The Eye

Question 1

Sclera

Answer 1

External layer of the eye that is white, tough, and fibrous. It protects and supports the eyeball.

Question 2

Cornea

Answer 2

Transparent part of the sclera at the front of the eye that bends light rays into the eye.

Question 3

Choroid

Answer 3

Absorbs scattered light not detected by photoreceptors and contains blood vessels

Question 4

Iris

Answer 4

Regulates amount of light that enters the eye. Adjusts size of pupil- adaptation

Question 5

Pupil

Answer 5

the opening for light to enter the inner eye

Question 6

Retina

Answer 6

Thin layer that contains photoreceptors- rods and cones

Question 7

Rods

Answer 7

Photoreceptors sensitive to light intensity

Question 8

Cones

Answer 8

Photoreceptors sensitive to different wavelengths of light (colour vision)

Question 9

Optic Nerve

Answer 9

Transmits sensory information back to the brain

Question 10

Aqueous Humour

Answer 10

A clear, watery fluid in the anterior chamber that maintains the shape of the cornea and provides oxygen and nutrients to surrounding cells

Question 11

Vitreous Humour

Answer 11

A clear, jelly-like fluid in the posterior chamber that helps maintain the shape of the eyeball, and supports surrounding cells

Question 12

Ciliary Muscle

Answer 12

Changes shape of lens in order to focus

Question 13

Fovea Centralis

Answer 13

Contains a high density of cones and provides acute vision

Question 14

Lens

Answer 14

Focuses light rays on the fovea centralis

Question 15

Glaucoma

Answer 15

Happens when the ducts that drain the aqueous humour become plugged. This can lead to pressure building up in the eye and rupturing the blood vessels. Due to lack of oxygen and nutrients, the cells of the eye then deteriorate.

Question 16

Cataracts

Answer 16

As the lens ages, protein structures degenerate making it opaque and light cannot pass through. The condition can cause grey-white spots. Lens can sometimes be surgically replaced

Question 17

Astigmatism

Answer 17

An uneven curvature of part of the cornea. Since the cornea is asymmetrical it cannot bend light rays to meet at the correct focal point, vision is blurred.

Question 18

Hyperopia

Answer 18

Farsightedness. Cannot focus on objects nearby because the eyeball is too short. The light rays do not meet before reaching the retina so the image is focused behind the retina. Convex lenses can correct this by bending light rays at a sharper angle.

Question 19

Colour Blindness

Answer 19

An inherited condition that results in nonfunctional or deficient cone function; inability to see certain colours such as red, green, or blue

Question 20

Myopia

Answer 20

Nearsightedness. Cannot focus on objects far away because eyeball is elongated. Focus of light falls in front of the retina. Concave lenses can correct this by diverging light rays so the image lands on the retina.

Question 21

Blindspot

Answer 21

The area where sensory fibres come together to form the optic nerve at the back of the eyeball. It is deficient in rods and cones.

Question 22

Tapetum

Answer 22

A layer in the choroid that increases absorption of light to stimulate photoreceptors in dim conditions. Reflective - cat eyes seem to glow.

Question 23

Ganglion cells

Answer 23

Special sensory neurons that communicate with bipolar cells in the retina to transmit a nerve impulse to the brain. These cells have long axons that converge at the back of the eye to form the optic nerve.

Question 24

Iodopsin

Answer 24

The general name for any of the three visual pigments found in cone cells that is stimulated by light to initiate a nerve impulse

Question 25

Rhodopsin

Answer 25

A visual pigment found in rod cells that is decomposed by light into retinal and opsin. This change initiates a nerve impulse

Question 26

Opsin

Answer 26

A protein that is the result of the decomposition of rhodopsin

Question 27

Retinal

Answer 27

A derivative of vitamin A (retinol) that is the result of the decomposition of rhodopsin and is instrumental in initiating a nerve impulse.

Question 28

Depth perception

Answer 28

The ability to see in 3 dimensions

Question 29

Adaptation

Answer 29

The process by which the iris adjusts the diameter of the pupil based on light conditions, thus controlling the amount of light that enters the eye and strikes the retina