11.The corneal stroma:
a. has collagen fibres arranged in lamellae that are 4 microns
thick
b. consists mainly of type I collagen
c. is transparent due to its compact, regular arrangement of lamellae
and its positively charged Glycosaminoglycans matrix
d. contains the occasional fibroblast, macrophage, lymphocyte and
poly-morphonuclear lymphocyte
e. consists of the GAGs, Chondroitin4-sulphate, Keratan sulphate
and hyaluronic acid
12. The corneal endothelium:
a. has a basement membrane
b. despite being metabolically active does not reproduce by mitosis
c. are all hexagonal in shape for maximal stability and interdigitation
of plasma membranes
d. terminates at the trabecular meshwork
e. is the layer most responsible for maintaining corneal dehydration
13. The cornea is supplied:
a. with oxygen at its centre from the tear film only
b. with capillary blood from the anterior ciliary vessels of the
conjunctiva and sclera
c. by the short ciliary nerves, branches of the ophthalmic division
of
trigeminal nerve
d. by nerves that enter the orbit from the perichoroidal space and
divide to form the annular plexus also known as
the perilimbal ring
e. by nerves that are specific to pain
14. With respect to the choroid:
a. it extends from the iris anteriorly to the optic nerve
posteriorly
b. it is thickest at the posterior pole and thins as it passes anteriorly
c. it has strong attachments to the sclera in the region where the
vortex veins leave the globe at the equator
d. its pigment cells absorb light penetrating the retinal pigment
epithelium to prevent reflection
e. changes in flow of the vasculature may be responsible for heat
exchange from the retina
15. The choroid:
a. consists of 3 layers, from superficial to deep: vessel,
capillary,
Bruch’s membrane
b. is supplied by the long and short posterior ciliary arteries that
pierce the sclera to form the arterial circle of
Zinn
c. is innervated by the long ciliary nerves that are branches of the
lacrimal nerve of ophthalmic division of trigeminal
nerve.
d. has as its innermost layer Bruch’s membrane that consists of 4
components
e. is bounded externally by a potential space called the
suprachoroidal space