Intraocular Anatomy Flashcards
(41 cards)
Name the three tunics of the ocular globe
Nervous. Vascular, Fibrous
What are the three parts of the fibrous tunic
Cornea, Sclera, Limbus
Describe features of the cornea
Anterior 1/4 of globe Optically clear Avascular Highly innervated
Cornea
Describe features of the sclera
Posterior 3/4 of globe White dense connective tissue Opaque Vessels penetrate sclera to supply deeper tunics
Describe the limbus
Junction of the cornea and sclera Attachment site of bulbar conjunctiva
What is the vasculature for the fibrous tunic
Conjunctival vessels
scleral vessels
List the three components of the vascular tunic
Choroid (posterior part)
Ciliary body and Iris (anterior part)
What is another name for the vascular tunic
Uvea or Uveal tract
Describe the choroid
Superficial to visual retina
Pigmented
Contains tapetum lucidum
Highly vascular - vascular supply to the retina
Describe the ciliary body
Anterior to choroid
Superficial to non visual retina
Has radially oriented processes
Has ciliary process and ciliaris muscle
Describe the iris
Anterior to ciliary body
Superficial to non visual retina
Forms the pupil
Describe the tapetum lucidum
Specialized reflective layer
Increases light reaching retina
Allows for night vision
Absent in pigs and humans
Describe the ciliary process
Radially oriented extensions of the ciliary body Site of attachment of zonule fibers
Describe the ciliaris muscle
Muscle deep within ciliary body
Contraction draws ciliary body centrally
Lowers tension on zonule fibers - causes lens to become convex (look at nerby objects)
Parasympathetic innervation- CN III
Describe the iris
Forms the pupil
The pupil controls the amount of light that reaches the retina
Choroid
iris muscles controls pupil size: iris dilator and constrictor
Describe the iris dilator m
Radial muscle fibers Contraction increases pupil size “Mydriasis”- large pupil size Sympathetic innervation
Describe the iris contrictor m
Circular muscle
Contraction decreases pupil size
“Miosis”- small pupil size
Parasympathetic innervation- CNIII
What are the boundaries of the anterior chamber
From the cornea to the iris
What are the boundaries of the posterior chamber
Iris to lens
What structure holds the anterior chamber open so as not to disrupt flow of aqueous humor
Pectinate lig
Describe the arrangement of the iris contrictor muscle fibers in the cat
Sine wave
What are iridic granules
Normal vascular structures on superior aspect or iris margin of horses and bovine
Purpose to to absorb extra light/protect
Note: on both superior and inferior for camelids
What is another name for the nervous tunic and what are the three components of it
The retina
Pars optica retinae, pars ciliaris retinae, pars iridica retinae
Describe the pars optica retinae
Lines deep aspect of the choroid
The ‘Visual Retina’
Contains light sensing cell layers