The Senses

Question 1

Conjunctiva

Answer 1

Transparent outer layer

Protects sclera

Question 2

Sclera

Answer 2

White of the eye
Opaque and tough
Holds eye in shape

Question 3

Cornea

Answer 3

Transparent part of sclera

Lets light in and bends it towards the retina

Question 4

Choroid

Answer 4

Dark coloured layer
Contains melanin to absorb light and blood vessels to nourish eye
Ensures no internal reflection

Question 5

Retina

Answer 5

Where the light receptors are located

Question 6

Function of rods

Answer 6

Detect b and w
Work in dim light
Most common

Question 7

Function of cones

Answer 7

Detect colours
Work in bright light
Least common, found mostly at fovea

Question 8

Fovea

Answer 8

Only contains cones

Focuses images

Question 9

Blind spot

Answer 9

Where the nerves and fibres leave the eye

Not sensitive to light due to lack of cones and rods

Question 10

Optic nerve

Answer 10

Carry impulses from rods and cones to the cerebrum of the brain

Question 11

Pinna

Answer 11

Cartilage

Channels vibrations into auditory canal

Question 12

Auditory canal

Answer 12

Carries vibrations to eardrum

Wax secreted to trap dust and protect inner ear

Question 13

Eardrum

Answer 13

Separates outer and middle ear

Vibrates

Question 14

Ossicles

Answer 14

Hammer anvil and stirrup
Smallest bones
Transmit and amplify vibrations

Question 15

Eustachian tube

Answer 15

Runs to throat

Equalises pressure on either side of eardrum

Question 16

Cochlea

Answer 16

Converts pressure waves to electrical impulses

Question 17

Describe in four steps how the cochlea works

Answer 17

1. Vibrations from stirrup arrive at cochlea
2. Pass through oval window and form pressure waves in the lymph in the cochlea
3. These waves stimulate receptors in cochlea which are attached to sensory cells called Organ of Corti
4. Cause electrical impulses to go to the brain

Question 18

What controls balance

Answer 18

The three semicircular canals - vestibular apparatus

Question 19

Hearing disorder

Answer 19

Glue ear

Question 20

Cause of hearing disorder

Answer 20

Surplus sticky fluid in middle ear, possibly due to infection
Prevents movement of eardrum and ossicles

Question 21

Correction for hearing disorder and how it works

Answer 21

Grommets inserted into ear

Allow air in and force fluid down the Eustachian tube