Vitreous Flashcards
The vitreous body makes up approximately ____ of the volume of the eye and thus is the ______ single structure of the eye.
a. 10%, smallest
b. 90 %, largest
c. 80%, smallest
d. 80%, largest
e. 90%, smallest
d. 80%, largest
The length of the vitreous body in the newborn eye is approximately _______mm and by the age of 13 years, the actual length of the vitreous increases to ____mm
a. 16.1 mm, 10.5mm
b. 12.1 mm, 15,1mm
c. 10.1 mm, 16.1 mm
d. 10.5 mm, 16.1 mm
d. 10.5 mm, 16.1 mm
The mean adult vitreous is ____ mm.
a. 12.5 mm
b. 14.5 mm
c. 16.5 mm
d. 18.5 mm
c. 16.5 mm
The vitreous is actually ~_____ water.
a. 75%
b. 80%
c. 90%
d. 98%
d. 98%
The major non-aqueous biochemical components: fibrinogen/collagen and Glucosamine/Glycosaminoglycans (GAGs) form the vitreous into a gel that has important viscoelastic/ viscoplastic properties.
collagen, Glycosaminoglycans (GAGs), viscoelastic
The gel content increases/decreases with age.
decreases
T/F In the human, liquefaction is already at 20% (volume) by around age 18 and progresses to greater than 50% by the 80th decade.
True
T/F The existence of a gel in the vitreous does not depend on interactions between GAGs and collagen.
False, does depend
Type ____ collagen accounts for ____ of the total vitreal collagen and is the principal “structural” collagen present.
a. III, 75%
b. I, 50%
c. II, 75%
d. II, 50%
c. II, 75%
T/F Type II collagen is essential to gel formation in the vitreous.
True
Combined types V/XI collagen represent ~____ of the collagen present.
a. 10%
b. 20%
c. 30%
d. 40%
a. 10%
T/F A difficulty with investigating the vitreous body is that any attempts to define vitreous morphology are in fact attempts to visualize a tissue, which by design is intended to be visible.
False, invisible
T/F A difficulty with investigating the vitreous body is the various techniques that have previously been used to define the structure of the vitreous body are combined with artifacts that make interpretations difficult in terms of the true in vivo physiologic situation.
True
In the late/early stages of embryology, the optic cup is mainly occupied by the retina/lens vesicle.
As the optic cup grows, the space formed is filled by a system of bony/fibrillar material, presumable secreted by the cells of the embryonic retina/cornea.
early, lens, fibrillar, retina
T/F The penetration of the hyaloid artery, more fibrillar material, and other vessels all contributes to filling the space, known as the primary vitreous.
True
The size of the vitreous cavity increases and the hyaloid vascular system regresses developing the primary/secondary/tertiary vitreous.
secondary
T/F The main hyaloid artery remains for some time, but it eventually disappears and leaves in its place a tube of primary vitreous surrounded by the secondary vitreous, running from the retrolental space to the optic nerve. The tube is called Cloquet’s canal.
True
The Cloquet’s canal: a tube of primary/secondary vitreous surrounded by secondary/tertiary vitreous running from the retrolental space to the optic nerve.
primary, secondary
T/F The vitreous is the suspensor fibrils that suspend the lens, are developed from the fibrillary material.
False, Zonules
Zonules of the lens are termed the primary/secondary/tertiary vitreous.
tertiary
The mature vitreous body is a opaque/transparent gel and is spherical except at anterior/posterior end which is concave/convex .
transparent, anterior, concave
The innermost/outermost part of the vitreous, called the cortex, is divided into an anterior cortex and a posterior cortex, the latter being approximately 100/200 µm thick.
outermost, 100
The vitreous base is a two/three-dimensional zone
three
The vitreous base extends approximately from ___mm anterior to the ora serrata to ___mm posterior to the ora serrata, and it is several mm thick.
a. 3, 2
b. 2, 2
c. 2, 3
d. 3, 3
c. 2, 3
The collagen fibrils are especially densely packed in this region
The vitreoretinal interface is the _inner/outer part of the cortex, which includes the internal limiting membrane (ILM) of the cornea/retina and anchoring fibrils of the conjunctiva/vitreous body.
outer, retina, vitreous
The ILM is a retinal structure between ___ and ___ µm thick, consisting mainly of type ___ collagen and proteoglycans. It contains several layers and can be considered the basal lamina of the ____ cells.
a. 1, 2, IV, Tarsal
b. 1, 3, IV, Mueller
c. 2, 3, III, Mueller
d. 1, 2, III, Tarsal
b. 1, 3, IV, Mueller
The vitreous cortex is firmly attached to the ILM at:
a. the vitreous base
b. Around the optic disc (Weiss ring)
c. the vessels
d. In the area surrounding the foveola at diameter of 500 µm
e. none of the above
f. all of the above except e
f. all of the above except e
a. the vitreous base
b. Around the optic disc (Weiss ring)
c. the vessels
d. In the area surrounding the foveola
Clinically important information; you must know!
T/F The aging process of the vitreoretinal interface has been studied with HVF in 209 healthy subjects.
False, OCT not HVF
In the OCT studies, preretinal strands, presumably posterior cortex, were found in _50% / 60% / 70% _of these nonsymptomatic cases with/without biomicroscopic evidence of posterior vitreous detachment (PVD).
60%, without
Blood vs Vitreous
Blood Conc. Vitreous Conc
Ascorbate 1.3 mg/100ml 7.6 mg/100ml
Bicarbonate 27 mmol/liter 25 mmol/liter
GAGs none 25 mg/100ml
Protein 7.3 mg/100ml 55 mg/100ml
Sodium 150 mmol/liter 137 mmol/liter
Potassium 105 mmol/liter 3.8 mmol/liter
Glucose 98 mg/100ml 50mg/100 ml
Vitreous lecture Slide 16
Blood Vs Vitreous Comparison
