BIOLOGY EYE STRUCTURE 🚨🚨🚨

academic comeback?

Cornea

Transparent; no blood vessels, oxygen diffuses it from outside air

Refracts light , allows light into the eye

Iris

Controls how much light enters the pupil

Pupil

Gap in iris that allows light pass through to the lens

Lens

Changes shape to focus light onto the retina

Rod cells

Sensitive to light, can only see black and white

I.e can’t see colour in the dark

Cone cells

Sensitive to colour of light, allow us to see colour

Fovea

Area of retina with high concentration of cone cells, provides sharp vision

Optic nerve

Transmits impulses to the brain

Virtreous humour

Maintains shape of eye and attaches to retina

Aqueous humour

Maintains pressure in eye and nourishes cornea

Ciliary muscles

Help change the shape of of the lens in accommodation

Adaptations of neurones

Adapted to carry electrical impulses from one point to another

They are:

Long

Thin

Many branched connection to allow them to pass information

Sclera

Tough outer coat of the eye

Chloroid

Dark layer, pigmented to prevent light form being reflected around the eye

Nervous system (vs encodrine/hormonal system)

• sends fast impulses

• Short lived effect

• Localised effect

Endocrine system (vs nervous system )

• hormones in bloodstream

• Slower

• Longer-lasting

• Generalised effect

In bright light:

• circular muscles contract

• Radial muscles relax

• Pupil constricts

In dim light:

• circular muscles relax

• Radial muscles contract

• Pupils dilate