Development of the eye

Question 1

What is the optic vesicle?

Answer 1

An outgrowth of the eye from the neural tube

Question 2

What is the lens placode?

Answer 2

thickened portion of ectoderm that acts as a precursor to the lens

Question 3

What is the function of the outer layer (tunicae)?

Answer 3

Dense and tough collagen tissue, it protects and holds the eyeballs shape

Question 4

What is the function of the middle (vascular) tunic?

Answer 4

Contains the blood vessels and also the structures that hold the lens in place/ regulate pupil size

Question 5

What does the fibrous tunic consist of?

Answer 5

The sclera and the cornea

Question 6

What does the vascular tunic consist of?

Answer 6

Choroid, Ciliary body and the iris

Question 7

What is another word for vascular tunic?

Answer 7

Uvea

Question 8

What produces the aqueous humour?

Answer 8

It is produced by the ciliary epithelium, this fluid then fills the front chambers of the eye

Question 9

Where is the aqueous humour reabsorbed?

Answer 9

reabsorbed by the trabecular meshwork

Question 10

What is glaucoma?

Answer 10

Too much fluid building up in the eye without proper drainage

Question 11

What is the function of the nervous tunic?

Answer 11

Connected to the brain and converts light information to a nerve signal

Question 12

What is the lens composed of?

Answer 12

clear, transparent cells contained within an elastic capsule

Question 13

What is cataracts?

Answer 13

clouding of the lens

Question 14

Where does the eye sit in the skull?

Answer 14

within the bony orbit

Question 15

What is the function of the bony orbit?

Answer 15

Houses and protects the eyeball

Question 16

Binocular vision

Answer 16

In animals with front facing eyes, better depth perception but more limited field of view

Question 17

Monocular vision

Answer 17

In animals with lateral facing eyes, little depth perception but better field of view

Question 18

What are the extra-occular muscles?

Answer 18

Act together to produce/ coordinate eye movements

Question 19

What are eye-lids?

Answer 19

skin folds that cover the eye

Question 20

Where do the tear glands drain?

Answer 20

Drains through nasolacrimal duct into nose

Question 21

What keeps the third eye retracted?

Answer 21

Smooth muscle under a sympathetic influence

Question 22

What is the function of the retractor bulbi?

Answer 22

pulls the eye back into the head

Question 23

What is the cartilage at the third eyelid like?

Answer 23

T-shaped cartilage

Question 24

Where does the lens placode sit?

Answer 24

Inside of the optic cup

Question 25

What does the overlying ectoderm become?

Answer 25

The cornea

Question 26

What do the two layers of the optic cup go on to become?

Answer 26

The neural and pigmented retina

Question 27

What is the function of the cornea?

Answer 27

transparent part at the front of the eye, it allows light to enter

Question 28

What is the vascular tunic also known as?

Answer 28

The uvea

Question 29

What is the choroid and what artery supplies it?

Answer 29

The choroid is a highly vascular part at the back of the eyeball and is supplied by the opthalmic artery

Question 30

What attaches the ciliary muscle to the lens?

Answer 30

Zonules/ Zonulas

Question 31

Where is the vitreous chamber found?

Answer 31

Behind the lens

Question 32

What are the three main functions of the eyelid?

Answer 32

Blocks light, Protects the cornea and keeps the surface moist

Question 33

What does the lens vesicle induce?

Answer 33

The lens vesicle induces the overlying ectoderm to become the cornea

Question 34

What does the mesenchyme surrounding the optic cup become?

Answer 34

The fibrous and vascular layers

Question 35

What does the optic stalk become?

Answer 35

The optic stalk becomes the optic nerve

Question 36

What do the hyaloid vessels leave behind once they regress?

Answer 36

They leave behind a non-functional hyaloid canal

Question 37

What is the main function of the choroid?

Answer 37

To supply nutrients/nourish to the outer retina

Question 38

What is the iris a continuation of?

Answer 38

The iris is a continuation of the ciliary body

Question 39

What is the name of the smooth muscle that keeps the third eyelid retracted under sympathetic influence?

Answer 39

m. orbitalis

Question 40

What is the function of the top layer of the eye lid?

Answer 40

It is a lipid top layer (tarsal glands) and it prevents evaporation

Question 41

What is the function of the middle layer of the eyelid?

Answer 41

It is a watery middle layer (lacrimal gland and third eyelid) and it nourishes the cornea

Question 42

What is the function of the bottom layer of the eyelid?

Answer 42

Mucous bottom layer that sticks tear film to the eye

Question 43

What is a species difference of the retina in birds?

Answer 43

There are fewer blood vessels to 'block' the retina, therefore birds have better vision

Question 44

What are sclerotic rings and what are there function?

Answer 44

Sclerotic rings are bony plates within the eye and they function to hold the eyeball shape and counteract water pressure

Question 45

What is the name of the artery that supplies the choroid?

Answer 45

opthalmic artery

Question 46

What is the main function of the lens?

Answer 46

To keep objects in focus (accommodation)

Question 47

What are suspensory ligaments attached to?

Answer 47

Zonulas

Question 48

Where is aqueous humour reabsorbed?

Answer 48

trabecular meshwork at the iridocorneal angle

Question 49

What is derived from the outer part of the optic cup?

Answer 49

The pigmented layer of the retina

Question 50

Where do all axons from the ganglion converge?

Answer 50

at the optic nerve that takes information to the brain

Question 51

Which tear gland layer contains the third eyelid and lacrimal duct?

Answer 51

The watery middle layer

Question 52

What is the function of the mucous bottom layer of the tear gland?

Answer 52

It sticks tear films to the eye

Question 53

What is the purpose of blinking?

Answer 53

spreads tear films over the eye

Question 54

What is the organ that separates the anterior and posterior chambers?

Answer 54

The lens/ the suspensory ligaments holding it

Question 55

What is the name of the device that allows you to view the tympanic membrane when the auditry canal is straightened?

Answer 55

otoscope

Question 56

What is the name of the glands that line the external ear?

Answer 56

sebacous and modified apocrien (ceruminous) glands