The Eyeball Flashcards
What do the sclera and cornea make up?
Fibrous Outer Layer
What make up the fibrous outer layer?
Sclera and Cornea
What do the Iris, Choroid and Ciliary Body make up?
Vascular Middle Layer / UVEA
What is a name for the Iris, Choroid and Ciliary Body?
The UVEA
What makes up the vascular middle layer?
Iris, Choroid and Ciliary Body
What makes up the Sensory inner layer?
Retina
What is the sclera’s role?
It provides attachment for the extraocular muscles. Venous drainage comes out the sclera and blood vessels have gaps in the sclera to get through.
It’s covered in the same meninges as those from the brain.
How many dioptres of refraction do the cornea and lens provide respectively?
Cornea - 43D
Lens - 10-15D
What are the layers of the cornea?
Epithelium - Anterior layer. Able to repair.
Bowmans
Stroma - majority of cornea, can become filled with fluid that impairs vision
Descements
Endothelium - Fluid resistant, stops fluid from the the eye reaching the cornea
= EBSDE
Describe the Iris
Thin, contractile diaphragm to affect pupil aperture. Split into anterior and posterior:
Anterior Iris - coloured part
Posterior Iris - Behind the eye, the lens is pressed against the posterior surface of the iris
The Iris is peripherally attached to the anterior surface of the ciliary body
The iris sphincter muscle is controlled by the short ciliary nerves which is a branch of CN III whereas the dilator is controlled by the sympathetic long ciliary nerves
Describe the ciliary bodys epithelium in relation to the choroid
Continues posteriorly with the choroid
Describe the ciliary bodys position in relation to the peripheral margin of the iris
Anteriorly
What are the 3 parts of the ciliary body called?
Ciliary Proper, Ciliary Processes, Ciliary Epithelium
Describe the ciliary proper
It’s made up of the ciliary muscle which, when contracted, allows for the lens to thicken
Describe the ciliary processes
Extension of the ciliary body - between the processes are the zonules that attach to the lens
Describe the ciliary epithelium
2 layers and secretes aqueous humour
What is the choroid?
Thin brown lining on the inner surface of the sclera extending from the optic nerve to ciliary body (thick at the back, thin to the front). It’s a vascular structure providing nourishment to the outer retinal layers
What makes up the inner sensory layer?
The retina. One layer of the retinal pigmented layer rests against the choroid
What is the anterior chamber?
The area between the cornea and anterior iris
What is the posterior chamber?
Between the posterior iris and ciliary processes