Eye (not detailed)

• What is the outer fibrous layer of the eye called?

  Posterior sclera
• What is the primary composition of the posterior sclera?

  Dense connective tissue, mostly collagen fibres
• What is the function of the sclera?

  Gives spherical shape and rigidity to eyeball
• What is another name for the scleral venous sinus?

  Canal of Schlemm
• Where does the aqueous humour drain?

  Into the scleral venous sinus
• What are the extrinsic eye muscles?

  • 3 pairs of muscles
  • Originate from posterior bony orbit
  • Insert into sclera
  • Include superior, inferior, lateral, medial rectus, and oblique muscles
• Which cranial nerves innervate the extrinsic eye muscles?

  CN III, CN IV, CN VI
• What is the role of the choroid in the eye?

  • Lines most of internal surface of sclera
  • Highly vascular
  • Provides nutrients to internal surface of sclera
• What does the ciliary body consist of?

  Ciliary processes and ciliary muscle
• What is the function of the ciliary muscle?

  Alters shape of lens for focusing
• How do the circular and radial muscles of the iris respond to bright light?

  Circular muscles contract
• What happens to the pupil in dim light?

  Radial muscles contract
• What is the optic disc?

  Site where optic nerve exits the eyeball
• What is the significance of the macula lutea?

  Area of maximum visual acuity
• What type of cells are rods and cones?

  Photoreceptor cells
• What is the primary function of rods?

  Dim light vision in shades of grey
• What is the primary function of cones?

  Color vision
• What is the lens made of?

  Layers of protein fibres called crystallins
• What is the function of the lens?

  Focus light onto retina for clear images
• What is accommodation in the lens?

  Adjustment of lens shape for vision
• What is a cataract?

  Loss of lens transparency
• What are the anterior and posterior chambers of the eye?

  • Anterior Chamber: between cornea and iris
  • Posterior Chamber: behind iris and in front of lens
  • Both filled with aqueous humour
• What produces intraocular pressure?

  Aqueous humour filtering from blood capillaries
• What is the function of the vitreous cavity?

  • Holds retina against choroid
  • Contains jelly-like vitreous body
  • Does not replenish like aqueous humour
• What are the accessory structures of the eye?

  • Eyelids (palpebrae)
  • Conjunctiva
  • Eyelashes and eyebrows
  • Lacrimal apparatus
• What is the function of the lacrimal apparatus?

  Produces and drains lacrimal fluid
• What does lacrimal fluid contain?

  Salts, mucus, and lysozyme
• What is the diameter of the adult eyeball?

  About 2.5 cm
• What are the relations of the eyeball?

  • Superior: Frontal bone
  • Inferior: Maxilla and zygoma bones
  • Medial: Ethmoid and lacrimal bones
  • Lateral: Zygoma bone
• What are the three layers of the eyeball?

  • Outer layer: Fibrous Tunic
  • Middle layer: Vascular Tunic or Uvea
  • Inner layer: Retina
• What is the composition of the outer fibrous layer?

  • Avascular
  • Consists of anterior cornea and posterior sclera
  • Covers iris and focuses light rays
• What type of epithelium covers the outer surface of the cornea?

  Non-keratinised stratified squamous epithelium
• What is the middle coat of the cornea made of?

  Collagen fibres and fibroblasts
• What type of epithelium is found in the inner coat of the cornea?

  Simple squamous epithelium