Lecture 13 Flashcards
What are the three layers of the eye?
Corneoscleral coat, uveal tract and retina
What is the outermost layer of the eye?
Corneoscleral coat
What is the middle layer of the eye?
Uveal tract
What is the inner layer of the eye?
Retina
What is a transparent anterior extension of the sclera?
Cornea
What is the vascular coat?
Uveal tract
What does the uveal consist of?
Iris and ciliary body anteriorly and choroid coat posteriorly
What is the inner layer of the eye?
Retina
What does the retina consist of?
Layers of nerve cells, their processes, support cells and a layer of pigmented epithelium
What is the function of the biconvex lens?
Elastic to allow it to change its shape to permit accommodation for near vision
What is infront of the biconvex lens?
Anterior and posterior chamber
What fills the anterior and posterior chambers?
Aqueous humor
What structure lies posterior to the lens?
Vitreal cavity
What is the vitreal cavity filled with?
Vitrious humor
Why is the vitrious humor avascular and gelatinous?
Due to collagen fibres and hyaluronic acid
What is it called when the flow of aqueous humor is disrupted?
Glaucoma
What part of the eye contains rods and cones?
Retina
What does each rod contain?
Rhodopsin
What does each cone contain?
3 opsin pigments
What colours are cones sensitive to?
Red, green or blue light
What are reasons for high visual acuity?
Thinning of retinal layers
lack of rods, high concentrations of cones
low convergence
Are axons myelinated in the eye?
No
When do axons become myelinated in the eye?
After passing the lamina cribrosa
Myelin in the optic nerve is formed by?
Oligodendrocytes
What surrounds the optic nerve?
Meninges
Superior colliculus functions in?
Saccadic eye movements
What parts of the eye receive information from the contralateral visual field?
Optic tract and lateral geniculate nucleus
Where do the fibres from the lateral geniculate nucleus of the thalamus reach the primary visual cortex?
Geniculocalcarine tracts
What does the primary visual cortex surround?
Calcarine sulcus in the occipital cortex
What is referred to the area of Brodmann?
Primary visual cortex
What is called the striate cortex?
Primary visual cortex
What layers of the lateral geniculate nucleus receive visual information that has crossed from opposite eyes?
1, 4 and 6
What layers of the lateral geniculate nucleus receive uncrossed fibres?
2,3 and 5
What is hemianopia?
Blindness for half the field of vision in one or both eyes
What does the frontal eye field control?
Movements of command
Posterior eye fields are thought to be involved in?
Pursuit movements
