Collagen And The Eye Flashcards
4 types of embryonic CT
Mesenchymal
Mucous
Supporting
Hematopoietic Tissue (blood and bone marrow)
What is a fixed cell? Ex?
Cells that are made and reside in the same tissue.
Fibroblasts, they’re made and reside in the CT
What is a wandering cell? Ex?
Cells that are not fixed to their tissue and they travel.
Eosinophils, mast cells, and plasma cells (derived from B-lymphocytes)
What do fibroblasts produce?
Procollagen
Found in connective tissue and are flexible/have a high tensile strength
Collagen fibers
Collagen structure
Procollagen single strands combine to make a triple helix (collagen fibril), then collagen fibrils combine to make a collagen fiber
Its tensile strength is greater than steel!
How many types of collagen are recognized in humans?
16
Which type of collagen makes up 90% of collagen in the body?
Type 1
3 catergoes of collagen
Fibrous
Non-fibrous
Filamentous
Collagen that is seen in an electron microscope as thick fibers
Ranges from 200 nm in skin/tendon to 25 nm in cornea
Fibrous collagen
Range of fiber size in the cornea
25-30 nm
Uniform
Variable fiber size in the skin
20 to 200 nm
Groups of collagen in the skin/cornea
Genetic types I, II, III collagens
Collagen that forms the thin basement membranes separating the fibrous stromatolites tissue from the cells
Non-fibrous collagen
Size and location of non-fibrous collagen
25 nm in capillaries and golmeruli
200 nm in the lens
What is the only catergory of collagen to be found in non-fibrous collagen?
Type IV collagen
IN ALL BASEMENT MEMBRANES
Collagens that form loosely aggregates fibers with little of no periodicity
Filamentous collagen
Filamentous collagen can be subdivided into what? And what types are included?
Pericellular and matrix collagen
Types VI, VII, IX, and X
Collagens of the Cornea
Transparent tissue containing fine collagen fibers of UNIFORM diameter with a high degree of spatial organization
Collagens of the Sclera
Opaque tissue containing thick interwoven collagen fibers
Structural, strength and resilience due to interlacing collagen fibers
30 nm - 300 nm
Mainly type 1 and some type III
Collagen of the Vitreous body
Polysaccharide gel containing small amounts of fine collagen fibers
7-13 nm
Embedded in a hyaluronate gel
Function to stabilize shape of gel and reduce compressibility
Mainly type II collagen
Collagen of the retina
Typical thin basement membrane
Non-fibrous
Bruch’s membrane
Type IV
Collagen of the choroid
Highly vascularized tissue of the iris…?
The human cornea contains __% collagen
90
Vitreous body contains both:
Collagen fibers and elastic fibers
For maintenance of a) intraocular pressure and b) acting as a shock absorber
What type of collagen is in the lens capsule?
Type IV
non-fibrous
Membrane located under the corneal stroma, that separated the corneal stroma from the corneal epithelium
Consists of what 2 types?
Descemet’s membrane
90% type IV and 10% type V
Type VI collagen is found where
Extra cellular matrix of the cornea
Throughout the corneal stroma
Where is type VIII found?
Descemet’s membrane
Synthesized by the corneal endothelial cells
The vitreous body contains a lot of what type?
Type IX
Filamentous, but has same cross-linking as fibrous
When the cornea bulges, due to problems with the collagen
Keratoconus
Collagen is important in the cornea because..
It plays an important role in the transparency
The corneal strength relies on:
The head-to-tail orientation
Cross linking
More linking, stronger the tissue
When the need to strengthen the cornea arises, what procedure is done?
Corneal Cross Linking
