sense organs Flashcards
1
Q
conjunctiva
A
Exposed part of the eye is protected by a thin membrane
2
Q
Sclera
A
- Protects inner structures
- Maintains shape of eye
3
Q
Cornea
A
- Transparent, permits light to enter eye
- Refracts lights rays as to focus them on retina
4
Q
Choroid
A
Pigmentation prevents reflection of light within the eye
5
Q
Suspensory ligaments
A
Holds lens in position
6
Q
Ciliary muscles
A
Alters shape of lens to “accommodate” for near or far objects
7
Q
Iris
A
Contains radial and circular muscles which control amount of light entering the eye
8
Q
Retina
A
- Light sensitive layer(has photoreceptor rod/cone cells) so is responsible for image formation
- Rod Cells responsible for images in dim light
- Cone Cells responsible for images in bright light and for colour vision
9
Q
Lens
A
- Transparent therefore refracts light focusing it on retina
- Ability to change shape for near or distant vision
10
Q
Aqueous Humour
A
- Maintains shape of the cornea
- Supplies lens and cornea with food and oxygen
- Minor role in refraction
11
Q
Vitreous Humour
A
Maintains shape of eyeball
12
Q
Lens shapes for distant vision
A
- ciliary muscles relaxed
- lens flattened
- suspensory ligments taut
13
Q
lens shape for near vision
A
- ciliary muscles contract
- lens thickened, more spherical
- suspensory ligaments slacken
14
Q
pupils in dim light
A
- radial muscles of iris contract
- circular mucles relax
- pupils dilate
- light in eye increases
15
Q
pupils in bright light
A
- circular muscles of iris contract
- radial muscles relax
- pupil constricts
- light in eye reduces
