Visual System

Question 1

What are the three layers of the eye?

Answer 1

Corneoscleral coat
Uveal tract
Retina

Question 2

What is the outermost layer of the eye?

Answer 2

Corneoscleral coat

Question 3

What in the middle layer of the eye?

Answer 3

Uveal tract

Question 4

What is the inner layer of the eye?

Answer 4

Retina

Question 5

What is the cornea?

Answer 5

Transparent anterior extension of sclera

Question 6

What is the vascular coat of the eye?

Answer 6

Uveal tract

Question 7

What does the uveal tract consist of?

Answer 7

Iris and ciliary body anteriorly and vascularised choroid coat posteriorly

Question 8

What does the retina consist of?

Answer 8

Layers of nerve cells, their processes, support cells and a layer of pigmented epithelium

Question 9

What is the function of a biconcave lens?

Answer 9

Elastic to allow it to change its shape to permit accommodation for near vision

Question 10

What is in front of the biconcave lens?

Answer 10

Two chambers (anterior and posterior)

Question 11

What are the anterior and posterior chamber filled with?

Answer 11

Aqueous humor

Question 12

What is posterior to the lens?

Answer 12

Vitreal cavity

Question 13

What is the vitreal cavity filled with?

Answer 13

Vitrious humor

Question 14

What is avascular and gleatinous due to collagen fibres and hyaluronic acid?

Answer 14

Vitrious humor

Question 15

What covers the optic nerves?

Answer 15

Dura and arachnoid

Question 16

How many rods does the retina contain?

Answer 16

130,000,000

Question 17

How many cones does the retina contain?

Answer 17

6,5000,000

Question 18

What does each rod contain?

Answer 18

Rhodopsin

Question 19

What does each cone contain?

Answer 19

3 opsin pigments

Question 20

Are rods and cones in the retina evenly distributed?

Answer 20

No

Question 21

What colours are the cones sensitive to?

Answer 21

Red, green and blue

Question 22

What have ‘centre surround’ receptive fields with a central circular region and a ring shaped surround?

Answer 22

Retinal Ganglion Cell Receptive Fields (RGC’s)

Question 23

RGC’s can be?

Answer 23

On centre or off centre

Question 24

What are the reasons for high visual activity?

Answer 24

Thinning of retinal layers, Lack of rods, high concentrations of cones and low convergence

Question 25

Are axons myelinated within the eye?

Answer 25

No

Question 26

Are axons myelinated after passing the lamina cribrosa?

Answer 26

Yes

Question 27

What is myelin in the optic nerve formed by?

Answer 27

Oligodendrocytes

Question 28

Visual fields of the retina are described as?

Answer 28

Nasal or temporal

Question 29

Nerve fibres from the nasal part of the retina cross at?

Answer 29

Optic chiasma

Question 30

Where do fibres from the retina project to?

Answer 30

Pretectal area and superior colliculus

Question 31

Superior colliculus functions in?

Answer 31

Saccadic eye movements

Question 32

A small number of retinal fibres leave the dorsal surface of the optic chiasma and enter what?

Answer 32

Suprachiasmatic nucleus of the hypothalamus

Question 33

Fibres from what nucleus of the thalamus reach the primary visual cortex in the geniculocalcarine tracts?

Answer 33

Lateral geniculate nucleus

Question 34

What fibres form part of the internal capsule?

Answer 34

Fibres from the lateral genicuate nucleus

Question 35

What surrounds the calcimine sulcus in the occipital cortex?

Answer 35

Primary visual cortex

Question 36

What is the primary visual cortex referred to as?

Answer 36

Area 17 of Brodmann

Question 37

What can be called the striate cortex?

Answer 37

Primary visual cortex

Question 38

What is the line of Gennari?

Answer 38

A stripe of myelinated fibres found in layer IV in the primary cortex

Question 39

How many layers is the geniculate?

Answer 39

6

Question 40

What layers of the geniculate receive visual information that has crossed from the opposite eye?

Answer 40

1, 4 and 6

Question 41

What layers of the geniculate receives uncrossed fibres?

Answer 41

2,3 and 5

Question 42

Each ocular dominate column contains?

Answer 42

A complete cycle of orientation columns

Question 43

What is hemianopia?

Answer 43

Blindness for half the field of vision in one or both eyes

Question 44

What is homonymous?

Answer 44

When vision is lost on the same visual field in both eyes

Question 45

The opposite of homonymous is?

Answer 45

Heteronymous

Question 46

Other forms of partial visual field deficit is referred to?

Answer 46

Scotoma

Question 47

Frontal eye fields are thought to be involved in?

Answer 47

Saccadic movements

Question 48

Posterior eye fields are thought to be involved in?

Answer 48

Pursuit movements