Chapter 2 - Eye

Question 1

Eye - Parts (11)

Answer 1

Retina 
Cornea 
Aqueous humour 
Pupil 
Iris 
Lens
Vitreous humor 
Sclera 
Tapetum 
Optic nerve 
Blind spot

Question 2

Eye - Functions:
Retina
Cornea
Aqueous humour

Answer 2

Retina - the layer of light sensitive cells at the back of the eye. The retina detects images focused by the cornea and the brain lens. The retina is connected to the brain by the optic nerve.

Cornea - a tough, clear covering over the iris and the pupil that helps protect the eye. Light bends as it passes through the cornea. This is the first step in making an image on the retina. The cornea begins bending light to make an image. The lens finishes the job.

Aqueous humour - a clear fluid that helps the cornea keep its rounded shape.

Question 3

Eye - Functions:
Pupil
Iris
Lens

Answer 3

Pupil - the pupil is a dark circle in the centre of your iris. It’s a hole that lets light into the inner eye.

Iris - a muscle that controls how much light enters the eye. It is suspended between the cornea and the lens.

Lens - a clear, flexible structure that makes an image in the eyes retina. The lens is flexible so that it can change shape, focussing on objects that are close up and objects that are far away

Question 4

Eye - Functions
Vitreous humour
Sclera
Tapetum

Answer 4

Vitreous humour - the thick, clear jelly that helps give the eyeball its shape.

Sclera - the thick, tough, white outer covering of the eyeball.

Tapetum - the colourful, shiny material located behind the retina. Found in animals with good night vision. Reflects light back through the retina.

Question 5

Eye - Functions
Optic nerve
Blind spot

Answer 5

Optic nerve - the bundle of nerve fibres that carry information from the retina to the brain

Blind spot - the place where the optic nerve leaves the retina. Each eye has a blind spot where there are no light sensitive cells.

Question 6

Rods and Cones

Answer 6

Cones:

• responsible for vision of detail
• responsible for colour vision
• require high levels of light in order for them to respond
• 6 500 000 in each eye

Rods:

• responsible for vision in low light
• have low vision acuity
• can only register in black and white
• 125 000 000 in each eye