Week 6

Question 1

What does the fibres tunic of the eye consist of?

Answer 1

anterior cornea and posterior sclera

Question 2

What type of epithelium is on the outer surface of the cornea?

Answer 2

non-keratinised stratified squamous epithelium

Question 3

What type of epithelium is on the inner surface of the cornea?

Answer 3

simple squamous epithelium

Question 4

What is the sclera made up of?

Answer 4

collagen fibres and fibroblasts

Question 5

What are the functions of the sclera?

Answer 5

gives eyeball shape
makes it more rigid
protects inner parts
serves as a site for attachment for extrinsic eye muscles

Question 6

What is at the junction of the cornea and the sclera?

Answer 6

scleral venous sinus

Question 7

What does the vascular tunic of the eye consist of?

Answer 7

choroid, ciliary body and iris

Question 8

Describe the choroid of the wye

Answer 8

lines the internal surface of the sclera
numerous blood vessels
contain melanocytes

Question 9

Describe reflexive constriction of the pupil

Answer 9

bright light stimulates the eye

parasympathetic fibres of CN II stimulate the circular muscles or sphincter pupillae of the iris to contract.

Question 10

Describe dilation of the pupil

Answer 10

dim light stimulates the eye

sympathetic neurons stimulate radial muscles dilator pupillae of the iris to contract

Question 11

What are the two forms of age-related macular degeneration?

Answer 11

Exudative and atrophic

Question 12

Describe exudative AMD

Answer 12

new blood vessels growing under retina from choroid
rapid
metamorphopsia

Question 13

Describe atrophic AMD

Answer 13

atrophy of outer retina
slow
blurring

Question 14

How does AMD lead to blindness?

Answer 14

blood vessels and scar tissue grow under the retina
leaking vessels cause retinal oedema
Block O2 and nutrients from the choroid
eventual scarring causes destruction of photoreceptors

Question 15

What is the main gene linked to AMD?

Answer 15

complement factor H

Question 16

Describe angiogenesis

Answer 16

basement membrane is degraded locally by proteases
endothelial cells migrate out forming a sprout
endothelial cells following the leading cells proliferate under the influence of VEGF

Question 17

Describe the distribution of visual fields in the brain

Answer 17

everything on the left visual field goes to right visual cortex and everything on right visual field goes to left visual cortex

Question 18

What can be caused by lesions in the optic nerve?

Answer 18

partial or complete loss of vision in ipsilateral eye

Question 19

What can be caused by lesions of the optic chiasm?

Answer 19

loss of temporal visual filed of both eyes

bitemporal hemianopia

Question 20

What can be caused by lesions of the optic tract?

Answer 20

loss of vision in the same visual field of both eyes

homonymous hemianopia

Question 21

Where do the fibres for the parasympathetic pupillary reflex go?

Answer 21

ciliary ganglio, edinger wesphal nucleus of third nerve

Question 22

Where do the fibres for the sympathetic pupillary reflex go?

Answer 22

superior cervical ganglion

Question 23

What is the afferent pathways nerve in pupillary reflexes?

Answer 23

CNII

Question 24

What is the efferent pathway nerve in the light reflexes?

Answer 24

CNIII