Anatomy & Physiology Flashcards
What are the tunics of the eye?
- Fibrous Tunics (Sclera, Cornea)
- Vascular Tunic (Choroid, Ciliary body, Iris)
- Retina (Pigmented layer, Neural layer)
Where is the anesthetic injection for eye lids done?
submuscular areolar tissue - lies deep to orbicularis oculi
What is the biggest oil producing gland of our body?
meibomian gland
Which nerves have to be affected for palsy in eye lid + what is the consequence?
orbicularis muscle -> CN. VII (->ectropion lower lid, but not a ptosis)
levator muscle -> CN. III (ptosis (+))
Which nerves of the eye reach the lid not from within the orbit?
facial nerve
Do the eyelids have a good healing after trauma?
yes, since:
supplied by:
external carotid a. via face
internal carotid a. via orbit
What can be used as a useful sign of infective eyelid swelling?
Lymphadenopathy-> preauricular node
-> submandibular node
especially viral! (adenoviral infection)
How is swelling of conjunctiva called?
chemosis
Which part of the tear film component is not affected by the conjunctiva?
phospholipid part
hangi gland conjuctivada bulunmaz
meibomian
Mucin secretors: Goblet cells, Henle, Manz
Accessory lacrimal glands:
Krause and Wolfring
Meibomian eyelidte sebase gland
Sensory innervation of conjunctiva?
ophthalmic division of trigeminal n.
How can contact lense form ulcers in cornea?
d/t prevention of oxygen diffusion from tear film
How long does the replacement of the cornea take + which cells?
basal cell
-> 7 days for entire corneal epithelium
What can form a bullous keratopathy?
d/t endothelial cell los through ageing and cataract surgery
-> endothelial cells needed to maintain corneal dehydration: so it swells & loses transparency
What happens in the congenital Nasolcarimal duct obstruction; “at birth watery eyes”
tears pass from lacrimal sac to nasolacrimal duct to nasopharyngeal cavity via inf. meatus
if not eyes become watery
acquired obstruction of nasolacrimal duct a common cause of watery eye in adults
-> can lead to cellulitic swelling just below medial palpebral ligament
adult comes with cellulitic swelling just below medial palpebral ligament; what to think
acquired obstruction of nasolacrimal duct
What does presbyopia describe?
failure of accomodation d/t age
-> loss of capsule elasticity
lens deformability
Where does the aqueous humour drain?
through trabecular meshwork drains into schlemm’s canal
Compare cones with rods
cones: at macule, fine vision and colour appreciation
rods: low light levels, movement, entire retina
Where is the blood-retinal barrier located?
inner BRB: between endothelial cells of retinal vessels
outer BRB: between RPE cells
Disruption of BRB can lead to?
diabetic retinopathy uveitis
What is the blow-out fracture?
decompression through fracture of the floor or medial wall minimises damage to eyeball
A fracture of the floor of the orbit can lead to abormal sensation where?
to the cheek
-> entry of maxillary division of 5th C.N.
EOM innervation
mneomic:
SO-4, LR-6, All the rest 3
Compare pressure on the chiasm with behind the chiasm
on chiasm by pituitary tumor: a bitemporal hemianopia
behind (retrochiasmal): unilateral lesion causes a hemianopia on opposite side
What supplies the optic tracts and radiation; visual cortex; macula
optic tracts and radiation: middle cerebral a.
visual cortex: post. cerebral a.
macula: dual blood supply (middle & post. cerebral a.)
