Test 159  (Ocular anatomy )
1. The following are true about the extraocular muscle fibres:
a. they are poorly fasciculated

b. they are all supplied by single motor end plates

c. they contain a higher ratio of nerve axons to muscle 
    fibres compared with the skeletal muscles

d. the outer (orbital) fibres have a larger diameter than
    the inner (global) fibres.

e. in the orbital zone, the majority of fibres are of the
    fibrillenstruktur type


2. Felderstruktur fibre:
a. produces tonic contraction in response to acetylcholine

b. contains poorly defined myofibrils

c. contains straight Z-line

d. contains grapelike nerve endings

e. has no M-line

3. Fibrillenstruktur fibre:
a. is rich in mitochondria 

b. has well developed sarcomere

c. contains granular synaptic vesicles

d. contains centrally located nuclei

e. is absent in the global zone of the extraocular muscle


4. The following are true about the eyelid:

a. its skin is the thinnest in the body

b. the palpebral aperture can be widened by an 
    additional 2 mm through the use of frontalis.

c. the upper tarsus is about three time higher than the 
    lower tarsus

d. the muscle of Riolan is part of the orbicularis muscle

e. facial nerve palsy causes upper lid retraction


5. Muller cells:
a. are glial cells

b. extend vertically from the inner limiting membrane to 
    the outer plexiform layer

c. have nuclei in the inner nuclear layer

d. contain proteins that bind retinaldehyde

e. produce insulin and growth hormone

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