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23 Cards in this Set
- Front
- Back
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Basic iris colour is determined?
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Genetically
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How many main factors are responsible for the colour of the iris?
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3
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What are the 3 colours of the iris?
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1. Pigment granules in the iris pigment epithelium.
2. The concentration of the pigment within the iris stromal melanocytes 3. The light scattering and absorptive property of the extracellular components of the iris stome. |
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The iris pigment consists prmarily of?
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Menanin
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What are Kreiges 2 classifications of pigments
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Exogenous (external)
Endogenous (internal) |
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Exogenous (external) pigment deposit classification refers to?
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Chemical compounds & heavy metals
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Endogenous (internal) pigment deposit classification refers to?
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Haemoglobin/ferrritin/haemosiderin
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Autogenous
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Tyrosin/melanin & fats/lipofuscin
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Melanin formation is controlled by the?
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Anterior pituitary gland
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Melanin deposits on the iris indicate
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serious metabolic disturbance
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Red to Dark Brown is known as?
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Haemosiderin/haemofuscin
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Haemosiderin contains which pigment
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Iron
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Haemosiderin or iron pigment indicates?
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destruction of large quantities of red blood cells
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The colour yellow to dark brown is
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Lipofuscin
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Lipofuscin is also known as?
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Wear & Tear pigment
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Lipofuscin represents plague in?
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Grey matter & oxidation of fat
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Lipofuscin is also a degeneration product in young people as a sign of exhaustion of
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liver/renal/pancreas
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What are the 3 pigment cells
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1) Stromal Melanocytes
2) Iris pigment epithelium 3) Clump cells |
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Stromal melanocytes are derived from?
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Neural crest
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Iris pigment epthelium is derived from
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Neuroectoderm of the optic cup
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Clump cells are derived from
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Pigment epithelial & histiocytic origin
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New born babies hav what colour eyes?
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Blue
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Albinos have what pigment in thier eyes?
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None
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