bio 07 ce一題問題..20分

我答因為fall off of retina leads choroid expose.
choroid absorb light thus cause blindness
但個老師唔比分
佢marking scheme寫.
fall off of retina -->cannot take nutrient from choroid

撇開有冇nutrient supply 唔計, 不論retina 有冇fall off, choroid 都係會absorb light, retina 都可以absorb light 用來form image, 而choroid都一樣可以防反射, 唔會致盲. 一定要另找原因.
所以你個個唔可能係正確答案.

2007-08-29 23:42:23 補充：
個問題係你眼入面, 邊樣係前, 邊樣係後?? 唔記得就來這have a quick look:http://en.wikipedia.org/wiki/Image:Schematic_diagram_of_the_human_eye_en.svg光線入眼應該先到retina, 剩餘的再到choroid.

2007-08-29 23:43:57 補充：
所以決定有冇光到retina, 係佢前面既野, 例如lens, aqueous humor, vitreus humor. 呢d地方吸光既話, 就係白內障之類眼盲既因素.就唔係retina後面既野, 例如choroid, sclera, optic nerve 吸唔吸光, 因為光一定先到retina,再到個幾樣structure.

2007-08-29 23:48:58 補充：
choroid 吸光, 所以避免retina吸剩既光 係眼球入面周圍亂咁反射. 既係choroid吸光係正常, 所以眼球入面保持黑暗. choroid 唔吸光先至係係唔正常, 像sclera一樣係白色既話, 眼入面就太光亮, 造成散射, 白茫茫咩image都睇唔清.

2007-08-29 23:57:34 補充：
所以, 原本你提問: fall off of retina leads choroid expose 係事實, 但係: choroid absorb light thus cause blindness 就錯晒.因為choroid absorb light係正常狀況, 不會致盲.

2007-08-29 23:57:50 補充：
而像你補充入面咁講, retina真係fall off曬得番choroid expose,, chorid咪absorb all light,, no image will be formed 就係因果掉轉. 因為retina不在正常位置, 所以冇野攔截d光, 所有光都到choroid. 咁retina已經唔係image既位置, 已經吸唔到光,出唔到signal, 已經係盲左, choroid吸到所有光只係[結果] 唔係[原因]. 就更加唔成立啦.

But according to my opinion
I would say because of the falling off of the retina
where there are those sensory cell (rod and cone),
the light ray entered the inner chamber of the eye
would not be received by the rod and cone
-> so that no nerve impulses can be generated to send off to the brain
其實我覺得無可能唔答呢 part
不過　HKEAA 既　ans 出名怪怪的