Human vision and function/Part 1: How the eye works/1.2 Anatomy of the eye/Answers

1. What is the function of the conjunctiva? To protect the surface of the eye and prevents objects from entering the eye.

2. Where can you find the meibomian glands and what do they do? ''Found on the inner surface of the eyelids. They assist with lubricating the eye by secreting oil into the tear film, this helps to limit evaporation of tears.''

3. What are the names of the 2 main eyelid muscles? Orbicularis Oculi (controlled by Cranial Nerve VII) and Levator palpebrae (controlled by Cranial Nerve III).

4. Where are most of our tears produced? In the lacrimal gland.

5. What are the 3 chambers of the eye? Vitreous chamber, posterior chamber, anterior chamber.

6. What is the function of the ciliary body. ''Pulls on the lens via the zonules which attach to the lens of the eye. This changes the focusing power of the lens.''

7. List the 3 sections of the lens. Capsule, cortex and nucleus.

8. What main things should you look for when examining the retina? Macular, Fovea, optic disk and arteries and veins.

9. What are the light sensitive cells in the retina called? Rods and cones (photoreceptors).

10. Name the 6 extra-ocular muscles ''4 rectus muscles (superior, inferior, lateral and medial), these attach at the Annulus of Zinn. 2 oblique muscles (superior and inferior)''

11. What is the function of the aqueous humour? To provide nutrients to the anterior section of the eye, especially the cornea.

12. Why are the cornea and lens transparent? ''Light needs to enter the eye through the cornea and lens. If these structures are not clear, light will not be able to pass through it to the retina.''

13. Describe the shape and anatomical position of the lens. ''The lens is round but flat. It is found between the anterior and posterior chambers and is held in place by the zonule fibres.''

14. What could happen if the lens is not transparent? Light will not be able to enter the eye and stimulate the rod and cone photoreceptors therefore a person’s vision will be affected.

15. How will the shape of the lens influence refraction of light through the eye and why is the print magnified through the lens?? The lens focuses light in the eye and works as a magnifier.