describe the anatomy and function of the human eye, including the:
- conjunctiva
- cornea
- sclera
- choroid
- retina
- iris
- lens
- aqueous and vitreous humor
- ciliary body
- optic nerve
Structure of the eye National Centre of Research Resources, Washington, USA.
Structure | Anatomy and Function |
---|---|
conjunctiva | continuation of the epidermis of the skin; protects the cornea at the front of the eyeball against friction |
cornea | transparent to admit light; refracts light to help form an image on the retina |
sclera | the white of the eye, a tough coat of fibres; protects the eyeball against mechanical damage, maintains shape of eyeball |
choroid | a membrane containing pigment and blood vessels; nourishes retina and prevents internal reflection |
retina | contains light-sensitive receptor cells connected to sensory neurones; detects light |
iris | a pigmented muscular structure; contracts and dilates to adjust the amount of light entering the eye |
lens | a flexible transparent structure which allows light to enter the rear of the eye; refracts light to allow fine focusing of an image onto the retina |
aqueous humor | a watery fluid; maintains the shape of the eye |
vitreous humor | a jelly-like fluid; maintains the shape of the eye |
ciliary body | contains muscles; supports the lens and alters the shape of the lens |
optic nerve | consists of bundles of sensory neurons; transmits impulses generated in the retina to the brain |