Parts of the Eye

Question 1

Conjunctiva

Answer 1

Mucus membrane, covering sclera
Secretes mucus to keep the front of the eyeball moist.

Question 2

Cornea

Answer 2

Dome-shaped, flexible and transparent-layer that is able to reflect light rays into the eye (refracts light the most)

Question 3

Sclera

Answer 3

Tough, white outer covering of the eyeball continuous with the cornea
Eye muscles (rectus muscles) attached to this layer facilitates the movement of eyeball (contracts and shorten, pulling the eyeball).

Question 4

Aqueous Chamber

Answer 4

Filled with aqueous humor, a transparent, watery fluid
Aqueous humor keeps the front of the eyeball firm and refracts light into the pupil.
Space between the lens and cornea

Question 5

Lens

Answer 5

Transparent, circular and biconvex structure
Shape or thickness can be changed in order to refract light onto retina

Question 6

Suspensory Ligament

Answer 6

Attaches the edge of the lens to the ciliary body
It is not muscles and cannot relax or contract

Question 7

Vitreous Chamber

Answer 7

Filled with vitreous humor, a transparent jelly-like substance
Vitreous humor keeps the eyeball firm and refracts light onto the retina

Question 8

Retina

Answer 8

Contains light-sensitive cells known as the photoreceptors which consists of ‘rods’ and ‘cones’. (photoreceptor cells convert light to nerve impulse)
Connected to nerve fibres from optic nerves.

Question 9

Fovea

Answer 9

A small yellow depression where images are focused and is where the sharpest image is seen
Enables a person to have detailed colour vision

Question 10

Blind spot

Answer 10

Region where the optic nerves leave the eye
Does not contain any photoreceptors, therefore not sensitive to light.

Question 11

Choroid

Answer 11

Black pigmented layer which prevents the internal reflection of light
contains blood vessels that carry oxygen and nutrient to eyeball and remove metabolic waste products from the eyeball.

Question 12

Optic Nerve

Answer 12

Transmits impulses to the brain when photoreceptors are stimulated

Question 13

Iris

Answer 13

A sheet of muscles consisting of involuntary muscles - radial, circular muscles
Contains a pigment which gives its eye its colour.

Question 14

Pupil

Answer 14

A hole in the center of the iris, allowing light to enter its eye

Question 15

Eyelids

Answer 15

Protects the cornea from mechanical damage
Close/ squint to prevent excessive entry of light
Blinking spread tears over the eyes so that dust can be wiped off

Question 16

Tear Gland

Answer 16

Secretes tears to:
Wash away dust particles
Lubricate the conjunctiva, reducing friction when the eyelid moves

Question 17

Eyelash

Answer 17

Shields the eye from dust particles

Question 18

Pupil Reflex

Answer 18

A reflex that controls the diameter of the pupil, in response to the intensity of light. Hence controlling the amount of light enetring the eye.

Question 19

What parts of eye are involved?

Answer 19

Retina
Iris (circular and radial muscles)
Size of pupil