Week 10 Flashcards
what is the function of the crystalline lens
transparency/refraction
accommodation
what is the shape of the lens
biconvex - anterior less convex
between iris and vitreous
what is the lens supported by
suspensory ligaments from ciliary processes
What is the capsule
transparent and highly elastic basement membrane
moulds lens into shape during accommodation
what is the lens epithelium
Single layer of cuboidal epithelial cells, under the anterior capsule
Become more columnar towards the equator
Produces lens fibres; transports nutrients from aqueous humour to lens interior
what are the lens fibres
each fibre is a long hexagonal prism
New fibres are laid over the older ones
Fibre nuclei form a lens bow
Newer cells form the cortex
As the lens grows and fibres become more packed
the lens becomes sclerotic, with a progressive loss of accommodation with age
what is in the pars plicata
ciliary body
what are the zonular fibres
suspensory ligaments
what is a cortical cataract
opacification in discrete pathces within the cortex
what are the functions of vitreous humour
supports the prosterior surface of the lens and lines retina
transmits light
what is the composition of the vitreous humour
collogen filaments
hyaluronic acid
what is the choroid
provides blood
pigmented absorb stray light
heat exhange from the retina
suprachoroid
Transition between the choroid and sclera
Consists of collagen fibres, melanocytes and fibroblasts
Allows a passage for nerves and blood vessels to anterior uvea
what is the two layers of the stroma of the choroid
haller’s layer - large vessels/near sclera
sattler’s layer - smaller vessels/near retina
what is choriocapillaris
Single layer of wide-bore capillaries
Packed tightly in a single plane against the basal lamina
Nourish the outer part of the retina
