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Description
Flashcards by Liam Musselbrook, updated more than 1 year ago
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Created by Liam Musselbrook
about 8 years ago
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| Question | Answer |
| How is the eye divided into portions? | Anterior: anterior to and including the lens Posterior: posterior to the lens |
| Sclera | Interlacing bundles of collagen fibres Relatively avascular Continuous with cornea at limbus Lamina cribosa - porous hole in sclera for optic nerve |
| What are the layers of the cornea? | 1. Epithelium 2. Bowman's membrane 3. Stroma 4. Desemet's membrane 5. Endothelium |
| How is refractive power divided in the eye? What percentages? | 75% Cornea 25% Lense |
| What are the layers of the tear film? | 1. Oily layer 2. Aqueous layer 3. Mucous layer |
| What are the lacrimal apparatus? | Main lacrimal gland: supertemporal orbit, parasympathetic innervation from greater petrosal nerve (CNVII) Drainage: puncta and canaliculi > lacrimal sac > nasolacrimal duct > inferior meatus |
| Describe the flow of aqueous humour | 1) Secreted into posterior chamber by ciliary body 2) Flows into anterior chamber via pupil 3) Drains into Schlemm's canal via trebecular network |
| What is the role of aqueous humour? | Provides nutrients to avascular cornea and lens Maintains ocular pressure |
| What suspends the lens from the ciliary process? | Zonule fibres |
| Ciliary body | Continuous with choroid posteriorly, attached to iris and scleral spur anteriorly Innervation: Parasympathetic fibres - CNIII Pars plicata: relaxes zonule and controls accomadation (near vision) Pars plana: opens trebucular pores -> drainage of humour into Schlemm c |
| Iris: What is are the innervations for dilator pupillae and sphincter pupillae? | Dilator: Sympathetic fibres of superior cervical ganglion Sphincter: Parasympathetic - CNIII |
| What is the choroid? What does it supply? | Meshwork of blood vessels, with capillaries on internal layer Directly supplies the outer layers of the retina and RPE |
| Retinal Pigment Epithelium (RPE) | Outer layer (single layer) Opaque pigment scatters some light, improving image Role in photopigment regeneration Controls movement of substances from choroid to neuroretina Separated from choroid by Bruch’s membrane |
| Eye opening and closing Which muscles and their innervations? | Opening: orbicularis oculi muscle, facial nerve (CNVII) Closing: levator palpebrae superioris, occulomotor nerve (CNIII) |
| Conjunctiva | From margins of eyelids to limbus Palpebral/Tarsal: lines eyelids Bulbar: covers eyeball (anterior sclera) |
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