Parts Of The Eye

Question 1

Conjunctiva

Answer 1

• Thin transparent membrane covering the cornea

* Protects the cornea from damage

Question 2

Sclera

Answer 2

• Tough opaque connective tissue covering the eye - replaces by transparent cornea at the front
• Protects against damage; site of attachment of eye muscles

Question 3

Cornea

Answer 3

• Front transparent part of the sclera

* Transparent and most refraction of light occurs here

Question 4

Aqueous honour

Answer 4

• Transparent watery fluid between cornea and lens

* Maintains the shape of the front part of the eye

Question 5

Iris

Answer 5

• Muscular later with both circular and radial muscle; contains pigments that absorb light
• Adjusts the size of the pupil to control the amount of light entering the eye

Question 6

Pupil

Answer 6

• Gap within the iris

* The area through which light reaches the lens and enters the centre of the eye

Question 7

Ciliary body

Answer 7

• Contains a muscular ring of ciliary muscle around the eye - suspensory ligaments extended from the ciliary body hold the lens in place
• Adjusts the shape of the lens to focus light rays

Question 8

Suspensory ligaments

Answer 8

• Ligaments that connect the ciliary body to the lens

* Transfers tension in the way of the eyeball to make the lens thinner - important when focusing on distant objects

Question 9

Lens

Answer 9

• Transparent biconcave structure with refractory properties
• Refracts light and focuses light rays in the retina

Question 10

Vitreous humour

Answer 10

• Transparent jelly-like material between the lens and back of the eye
• Maintains the shape of the rear part of the eye and supports the lens

Question 11

Retina

Answer 11

• Inner layer of the eyeball containing the light sensitive receptor cells (rods and cones)
• When stimulates the rods and cones initiate impulses in the associated neurones

Question 12

Fovea

Answer 12

• Region in the centre of the retina that is particularly rich in cones but does not contain rods
• Part of the eye that gives the clearest daylight vision

Question 13

Choroid

Answer 13

• A layer of pigmented cells between the retina and sclera

* Contains blood vessels that supply the retina; prevents reflection of light back through the eye

Question 14

Optic nerve

Answer 14

• A bundle of sensory nerve fibres that leave the retina

* Transmits impulses from the retina to the brain

Question 15

Blind spot

Answer 15

• Part of the retina where the sensory neurones that unite to form the optic nerve leaves the eye
• Contains no light sensitive cells (rods and cones) therefore is not sensitive to light