Eye

Question 1

What are the 3 layers of the eyeball?

Answer 1

Fibrous
Vascular
Sensory

Question 2

What does the fibrous layer consist of?

Answer 2

Cornea

Sclera

Question 3

What does the vascular layer consist of?

Answer 3

Choroid
Ciliary body
Iris

Question 4

What is the function of the cornea?

Answer 4

Provides shape to the eye and supports deeper structures.

Transparent - light entering through it is refracted.

Question 5

What is the function of the sclera?

Answer 5

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

Question 6

What is the function of the choroid?

Answer 6

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

Question 7

What is the function of the ciliary body?

Answer 7

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

Question 8

What is the function of the iris?

Answer 8

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

Question 9

What is the function of the retina?

Answer 9

Detects light

Question 10

What is the macula?

Answer 10

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

Question 11

What is cataract?

Answer 11

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

Question 12

What is the anterior chamber?

Answer 12

Everything in front of the iris.

Question 13

What is the posterior chamber?

Answer 13

Everything behind the iris.

Question 14

What is the function of aqueous and vitreous humour?

Answer 14

Maintains the pressure of the eyeball. 21mmhg.

Question 15

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

Answer 15

Optic foramen
Superior Orbital fissure
Inferior Orbital fissure.

Question 16

What is the conjunctiva?

Answer 16

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.

Question 17

What is the function of the lacrimal gland?

Answer 17

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

Question 18

What is the route of tears?

Answer 18

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

Question 19

What is the function of extraocular muscles?

Answer 19

Control the movement of the eyeball.

Question 20

What is the function of intraocular muscles?

Answer 20

Control pupil diameter.

Alter lens curvature

Question 21

What are the 6 extrinsic muscles?

Answer 21

Superior rectus
Medial rectus
Inferior rectus
Lateral rectus
Superior oblique
Inferior oblique.

Question 22

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

Answer 22

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

Question 23

What muscle is responsible for elevating the upper eyelid?

Answer 23

Levator Palpebrae Superioris.

Question 24

What is the action of the medial rectus?

Answer 24

Adduction

Question 25

What is the action of the lateral rectus?

Answer 25

Abduction

Question 26

What is the action of the superior rectus?

Answer 26

Elevation, Adduction, Intorsion.

Question 27

What is the action of the inferior rectus?

Answer 27

Depression, Adduction, Extorsion

Question 28

What is the action of the superior oblique?

Answer 28

Intorsion, Depression, Abduction

Question 29

What is the action of the inferior oblique?

Answer 29

Extorsion, Elevation, Abduction.

Question 30

What makes up the left visual field?

Answer 30

Left nasal and right temporal fibres.

Question 31

What makes up the right visual field?

Answer 31

Right nasal and left temporal fibres.

Question 32

What are the steps of the visual pathway?

Answer 32

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).

Question 33

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

Answer 33

Patient would have blindness in right eye. | Right optic nerve carries right temporal and right nasal fibres.

Question 34

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

Answer 34

Patient would have bitemporal hemianopia. | Optic chiasm is site of nasal fibre decussation so they could no longer see temporal sides.

Question 35

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

Answer 35

Patient would have contralateral homonymous hemianopia. Carries fibres from both left and right sides.