Opt 114 characteristics: vitreous (composition)

how many components are there of the vitreous

5

what are the components of the vitreous

water, collagen, glycosaminoglycans/proteoglycans, cells, electrolytes/ions/organic substances

what is the vitreous mostly composed of

water

exactly how much of the vitreous is water

99%

why is the vitreous difficult to study

the large contribution of water means that fixating the tissue is hard (gets dehydrated) because it introduces artifacts

what collagen is found in the vitreous

type 2, 9, 5, 11

what is the main collagen in the vitreous

type 2

what does type 9 collagen do in the vitreous

link type 2 together

where are type 5, 11 collagen doing in the vitreous

integrated wtih type 2

where is teh most collagen in the vitreous

vitreous base

where is the least collagen in the vitreous

central vitreous

from order of highest density of collagen to lowest, rank the locations in the vitreous

vitreous base > posteiror cortex > anterior cortex> central vitreous

what are the collagen fibers separated by in the vitreous

GAG chains

if collagen in the vitreous is damaged, does it regenerate

nope

what are glycosaminoglycans

repeating disaccharide units of amino sugar, uronic acid, or galactose without branching

function of hyaluronic acid in the vitreous

fills space between collagen, maintains transparency of the vitreous maintaining spacing between collagen fibrils

what creates the gel structure of the viterous

hyaluronic acid

what is the other GAG in abundance in the vitreous

chondroitin sulfate

which GAG is the most abundant in the vitreous

hyaluronic acid

which GAG is a proteoglycan (linked to a core protein)

chondroitan sulfate

what cells are present in the vitreous

hyalocytes, fibroblasts

what are the percentages of hyalocytes and fibroblasts in the vitreous

90% hyalocytes, 10% fibroblsts

Hyalocytes are more numerous in adult or infancy

fetal vitreous

what is the function of hyalocytes in fetal vitreous

help regress the hyaloid artery

what is the function of hyalocytes in adult vitreous

unclear, may syntehsize hyaluronic acid/glycoprotein for collagen, or have phagocytic properties

where are fibroblasts found in the vitreous

near vitreous base and optic disc

what electrolytes/ions are in the vitreous

Na, K, Ca, Mg, Cl, PO4

what organic susbtances are found in the vitreous

ascorbate, glucose, lactate

What is the function of ascorbate in the vitreous

antioxidant, protects the retina from free radical damage

the concentrations of ions/organic susbtances are (the same/different) from blood

substantially different