The Eye Flashcards
Photoreceptors
The receptors that detect light stimuli
Outer fibrous layer of eye:
SCLERA
- white inelastic layer of connective tissue
- protects internal parts of eye
- helps to maintain spherical shape of eye
- serves for muscle attatchment
Outer fibrous layer of eye:
CORNEA
- transparent front part of sclera
- more convex than rest of eyeball
- allows light though to inner layers of eye
- NB curvature causes the refraction of incoming light rays
Middle Vascular Layer:
CHOROID
- darkly pigmented vascular layer
- Pigment absorbs light to prevent internal reflection which may cause blurred images
Middle Vascular Layer:
CILIARY BODY
Thickened front part of the choroid with involuntary muscles. These attach to the lens and can contract to change the curvature of the lens
Suspensory ligaments
A series of fibres that connect the CILIARY BODY of the eye with the lens, keeps it in place.
Middle Vascular Layer:
IRIS
- Round
- Coloured
- Has both radial and circular involuntary muscles that pull the iris open or closed
- NB THIS ALLOWS REGULATION OF LIGHT INTO THE EYE
Lens
- rubbery, elastic transparent, biconvex structure (held in place by suspensory ligaments attached to the ciliary body)
- changes shape to refract light of near and far objects onto the retina
Aqueous humours
Watery fluid in front of the lens, to maintain shape of the eye and holds the retina against the choroid
Vitreous humours
watery fluid behind the lens, similarly to the function of the aqueous humours
RETINA
pigmented layer and nerve tissue with photoreceptors that detect light stimuli and convert the stimuli into nerve impulses.
There are 2 types of photoreceptors: Rods and Cones
Rods
light sensitive and give rise to black and white vision
Cones
allow for bright light and color vision
How your eye works (FRIP)
F - focused onto retina
R - refracted light on retina is upside down
I - info sent along optic nerve
P - processed by brain so you see it normally
ACCOMMODATION
Distant Objects
concave and/or flatter
contracting ciliary muscles
suspensory ligaments relax