1. The following structures enter the circle of Zinn EXCEPT:
a. abducent nerve
b. inferior branch of the oculomotor nerve
c. superior branch of the oculomotor nerve
d. trochlear nerve
e. nasociliary nerve
4 nerves pass through the circle of Zinn ie. abducent nerve,
inferior and superior branches of the oculomotor nerve and
the nasociliary nerve.
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2. The inferior branch of the oculomotor nerve supplies the following
structures EXCEPT:
a. ciliary body
b. dilator pupillae of the iris
c. medial rectus
d. inferior oblique muscle
e. inferior rectus
Dilator pupillae is supplied by the sympathetic nerve via the nasociliary
nerve.
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3. The inferior orbital floor is made up of:
a. frontal and maxillary bone
b. sphenoid and maxillary bone
c. lacrimal, maxillary and zygoma
d. maxillary, zygoma and palatine
e. palatine, sphenoid and maxillary bone
The orbital floor is formed primarily by the maxillary bone,
with contributions from the zygoma and the palatine bones.
4. Features seen when the cervical sympathetic ganglia are damaged
on one side of the body include the following EXCEPT:
a. low intraocular pressure
b. anhydrosis
c. failure of the pupil to react to light
d. paralysis of the Muller's muscle
e. updrawing of the lower eyelid
Horner's syndrome causes miosis but the pupil can still react
to light which is mediated by the parasympathetic autonomic
nervous system.
5. Which of the following statement is TRUE about the cones?
a. they are found only in the macula
b. absence of red cones results in deutronopia
c. all the cones are coded by DNA found on the X-chromosome
d. blue cones are the least common amongst the three types of cones
e. the ratio of cones to rods is 1:10
Cones are also found outside the macula. Absence of red cones
results in protanopia. Red and green receptors are coded by DNA
on the sex chromosome ie. X-chromosome but the blue is
on Chromosome 7. The ratio of cones to rods is 1:20.