The visual system

Question 1

List the following labels within the picture

Answer 1

1) iris
2) pupil
3) Conjunctiva ( lines eyelids and surface of eye)

Question 2

Which 3 parts the eyeball can be divided into?

Answer 2

• Fibrous layers
• Vascular layers
• Inner layers

Question 3

What is the fibrous layer?

Answer 3

outermost layer
consist of sclera and cornea

The function is to provide shape to the eye and support the deeper structures

Question 4

What is a vascular layer?

Answer 4

layer underneath the fibrous layer,
consists of the choroid, ciliary body and iris

Question 5

What is choroid and its function

Answer 5

The layer of connective tissue and blood vessels
- provides nourishment to the outer layers of the retina

Question 6

What is a ciliary body and its function?

Answer 6

located between the choroid and iris
control the shape of the lens and contribute to the formation of aqueous humor

Question 7

what is iris

Answer 7

aka pupil

Diameter of the pupil is altered by smooth muscle fibres –> sphincter pupillae <– control by the autonomic nervous system

sits between the lens and the cornea

Question 8

what does the inner layer of the eye consist of?

Answer 8

retina

Question 9

What technique does Optian use to check your eye?

Answer 9

ophthalmoscopy

Question 10

What are the 2 main things you can see when an ophthalmoscope is used? (can use to image to help you out)
And what is their function?

Answer 10

Centre of the retina - macula
(its the dark area within the eye, the centre of the macula is called fovea)
*purpose –> highest concentration of light-detecting cells and area of high visual activity

optic disc –> area where the optic nerve enters

• it got no light-detecting cells in it

Question 11

what is the condition of cataract?

Answer 11

Where there is a cloudy area in the lens of your eye
its a common condition through old age

Question 12

what changes that shape of the lens

Answer 12

ciliary body

Question 13

what are the two fluids that exist in the eye?
and where are they located?

Answer 13

anterior chambers
- located between the cornea and the iris

posterior chambers
- located between the iris and ciliary processes

Question 14

what is the liquid that filled in the eye?
and function

Answer 14

aqueous humor

• nourishes and protects the eye

drains through the trabecular meshwork

Question 15

what condition can be caused if the drainage of the aqueous humor is obstructed?

Answer 15

glaucoma
group of eye diseases that result in damage to the optic nerve

Question 16

What are the 2 conditions of glaucoma?
Evaluate on cause and what will it lead to

Answer 16

Open-angle glaucoma
- the outflow of aqueous humor through the trabecular meshwork is reduced
- causes a gradual reduction of the peripheral vision

closed angle glaucoma
- iris is forced against the trabecular meshwork and prevents any drainage of aqueous humor
- lead to pressure buildup and changes in optic nerve –> lead to blindness

Question 17

what are the 7 extrinsic muscle of the eye?

Answer 17

• superior rectus
• inferior rectus
• medial rectus
• lateral rectus
• superior oblique
• inferior oblique
• 1 levator palpebrae superioris muscle (controls the eyelid)

Question 18

what is the attachments, action and innervation of levator palpebrae superioris?

Answer 18

attachments –> attaches to the superior tarsal plateof the upper eyelid

actions –> elevates the upper eyelid

innervation –> oculomotor nerve (CNIII)

Question 19

where are the recti muscles originate from?

Answer 19

common tendinous ring
fibrous tissue at the back fo the orbit

Question 20

Attachment, actions and innervation of superior rectus

Answer 20

A: superior and anterior aspect of the sclera

A: elevation, contributes to adduction and medial rotation of the eyeball

I: Oculomotor nerve (CNIII)

Question 21

Attachment, actions and innervation of the inferior rectus

Answer 21

A: inferior part of the common tendinous ring, attaches to the inferior and anterior aspects of the sclera

A: depression (moving down), contributes to adduction and lateral rotation of the eyeball

I: Oculomotor nerve (CNIII)

Question 22

Attachment, actions and innervation of medial rectus

Answer 22

A: medial part of the common tendinous ring

A: adducts the eyeball

I: Oculomotor nerve (CN III)

Question 23

Attachment, actions and innervation of lateral rectus rectus

Answer 23

A: lateral part of the common tendinous ring

A: abducts the eyeball

I: Abducens nerve (CN VI)

Question 24

oblique muscles originate from the common tendinous ring
True or false?

