The Senses

Question 1

Receptors

Answer 1

A cell or group of cells that detects a stimulus e.g. heat and light

Question 2

A Sense Organ

Answer 2

Is an assembly of specialised sensory receptors

Question 3

Conjunctiva

Answer 3

Protects against infection

Question 4

Sclera

Answer 4

Keeps the shape of the eye

Question 5

Cornea

Answer 5

☆ How is it suited to carry out its function? - Curved and Transparent
☆ Function = Bends light towards the retina

Question 6

Choroid

Answer 6

Has blood vessels to nourish the eye

Question 7

Iris

Answer 7

☆ Controls the amount of light entering the eye
☆ How? - Muscular contraction

Question 8

Iris in bright light

Answer 8

Relaxes (gets longer, pupil gets smaller so less light enters the eye)

Question 9

Iris in dim light

Answer 9

Contracts (gets smaller, pupils gets bigger so more light enters the eye)

Question 10

Pupil

Answer 10

Allows light into the back of the eye

Question 11

Lens

Answer 11

☆ Adaptations = Curved, elastic and transparent
☆ Function = To focus light onto the retina

Question 12

Ciliary Muscle

Answer 12

Surrounds the lens and causes the shape of the lens to change when we look at near or far objects. This is a reflex action known as accommodation.

Question 13

Suspensory ligaments

Answer 13

Holds the lens in place

Question 14

Retina

Answer 14

☆ Converts light into nerve impulses
☆ Types = Rods and Cones

Question 15

Rods

Answer 15

☆ Active in dim light
☆ Black and white vision
☆ Found all over retina

Question 16

Cones

Answer 16

☆ Active in bright light
☆ Colour vision
☆ Found mostly at fovea

Question 17

Fovea (Yellow Spot)

Answer 17

Is where most images are focused

Question 18

Blind spot

Answer 18

☆ Where optic nerve leaves the eye
☆ No rods or cones here

Question 19

Optic nerve

Answer 19

Brings impulses from the retina to the brain

Question 20

Aqueous humour

Answer 20

Holds the front of the eye (cornea) in shape

Question 21

Vitreous humour

Answer 21

Gives shape to the eye and supports the lens

Question 22

Why are two eyes better than one?

Answer 22

☆ Increased visual field
☆ 3D vision
☆ Can judge distance of objects

Question 23

Hearing

Answer 23

Detection of vibrations, their frequency and amplitude

Question 24

Balance

Answer 24

Detection of direction of motion, acceleration and head position related to gravity

Question 25

Structure

Answer 25

Composed of three sections;
☆ Outer ear = air
☆ Middle ear = air
☆ Inner ear = lymph

Question 26

Pinna (outer ear)

Answer 26

Collects sound waves

Question 27

Auditory canal

Answer 27

Tube that carries the sound waves to the eardrum

Question 28

Eardrum

Answer 28

Vibrates due to the air vibrations that reach it

Question 29

Ossicles (bones)

Answer 29

Consist of the hammer, anvil and stirrup which transmit vibrations from the outer to the inner ear and amplify the vibrations

Question 30

Estuchian tube

Answer 30

☆ Connects the middle ear to the pharynx
☆ Equalises pressure

Question 31

Cochlea

Answer 31

Contains sound receptors that convert sound waves into nerve impulses

Question 32

Auditory / Cochlear nerve

Answer 32

Carries impulses from the cochlea to the cerebellum of the brain

Question 33

Semi - circular canals

Answer 33

☆ Controls balance
☆ Their are 3 to control balance in three dimensions
☆ Nerve impulse generated for balance

Question 34

Vestibular nerve

Answer 34

Carries impulses from the balance structures to the cerebellum of the brain

Question 35

How do we hear?

Answer 35

☆ Sound is caused by vibrations in the air
☆ Vibrations are collected by the outer ear, pass through the middle ear where they are changed to electrical impulses and sent to the brain which interprets them as sound

Question 36

Glue ear

Answer 36

☆ Cause = Middle ear fills with sticky fluid instead of air, it can be caused by infection or a blocked eustachian tube
☆ Symptoms = Reduced hearing
☆ Treatment = Nose drops or grommets

Question 37

Grommets

Answer 37

Tiny ventilation tubes inserted into the ear, they allow air in, which builds up and forces the fluid down the eustachian tube, the tubes fall out naturally

Question 38

External muscle

Answer 38

Pulls on the eye causing it to change direction