Visual System Flashcards Preview

Neuroanatomy > Visual System > Flashcards

Flashcards in Visual System Deck (15)
Loading flashcards...
1
Q

What are the three layers of the eye?

A
  1. Corneoscleral coat
  2. Uveal tract
  3. Retina
2
Q

Describe the corneoscleral coat

A
  • Outermost layer of the eye
  • Transparent anterior extension of the sclera
3
Q

Describe the uveal tract

A
  • Middle layer of the eye
  • Vascular coat
  • Consists of iris and ciliary body anteriorly and vascularised choroid coat posteriorly
4
Q

Describe the retina

A
  • Innermost layer of the eye
  • Consists of layers of nerve cells, their processes, support cells and on the outside, a layer of pigmented epithelium.
5
Q

Describe the lens

A
  • Biconcave disc
  • Elastic to allow change in shape to permit accommodation for near vision.
6
Q

What lies in front of the lens?

A
  • 2 chambers filled with aqueous humour.
    • An anterior chamber and a posterior chamber.
7
Q

What lies behind the lens?

A

The much larger vitreal cavity filled with vitreous humor, which is avascular and gelatinous due to collagen fibres and hyaluronic acid.​

8
Q

What are the reasons for high visual acuity in the fovea centralis?

A
  • Thinning of retinal layers
  • Lack of rods, high concentration of cones
  • Low convergence
9
Q

At what point do the axons of the optic nerve become myelinated?

A

Not myelinated within the eye, but are myelinated after passing the lamina cribrosa.

10
Q

What forms myelin in the optic nerve?

A

Oligodendrocytes

11
Q

What is the primary visual cortex also known as?

A
  • Striate cortex
  • Because a prominent stripe of myelinated fibres are found in layer 4 which can be seen with the naked eye.
  • Called the line of Gennari
12
Q

Where is information from the lower visual field projected to?

A

The gyrus superior to the calcarine sulcus

13
Q

Where is information from the upper visual field projected to?

A

The gyrus inferior to the calcarine sulcus

14
Q

Where does the macula project to?

A

The posterior pole of the visual cortex - it occupies a much greater portion of the cortex relative to the size of the visual field it covers.

15
Q
A