recent posts

Optic nerve

A. Direct & consensual light reflexes – Pathway

imageimage

B. Accommodation reflex
 
When the eyes are directed from a distant object to a near object:
  • Medial recti contracts (Brings convergence)
  • Lens thickens to increase the refractory power by contracting ciliary muscles
  • Pupils constrict to restrict light waves to the thickest central part of the lens

The pathway

d1
C. Corneal reflex : Light touching of the cornea or conjunctive results in blinking of the eye lids
Cornea or Conjunctiva
clip_image001
Ophthalmic branch of the TGN
clip_image001
Main sensory ganglion of the TGN
clip_image001
Internuncial neurons connect with the motor nucleus of the facial nerve on Both sides (Through the medial longitudinal fasciculus)
clip_image001
Facial nerve
clip_image001
Orbicularis oculi of both sides
clip_image001
Closure of the eyelids

D. Visual body reflex

image

Effects of visual body reflexes
  • Automatic scanning movements of the eyes & head that are made when reading
  • Automatic movements of the eyes, head & neck towards the visual stimulus
  • Protective closing of the eyes & raising arm for protection
Optic nerve Optic  nerve Reviewed by Radiology Madeeasy on August 08, 2010 Rating: 5
Powered by Blogger.