Chapter 14- Ocular anatomy and physiology part 1 (3) Flashcards
What is the uvea made up of?
1- Choroid
2- Ciliary body
3- Iris (that forms the pupil)
What is the choroid?
This is a vascular layer sandwiched between the sclera and retina.
What is the function of the choroid?
Its main function is to supply nutrients to the outer retina.
What is the Bruch’s membrane?
Seperates the choroid and the retina.
Why is the Bruch’s membrane particularly important?
Because this is where Drusen (metabolic waste) is deposited and prevents drusen from accumulating.
Where does the ciliary body extend between?
The choroid and iris
What are the main functions of the ciliary body?
1- To control the shape of the lens
2- To produce the aqueous humour
The surface of the ciliary body is divided into two regions:
1- Anterior pars pilcata
2- Posterior pars plana
What is the pars plana?
This is a flat extension from the posterior aspect of the ciliary body to the ora serrata
Lens zonules are used to control what?
Accommodation
What do the lens zonules run along and what are they anchored to?
They run along the pars plana surface and are anchored to the ora serrata.
What is the pars pilcata?
A ring of 70- 100 ciliary processes (ridges).
Each ciliary process is covered by what?
A 2 layered epithelium called the ciliary epithelium bilayer.
What are the two layers of epithelium in the ciliary process?
1- Unpigmented epithelium- produces aqueous humour
2- Pigmented epithelium- contain melanin granules and trap light
Interference with the drainage of aqueous humour results in what?
A build-up of pressure within the eye.
This will put pressure on the optic nerve, damaging the axons within it, and eventually leading to loss of sight.
This is one form of glaucoma.
The bulk of the ciliary body is made of what?
Ciliary muscle
What form of muscle is a ciliary muscle?
A smooth muscle
The posterior surface of the iris is covered by what and what does this ensure?
Covered by a 2 layered epithelium containing melanin.
This ensures that only light that enters the eye is through the pupil.
What type of connective tissue is the stroma of the iris and what does this allow?
Loose areolar connective tissue.
Allows it to change shape.
The iris contains 2 smooth muscles:
1- The iris sphincter- constricts the pupil
2- The iris dilator- opens up the pupil
What is the pupil?
The dark circular opening in the centre of the iris, where light enters the eye.
What does the pupil control?
Controls the amount of light entering the eye.
