Brain and eye

Question 1

Parts of the brain

Answer 1

The cerebral cortex
The medulla
The cerebellum

Question 2

Cerebellum

Answer 2

controls muscle contraction and balance
Circular part at the back

Question 3

Medulla

Answer 3

controls unconscious activity
Dangly bit

Question 4

Cerebral cortex

Answer 4

controls consciousness, memory, intelligence and language
Main part at the top of the brain

Question 5

How has the brain been studied

Answer 5

neuroscientists have mapped regions of the brain to their functions by studying patients with brain damage, electrically stimulating parts of the brain and my using MRI scanning, but the brain is hard to study and treat due to its complexity and delicacy.

Question 6

What is the brain

Answer 6

The brain controls all complex behaviour, and it contains billions of connected neurones.

Question 7

Focus on near object

Answer 7

• the ciliary muscles contract
• the suspensory ligaments loosen
• the lens is then thicker and refracts light rays strongly.
• Light rays refracted onto retina

Question 8

Focus on far object

Answer 8

• the ciliary muscles relax
• the suspensory ligaments are pulled tight
• the lens is then pulled thin and only slightly refracts light rays.
• Light rays refracted onto retina

Question 9

Long-Sightedness

Answer 9

(hyperopia), in which light rays focus behind the retina
corrected using glasses with convex () lenses

Question 10

Short-Sightedness

Answer 10

(Mypoia), in which light rays focus in front of the retina
Corrected using glasses with concave )( lenses

Question 11

Treatments for eye-defects

Answer 11

soft and hard contact lenses, laser eye surgery (which changes the shape of the cornea) and replacement lens surgery (which involves inserting an artificial lens).

Question 12

Bright light

Answer 12

In bright light, circular muscles in the iris contract, and radial muscles relax. This makes the pupil smaller (constricts), reducing the amount of light entering the eye and protecting the retina from damage.

Question 13

Dim light

Answer 13

In dim light, radial muscles in the iris contract, and circular muscles relax. This makes the pupil larger (dilates), allowing more light to enter so that vision improves in low-light conditions.

Question 14

Optic nerve function

Answer 14

Light entering the eye is focused onto the retina, where it is detected by light-sensitive receptor cells (rods and cones). These cells convert the light into electrical signals.

The optic nerve then transmits these signals to the visual cortex in the brain, where they are interpreted as images, allowing us to see.