Eye Flashcards
What forms the outer eye?
Cornea and sclera
What is the function of the cornea?
Transmission and refraction of light
What is the function of the sclera?
- Forms white capsule of collagen around eye to offer protection.
- Serves as an insertion point for the external muscles of the eye
What forms the middle eye?
Iris, ciliary body, choroid
What is the function of the iris?
Controls size of pupil to let in varying amounts of light.
Which muscles are involved in controlling the size of the pupil?
1. Sphincter muscles They have circular fibres. They make the pupil smaller (parasympathetic) 2. Dilator muscles They have radial fibres They make the pupil larger (sympathetic)
What is the function of the ciliary body?
- Has glandular epithelium to produce aqueous humour & nutrients for the cornea
- Made of smooth muscle to control accommodation of lens
What innervation does the ciliary body receive?
Parasympathetic
What is the function of the choroid?
- Darkly pigmented to absorb stray protons.
- Important for nutrition of outer retina.
- Acts as heat sink.
What forms the inner eye?
Retina
What is the function of the retina?
Receives light from lens and converts this to neural signals. Produces vitreous humour which helps transmits light.
At what points is the retina specialised for maximal resolving power?
Fovea centralis and macula lutea.
What is the blind spot?
The optic disc. Photoreceptors are absent here.
What epithelium is found in the retina?
Retinal pigment epithelium
Name two photoreceptors and their functions.
- Rods: Vision in dim lighting; peripheral vision
2. Cones: colour vision