Vision

Question 1

Conjuctiva

Answer 1

Transparent membrane the seals the eye from bacteria

Question 2

Lacrimal glands

Answer 2

Produce tears which lubricate the eye and kill bacteria

Question 3

Sclera

Answer 3

Outermost layer that is attached to muscles that move the eyeball

Question 4

Cornea

Answer 4

Transparent window which allows light to enter the eye and causes its refraction

Question 5

Choroid

Answer 5

Middle layer of the eye that consists of many capillaries and pigments that absorb stray light rays to prevent reflection

Question 6

Iris

Answer 6

Coloured part of the eye that has radial and circular smooth muscles that control the amount of light that enters the eye

Question 7

Pupil

Answer 7

Opening in the centre of the iris through which light passes

Question 8

Eye reflex in bright light

Answer 8

Contraction of circular muscles and relaxing of radial muscles, causes the constriction of the pupil so less light is let in. (parasympathetic nervous system)

Question 9

Eye reflex in dim light

Answer 9

Contraction of the radial muscles and relaxing of the circular muscles, causes the dilation of the pupil so more light is let in. (sympathetic nervous system)

Question 10

Ciliary body

Answer 10

Contains the ciliary muscles, which are attached to the lens of the eye by suspensory ligaments. These muscles are responsible for changing the shape of the lens to see far away and close up.

Question 11

Retina

Answer 11

Innermost layer that contains the photoreceptors (rods and cones)

Question 12

Fovea Centralis

Answer 12

Small depression within the retina where cones are concentration, therefore it is the site of the eye’s sharpest vision

Question 13

Aqueous Humour

Answer 13

Transparent liquid in front of the lens. The fluid contains oxygen, glucose, and proteins.

Question 14

Vitreous Humour

Answer 14

Jelly-like fluid located behind the lens. It maintains eye shape, provides nourishment, and helps focus light onto the retina

Question 15

Rods

Answer 15

Photoreceptors that are spread throughout the retina except at the fovea. They respond to low levels of light and help establish the shapes/outlines of objects in our vision.

Question 16

Rhodopsin

Answer 16

Light sensitive pigment that is made up of opsin and retinal. When it absorbs light, it breaks down and the opsin initiates an action potential, which sense impulses to the brain.

Question 17

Cones

Answer 17

Concentrated at the centre of the retina and clumped at the fovea. They respond to colour and are sensitive to either blue, green, or red light.

Question 18

Blind spot

Answer 18

Location of optic nerve, so there are no rods or cones present

Question 19

Optic chiasma

Answer 19

Location where the optic nerves merge. Left side of the field of view is seen by the right side of the brain and the right side of the field of view is seen by the left side of the brain.

Question 20

Accommodation for close up objects

Answer 20

Thick lens, so the ciliary muscles are contracted and the suspensory ligaments are relaxed

Question 21

Accommodation for far away objects

Answer 21

Thin lens, so the ciliary muscles are relaxed and the suspensory ligaments are contracted

Question 22

Light adaptation

Answer 22

Darkness to light shifts light reception from rods to come and from light to dark shifts light reception from the cones to rods

Question 23

Myopia

Answer 23

Nearsightedness, an elongation of the eyeball causes images to fall infront of the retina

Question 24

Hyperopia

Answer 24

Farsightedness, eyeball is too short so close up images fall behind the lens

Question 25

Astigmatism

Answer 25

irregular curvature of the cornea or lens prevents light from focusing properly

Question 26

Cataracts

Answer 26

Clouding of the lens