Eye - NAME ... Lacrimal apparatus Lacrimal gland / tear gland and duct system • modified sweat...

Click here to load reader

  • date post

    03-Aug-2021
  • Category

    Documents

  • view

    5
  • download

    0

Embed Size (px)

Transcript of Eye - NAME ... Lacrimal apparatus Lacrimal gland / tear gland and duct system • modified sweat...

• Diameter = 2.5 cm ( 1.6 cm in newborn babies)
• Weight = 6-8 gram
• Skin
• Tarsal plate : meibomian glands
( levator palpebral superiosis) opens eyes supplied by CN III
• Conjunctiva
• At the base of eyelashes : glands of Zeis & gland of moll ( inflammation: stye painful)
• Inflammation of meibomian gland producing tumor or cyst : chalazion painless
Conjunctiva Stratified epithelium columnar/ squamous
Nictitating membrane/ third eyelid
• Reduced in rabbit
Lacrimal apparatus Lacrimal gland / tear gland and duct system
• modified sweat gland)
Tear
Sclera : inflammation: scleritis
• Dense fibrous CT
• Posterior 5/6th part
• Provide attachment for EOM
• Anterior 1/6th
• 5 layers
& nutrition from aqueous humor
• Choroid
• Ciliary body
ii. Suspensory ligament/ zonules : hold the lens
iii. Ciliary muscle : accommodation (reflex that increases the curvature of lens needed for near vision )
• Iris
Iris (rainbow) diaphragm of camera Gives color to eyes - melanin
• Controls the amount of light entering the eye through the pupil
• Pattern unique to every ind.
After death pupil dilates & doesn’t respond to light
Accommodation - convergence of eyeball- constriction of pupil
Tunica nervosa/ innermost/incomplete Retina- ectodermal in origin
Outer Pigmented layer
Bipolar layer (including horizontal and amacrine,muller cell)
Ganglion cell layer
Histologically 10 layers
Ora serrata : non visual part of retina ( anterior)
Optic nerve - optic chiasm - optic tract - lateral geniculate body ( thalamus) - optic radiation - occipital cortex
But also to ,
2. Pretectal area : light reflex
3. Suprachiasmatic nucleus of hypothalamus : circadian rhythm
Rods Cones
fovea
High sensitivity but low acquity Low sensitivity but high acquity
Protein : Rhodopsin Idopsin
Lens : ectodermal in origin
• Avascular, no nerves
• Elastic , flexible , biconvex
• Due to protein deposition : cataract
Aqueous humor Vitreous humor
eyeball
• first symptom ( night blindness/ nyctalopia
• first sign( conjunctival xerosis)