Answer 24

false, they have an angular approach to the eyeball and they attach to the posterior surface of the sclera

Question 25

Attachment, actions and innervation of superior oblique

Answer 25

A: originates from the body of the sphenoid bone. The tendon passes through trochlea and attaches to the sclera of the eye posteriorly A: depresses, abducts and medially rotates the eyeball I:trochlear nerve (CN IV)

Question 26

Attachment, actions and innervation of inferior oblique

Answer 26

A: originates from the anterior aspect of the orbital floor. attaches to the sclera of the eye posterior to the lateral rectus A: elevates, abducts and laterally rotates the eyeball I: Oculomotor nerve (CN III)

Question 27

answer the following extraocular muscle action Medial rectus - lateral rectus - superior rectus - inferior rectus - superior oblique - inferior oblique -

Answer 27

Medial rectus - adduction lateral rectus - abduction superior rectus - elevation, adduction, medial rotation inferior rectus - depression, adduction, lateral rotation superior oblique - depression, abduction, medial rotation inferior oblique - elevation, abduction, lateral rotation

Question 28

states the nerve supply to the extraocular muscles

Answer 28

lateral rectus is 6th CN superior oblique is 4th CN rest are all 3rd CN LR6-SO4-R3

Question 29

What are the cranial nerves associated with innervation to the eye

Answer 29

Oculomotor nerve trochlear nerve abducent nerve

Question 30

Answer the following numbers where does the oculomotor nerve branch off into?

Answer 30

1) superior rectus 2) levato palpabrae superioris 3) inferior oblique 4) medial rectus 5) inerior rectus 6) ciliary ganglion 7) short ciliary nerves

Question 31

what are the 2 structure sin teh eye that receive parasympathetic innervation from the oculomotor nerve?

Answer 31

sphincter pupillae - constricts the pupil and reduces the amount of light entering the eye ciliary muscles - contracts which cause the lens to become more spherical and thus more adapted to the short-range vision

Question 32

How does the trochlear nerve innervate the superior oblique muscle?

Answer 32

- emerges from the posterior aspect of the midbrain - exits the superior orbital fissure and enters into the orbit

Question 33

What function does the abducens nerve have and what muscle does it innervate?

Answer 33

only somatic motor function innervation to the lateral rectus muscle

Question 34

Describe optic nerve and function

Answer 34

- 2nd cranial nerve and responsible for transmitting sensory information for vision. detailed version v transmission of special sensory information from the retina of the eye to the primary visual cortex of the brain.

Question 35

optic nerve is surrounded by________?

Answer 35

cranial meninges

Question 36

which 2 components are divided from the primary visual cortex of the brain?

Answer 36

extracranial intracranial

Question 37

where is the optic nerve formed from in the extracranial? and function?

Answer 37

retinal ganglion cells receive impulses from the photoreceptors fo the eye

Question 38

pathway of extracranial

Answer 38

the nerve leaves into the optic canal and through the sphenoid bone, and along the surface of the middle cranial fossa

Question 39

what does optic nerves forms into in the intracranial

Answer 39

optic chiasm

Question 40

What fibres do the left optic tract contain?

Answer 40

Contain - left temporal (lateral) retina - right nasal (medial) retina

Question 41

What fibres do the right optic tract contain?

Answer 41

- right temporal retina - left nasal retina

Question 42

Where will the optic tract travel to, which locates in the thalamus?

Answer 42

lateral geniculate nucleus (LGN)

Question 43

How do our eyes see stuff? Evaluate the overview of the visual pathway.

Answer 43

signal of the vision travel to the optic disc v travels through the optic nerve and to the optic chiasm v then travels to the lateral geniculate nucleus (LGN) through the optic tract v Finally travel to the Primary visual cortex by the topic radiation