally developed as a diuretic
10. Propanolol:
a. can cause skin vessel dilatation
b. increases cardiac output
c. causes bronchodilatation
d. increases exercise tolerance in angina
e. lowers intraocular pressure
11. The vasomotor centre:
a. if the lateral part of the vasomotor is stimulated
vasoconstriction results
b. the Herring Breur reflex passes via the tractus
solitarius
c. if the pCO2 increase the blood pressure rises
12. In DNA:
a. there are equal amounts of purine and pyrimidine
bases
b. purine and pyrimidine bases are joined by covalent
bonds
c. introns exceed exons
d. histones mark excision areas
e. in RNA uracil substitutes for guanine
13. Colour blindness:
a. the red green gene is on the long arm of the X
chromosome
b. the blue visual pigment is coded for on the X
chromosome
c. pigment opsins are coded by introns on
chromosome 3
d. red green colour blindness is always X-linked
e. the colour blind patient has normal visual acuity
14. Eye movements:
a. saccades have a latency of 200 ms
b. smooth pursuit movements have a maximum velocity
of 40 degrees a second
c. accommodation can only occur with defined contours
d. vergence is required for stereopsis
e. accommodation is necessary for pursuit movements
15. True or false:
a. hyaluronic acid is a branched long chain
mucopolysaccharide
b. heparin is produced by macrophages
c. hyponatraemia results in increased contractility of the
heart
d. chloride ions are found in greater concentration
intracellularly
e. potassium is the main intracellular cation
16. True or false:
a. bicarbonate ions are found inside cells
b. beta blockers increase lacrimal secretion
c. pilocarpine increase lacrimal secretion
d. deep petrosal nerve is responsible for lacrimal
secretion
e. major transquilisers decrease lacrimal secretion
17. True or false:
a. if saline solution of 1.5% is applied corneal thickness
decreases
b. light wavelengths of less than 300 nm cause corneal
damage
c. glycosaminoglycans contain galactosamine or
glucosamine
d. the lens can operate via the pentose shunt
e. the lens can function in the absence of oxygen if there is adequate
supply of glucose
18. True or false:
a. the cochlear nerve is a bipolar neurone with a central
process that projects to the medial and lateral
cochlear nuclei
b. the organ of Corti contains endolymph
c. 200 Hz detected at the base of the cochlear
d. impulses are transmitted form the cochlear to the
ipsilateral cortex
e. impulses are also transmitted to contralateral cortex
19. Acidic drug excretion:
a. is decreased in alkaline urine
b. is decreased with probencid
c. can be delayed in respiratory acidosis
20. True or false:
a. cell proteins act as cations
b. topical drugs have to be water soluble to cross the
cornea
c. melanosomes are found in greater concentration in
the apices of the ROE cells
d. T4 and T3 are produced by thyroid cuboidal cells
e. aqueous is formed more by secretion than by
ultrafiltration
21. Hormones:
a. are usually proteins
b. activate cyclic AMP
c. usually bind to membrane receptors
22. Aqueous::
a. contains fibrinolytics
b. contains prostaglandins
c. contains high concentrations of vitamin C
23. True or false:
a. myelination increases the speed of conductance
b. the outside of a resting nerve is negative with respect
to the inside.
c. the upstroke of the action potential is due to an
increase in sodium conductance
24. Fluorescein:
a. absorbs blue light and emits green
b. is mainly protein bound
c. has maximal absorption at 590 nm
d. is fully excreted within 24 hours
25. Eicosonaids:
a. are 22 carbon chain fatty acids
b. are leukotriene precursors
c. indomethacin can block the production of
prostaglandins and thromboxane.