1. Epidermis - Pathogens, Melanin - UV rays, Dermis + Adipose - Mechanical Damage.
2. Sweat - water, salt, urea, ammonia, uric and lactic acid.
3. Absorbs Ca + P from blood to strengthen bones.

5. Adipose Tissue - insulator + energy store. Shock absorbers - protect against mechanical injury.

6. Important in maintaining internal environment for efficient metabolism

Fovea: cones only. Area of sharpest vision.
Blindspot: exit point of optic nerve. Insensitive to light.
Optic Nerve: axons. Carry electrical impulses to cerebrum.

Suspensory Ligaments: Attach to ciliary body of lens. Transfer pull of ciliary body to lens.
Lens: focus light on retina
Iris: coloured part. Controls amount of light entering.

HOW LIGHT ENTERS THE EYE?
Light passes through the cornea and pupil. ciliary muscle acts on lens to change the shape so the image can be focused on the retina. Image passed from retina to brain via optic nerve.