Describe the functions of the various parts of the human eye

- Sclerotic/ sclera- it is made up of collagen fibres thus protects the eye and also maintains the shape of eyeball.
- Cornea- allows light to enter the eye also it
refracts light towards retina.
- Conjunctiva- protects cornea and the entire eyeball
- Eyelids- protects cornea from mechanical or chemical damage/ protect eye from entry of foreign particles also protects retina from bright light
- Choroids – ( contain black pigment which) prevents reflection of light within the eye/ absorbed light. It also nourishes the eye or retina by supplying oxygen and removing carbon (IV) oxide.
- Ciliary muscles- alter shape of lens during accommodation. Also the
ciliary body produces aqueous humour.
- Suspensory ligaments- adjust shape of lens during accommodation.
- Lens – refracts light rays or focuses light on retina
- Vitreous humour or aqueous humour – nourish cornea and the lens, refracts light
- Iris – it is pigmented thus gives the eye it colour. It absorbs light and also controls amount of light entering the eye by adjusting the size of pupil.
- Pupil- light enters the eye through pupil
- Retina – has photoreceptor cells (i.e rods and cones) which
cause image formation as they generate impulses.
- Forea/yellow spot- visual acuity most sensitive part of retina with only cones.
- Blind spot- a point where nerve fibre emerges from the optic nerve/ where the optic nerve leaves the eye.
- Optic nerve- transmit impulses to brain for interpretation