The senses - sight - functions & structures of eye - ch 13

Question 1

what is the primary function of the eye?

Answer 1

to capture light rays

Question 2

What are the light rays modified into?

Answer 2

nerve impules

Question 3

Where are the nerve impules transferred to?

Answer 3

the visual cortex of the brain

Question 4

What is the role of the visual cortex of the brain once it receives the nerve impulses?

Answer 4

to translate and interpret into images to enable a person to see.

Question 5

Name the functions of the eye?

Answer 5

1. light perception
2. focusing of the light onto the retina
3. refraction
4. light accommodation
5. transmissions of messages to the brain
6. production of tears

Question 6

Name the first part of the eye that light first passes through?

Answer 6

cornea

Question 7

Describe the cornea?

Answer 7

curved clear outer portion of the eye

Question 8

What is the role of the cornea?

Answer 8

It focuses light through the pupil, a round hole located in the centre of the iris.

Question 9

Once the cornea has focused light through the pupil through the centre of the iris, what is the iris responsible for?

Answer 9

the iris controls the diameter and size of the pupil and therefore regulates the amount of light that can reach the retina.

Question 10

Do muscles attached to the iris expand or contract the pupil depending on how much light is present.

Answer 10

Yes, the larger the pupil the more light enters

Question 11

Describe what happens when light passes through the lens?

Answer 11

Muscles in the eye cause the shape of the lens to become thicker or thinner to focus light on the fovea centralis which is in the middle of the macula on the retina at the back of the eye.

Question 12

Describe the process of refraction?

Answer 12

As light passes through the lens, muscles in the eye cause the shape of the lens to become thicker or thinner to focus the light on the fovea centralis, which is in the middle of the macula on the retina at the back of the eye.

Question 13

What does the retina convert the light into?

Answer 13

electric signal.

Question 14

What is the process of the electric signals that has had light received by the retina?

Answer 14

electric signals travel via the optic nerve to the brain stem and then to the visual cortex in the occipital lobe, where it is translated into an image.

Question 15

What is the orbit?

Answer 15

The orbit is the eye socket

Question 16

Where in the body do you find the orbit?

Answer 16

in a space adjoined by the bone of the cheek, the forehead, the temporal bone and the side of the nose.

Question 17

What is the role of fat pads found within the orbit?

Answer 17

to protect the eye

Question 18

What is the name of the gland found in the orbit?

Answer 18

lacrimal gland

Question 19

Where do you find the lacrimal gland?

Answer 19

under the outer portion of the upper eyelid

Question 20

What is the role of the lacrimal gland?

Answer 20

to produce tears to lubricate and moisten the eye and help clear the eye of any foreign matter, such as dust.

Question 21

What is the name of the duct that tears are drained away from?

Answer 21

nasolacrimal duct found in the inner corner of the eye

Question 22

Describe an eyelid?

Answer 22

a thin fold of skin that covers the eye

Question 23

What is the role of the eyelid?

Answer 23

to protect the eye from foreign bodies and bright light

Question 24

How does the eyelid protect the eye?

Answer 24

By keeping the eye moist through the operation of blinking which spreads tears across the eye’s surface.

Question 25

What is the role of eye lashes?

Answer 25

To help filter out dust and debris and prevent sweat from getting into the eye

Question 26

Describe the Sclera of the eye?

Answer 26

the protective outer wall of the eye

Question 27

Describe what the Sclera is made up of?

Answer 27

strong, fibrous tissue that expands from the cornea to the optic nerve.

Question 28

Describe what the sclera gives to the eye?

Answer 28

its white colour and its shape.

Question 29

Name the muscle that the sclera is attached to?

Answer 29

the extraocular muscle

Question 30

What is the role of the extraocular muscle?

Answer 30

it moves the eye from side to side, up and down and diagonally.

Question 31

Describe the conjunctiva of the eye?

Answer 31

a thin transparent layer of skin

Question 32

Where do you find the conjunctiva of the eye?

Answer 32

begins at the outer edge of the cornea, covers the outer part of the sclera and coats the inside of the eyelids.

Question 33

What does the conjunctiva of the eye produce?

Answer 33

A thick clear fluid.

Question 34

what does the thick clear fluid that the conjunctiva produces do?

Answer 34

lubricates the eye as well as produces some tears which help keep bacteria and foreign material from getting into the eye.

Question 35

What is the conjuntiva made up of?

Answer 35

microscopic blood vessels

Question 36

What happens to the microscopic blood vessels when the eye becomes irritated, injured or infected?

