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Neurology > Eye > Flashcards

Flashcards in Eye Deck (35)
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1
Q

What are the 3 layers of the eyeball?

A

Fibrous
Vascular
Sensory

2
Q

What does the fibrous layer consist of?

A

Cornea

Sclera

3
Q

What does the vascular layer consist of?

A

Choroid
Ciliary body
Iris

4
Q

What is the function of the cornea?

A

Provides shape to the eye and supports deeper structures.

Transparent - light entering through it is refracted.

5
Q

What is the function of the sclera?

A

Provides attachment for the extraocular muscles of the eye that control its movement.
White part of the eye.

6
Q

What is the function of the choroid?

A

Layer of connective tissue and blood vessels that supplies the outer layers of the retina with nutrients.

7
Q

What is the function of the ciliary body?

A

Suspends and controls the lens shape (accommodation) and produces aqueous humour.

8
Q

What is the function of the iris?

A

Contains smooth muscle fibres that control the diameter of the pupil. Innervated by the autonomic nervous system.

9
Q

What is the function of the retina?

A

Detects light

10
Q

What is the macula?

A

The centre of the retina. It is highly pigmented and has many light detecting cells.
Contains a depression called the Fovea - highest vision acuity.

11
Q

What is cataract?

A

When the lens becomes opaque. Normally due to old age.

12
Q

What is the anterior chamber?

A

Everything in front of the iris.

13
Q

What is the posterior chamber?

A

Everything behind the iris.

14
Q

What is the function of aqueous and vitreous humour?

A

Maintains the pressure of the eyeball. 21mmhg.

15
Q

What are the 3 openings at the apex of the eye?

A

Optic foramen
Superior Orbital fissure
Inferior Orbital fissure.

16
Q

What is the conjunctiva?

A

Mucous membrane that covers the front of eye and lines the insides of the eyelids.
Keeps the eyes moist so they can open and close easily - contains goblets cells within its epithelium.

17
Q

What is the function of the lacrimal gland?

A

Serous exocrine glands
Located in orbital fossa.
Secretes tears which act to lubricate and protect the cornea.

18
Q

What is the route of tears?

A

lacrimal gland - lacrimal duct - punctae - cannaliculi - lacrimal sac- Nasolacrimal duct - inferior meatus.

19
Q

What is the function of extraocular muscles?

A

Control the movement of the eyeball.

20
Q

What is the function of intraocular muscles?

A

Control pupil diameter.

Alter lens curvature

21
Q

What are the 6 extrinsic muscles?

A
Superior rectus
Medial rectus
Inferior rectus
Lateral rectus
Superior oblique
Inferior oblique.
22
Q

What is the innervation of the extrinsic muscles of the eyeball?

A

Superior oblique - CN IV trochlear
Lateral Rectus - CN VI abducent
Everything else - CN III oculomotor.

23
Q

What muscle is responsible for elevating the upper eyelid?

A

Levator Palpebrae Superioris.

24
Q

What is the action of the medial rectus?

A

Adduction

25
Q

What is the action of the lateral rectus?

A

Abduction

26
Q

What is the action of the superior rectus?

A

Elevation, Adduction, Intorsion.

27
Q

What is the action of the inferior rectus?

A

Depression, Adduction, Extorsion

28
Q

What is the action of the superior oblique?

A

Intorsion, Depression, Abduction

29
Q

What is the action of the inferior oblique?

A

Extorsion, Elevation, Abduction.

30
Q

What makes up the left visual field?

A

Left nasal and right temporal fibres.

31
Q

What makes up the right visual field?

A

Right nasal and left temporal fibres.

32
Q

What are the steps of the visual pathway?

A

1 - Optic nerve leaves eye
2- Optic nerves join at optic chiasma.
3- Nasal fibres cross over to contralateral side
4- Optic tracts split from chiasma
5- Fibres synapse at Lateral Geniculate Body of thalamus
6- Optic radiation then travels to Primary visual cortex (area 17).

33
Q

What would happen to an individuals eye sight if they suffered a right optic nerve lesion?

A

Patient would have blindness in right eye.

Right optic nerve carries right temporal and right nasal fibres.

34
Q

What would happen to an individuals eye sight if they suffered from a pituitary adenoma compressing on their optic chiasma?

A

Patient would have bitemporal hemianopia.

Optic chiasm is site of nasal fibre decussation so they could no longer see temporal sides.

35
Q

What would happen to an individuals eye sight if they suffered an optic tract or optic radiation lesion?

A

Patient would have contralateral homonymous hemianopia.

Carries fibres from both left and right sides.