Anatomy of the Eye Flashcards
Which wall and bones are commonly fractured?
The medial wall
Sphenoid
Lacrimal
What is the function of the cornea?
Bends light - refracting it
What is the choroid?
A layer of blood vessels beneath the retina
What happens if you lose the corneal endothelium?
It doesn’t come back (those cells don’t divide)
Eye swells - v. painful
Which muscle elevates the eyelid?
Levator palpebrae superiosis
How does the entry of the optic nerve appear?
White disk
Which arm of the NS innervates sphincter pupillae?
Parasympathetic
Which muscles control the aperture of the eye?
Spincter papillae: constricts the pupil
Dilator papillae: dilates the pupil
What causes presbyopia?
The lens looses flexibility
Which bones make up the lateral aspect of the orbit?
Zygomatic
Greater wing of the sphenoid
What are zonules?
Ligaments that tether the lens to the ciliary processes
Which muscle closes the upper lid?
Orbicularis oculi
Describe the course of flow of the aqueous humour
It is produced by the ciliary epithelium
Travels through the pupil
Drain via the anterior chamber angle into the venous system
What layer do extraocular muscles attachment to the eye?
The sclera
What is the lamina cribosa?
Fibres of the sclera that pass over the optic nerve in a mesh like pattern
What are the names of the ciliary arteries?
Long posterior ciliary artery
Short posterior ciliary artery
Anterior ciliary artery
Which branch of the NS innervates the ciliary muscles?
Parasympathetic
What are the layers of the cornea?
Epithelium
Bowman’s layer
Stroma
Descemet’s membrane
Endothelium
What is the function of the endothelium of the cornea?
The maintain fluid balance
What are the functions of the ciliary body?
Produce aqueous humour
Tether the lens
House the ciliary muscle
Does the fovea have rods?
Nah
Why is the cornea transparent?
Because the collagen is laid out in a very ordered manner
What is the most important role of the ciliary epithelium?
Produce aqueous humour
What is the optic nerve formed by?
Axons of ganglion cells
How can the eyelids be described?
Transition zone between conjunctiva and skin
What does the ciliary muscle do?
Allows focusing via the lens
What happens if the corneal epithelium is damaged?
It heals v. rapidly
Describe the dual blood supply of the retina?
Central retinal artery supplies the inner layer of the retina while the posterior ciliary artery supplies the outer layer of the retina
How are the cornea and sclera arranged in relation with each other?
They are continuous
When the ciliary muscles are contracted, at what distance can you focus?
Close up
Why is the sclera so hard?
The whirls of collagen provide strength
Which CN controls levator palpebrae superiosis
CNIII
Which CN innervates orbicularis oculi?
CNVII
What forms the outer layer of the eye?
Cornea
Sclera
What is the sequence of branching that leads to the central retinal artery
Internal carotid > Ophthalmic artery > Central retinal artery
What type of muscle is the ciliary muscle?
Smooth muscle
Which bones make up the medial aspect of the orbit?
Maxilla
Lacrimal
Body of the sphenoid
Ethmoid
Which bones make up the roof of the orbit?
Frontal
Lesser wing of the sphenoid
Which bones make up the floor of the orbit?
Maxilla
Zygomatic
Palantine
What is the fovea?
Specialised region for central vision
- has the highest density of cones
The structure that contains colour is called what?
The iris
Which arm of the NS innervates dilator papillae?
Sympathetic NS
Does the cornea have a direct vascular supply?
Nah, avascular
What is the function of the retina?
Light detection and translation
What is presbyopia?
The loss of accommodation (the ability to focus) with age
What makes up the second layer of the eye, aka uvea?
Iris
Ciliary body
Choroid
Which bones form the infraorbital margin of the orbit?
The maxilla medially
The zygomatic bone laterally
What occurs at the anterior chamber angle?
Meeting point of the cornea and iris
- aqueous humour drains there