Answer 36

the blood vessels become dilated and make the eye look red.

Question 37

Describe the cornea?

Answer 37

clear dome-shaped layer at the front and centre of the eye in front of the iris

Question 38

What is the main role of the cornea?

Answer 38

to help bend or refract light into the lens as it enters the eye

Question 39

What percentage of the eyes ability to focus comes from the cornea?

Answer 39

70%

Question 40

Describe the role of the cornea?

Answer 40

acts as a filter to screen out the most damaging ultraviolet (UV) waves present in sunlight

Question 41

Where do you find the anterior chamber of the eye?

Answer 41

immediately behind the cornea and the iris.

Question 42

Is the anterior chamber the fluid filled space?

Answer 42

Yes it is

Question 43

What is the name of the fluid filled space found in the anterior chamber?

Answer 43

aqueous humour

Question 44

What does the aqueous humour fluid found in the anterior chamber provide cornea and the lens of the eye?

Answer 44

nourishment

Question 45

What does the iris control?

Answer 45

the amount of light that enters the eye

Question 46

Describe the iris?

Answer 46

a circular shape with a round opening in the centre known as the pupil.

Question 47

What colour can the iris be?

Answer 47

green, blue, brown or a mixture

Question 48

What does a ring of muscles around the iris allow?

Answer 48

it allows the pupil to contract in bright light and expand in darkness or dim light

Question 49

Name two extreme emotional circumstances that the pupil dialates to?

Answer 49

1. fear | 2. pain

Question 50

Describe where you find the posterior chamber within the eye?

Answer 50

in front of the lens and behind the iris

Question 51

Where in the eye do you find the lens?

Answer 51

just behind the the iris and the pupil

Question 52

Name the fluid found in the posterior chamber?

Answer 52

aqueous humour

Question 53

Describe the lens of the eye?

Answer 53

a clear flexible structure

Question 54

Name what produces the fluid aqueous humour?

Answer 54

ciliary body

Question 55

Describe how aqueous humour fluid within the posterior chamber works?

Answer 55

The aqueous humour fluid moves throught the posterior chamber and then forward through the pupil into the anterior chamber

Question 56

Describe what the ciliary body is responsible for?

Answer 56

ciliary body contracts, the lens thickens, increasing the ability to focus up close.

Question 57

What does the ciliary body do when looking at an object at a distance?

Answer 57

it relaxes and the lens thins out.

Question 58

What happens to the ciliary body as we age?

Answer 58

the body muscle and lens gradually lose elasticity.

Question 59

Where do you find the vitreous cavity in the eye?

Answer 59

behind the lens and in front of the retina

Question 60

Is the vitreous cavity filled with jelly-like fluid?

Answer 60

Yes

Question 61

What is the name of the jelly-like fluid found in the vitreous cavity?

Answer 61

vitreous humour

Question 62

What is the role of the vitreous humour fluid?

Answer 62

to help maintain the shape of the eyeball

Question 63

Where in the eye do you find the retina?

Answer 63

at the back of the eye

Question 64

What does the retina contain?

Answer 64

a layer of cells

Question 65

What is the role of the layered cells found in the retina?

Answer 65

to convert light into nerve signals which are then transferred via the optic nerve to the brain where the image is processed and we 'see' an object.

Question 66

Name two types of cells or photoreceptors that make up the retina?

Answer 66

1. rods | 2. cones

Question 67

What is the role of the rods?

Answer 67

rods are sensitive to light allowing vision in dim light.

Question 68

Do rods allow colour to be detected?

Answer 68

no

Question 69

What do cones provide?

Answer 69

colours sensitivity but need more light

Question 70

Where in the eye do you find the macula?

Answer 70

in the centre of the retina

Question 71

What does the macula provide?

Answer 71

sharp vision in an area known as the fovea centralis, where a concentration of cones is located. This area allows the eye to see detail and perform tasks such as reading.

Question 72

Where in the eye do you find the choroid?

Answer 72

In between the retina and the sclera

Question 73

Describe the choroid?

Answer 73

a layer of tissue mainly made up of blood vessels

Question 74

What is the role of the choroid?

Answer 74

To help nourish the retina

Question 75

What is the optic nerve responsible for?

Answer 75

transmitting visual information from the eye to the visual cortex of the brain for processing into an image.

Question 76

There are 12 pairs of cranial nerves, what number is the optic nerve.

Answer 76

the optic nerve is the second nerve of 12 pairs of cranial nerves