Anatomy: The Eyeball Flashcards
Why will occlusion of the central artery of the retina quickly cause blindness?
It is an end artery
What is indicated by the arrow?
Optic nerve
What is indicated by the arrow?
Superior ophthalmic vein
What is the posterior segment of the eye?
Segment of eye located behind the lens; contains the vitreous body (which contains vitreous humour)
What is the fundus of the eye?
Interior (posterior) surface of the eye opposite the lens where light is focused and includes the retina, optic disc, macula, fovea, and posterior pole
What is indicated by the arrow?
Central artery and central vein of the retina
What is indicated by the arrow?
Inferior ophthalmic vein
Name the artery which supplies the internal surface of the retina
Central artery of the retina
What is indicated by the arrow?
Iris
What is indicated by the arrow?
Posterior segment
What is indicated by the arrow?
Lower eyelid (lined by conjunctiva)
What is indicated by the arrow?
Posterior chamber
What is indicated by the arrow?
Lacrimal lake
Describe the structure of the ciliary body
Comprised of two parts, the ciliary muscle and ciliary processes
The ciliary muscle consists of a collection of smooth muscles fibres which are attached to the lens of the eye by the ciliary processes
Describe the circulation of aqueous humor in the anterior segment of the eye
- Secretion of aqueous by the ciliary processes of the ciliary body
- Aqueous circulates within posterior chamber to nourish lens
- Aqueous then passes through pupil into anterior chamber to nourish cornea
- Aqueous reabsorbed into scleral venous sinus (Canal of Schlemm) at iridocorneal angle
Name the light detecting component of the eye
Retina
What is the optic disc?
Formed by axons of ganglion cells that leave the eye to form the optic nerve (CN II formation)
What is indicated by the arrow?
Branches of retinal vessels (arterioles and venules)
The _______ provides attachment for the extraocular muscles
Sclera
What is the function of the ciliary body?
Adapts the shape of the lens, anchors the lens and produces aqueous humor
How is it possible that retrograde infection from the nasal area can to spread to the brain, forming the so-called ‘danger triangle’?
Due to the venous communication (via the opthalmic veins) between the facial vein and the cavernous sinus
What is the fovea?
Depression 1.5 mm diameter at the centre of the macula, responsible for high acuity vision
What is indicated by the arrow?
Choroid
In fundoscopy, what does the complete interruption of retinal artery branch/retinal vein indicate?
Loss of an area of visual field corresponding to the area of ischaemia
The retinal veins and retinal arteries lie ________ to the retina
Anterior
What is the iris?
Pigmented membrane with a central opening (the pupil) which adjusts its size in response to light
What is indicated by the arrow?
Iris (covered by cornea)
Light from objects in the _____ visual field strike the nasal retina of the left eye and the temporal retina of the right eye, and vice versa
Left
Why are the layers of the retina described as ‘inverted’?
The light sensing cells are in back of the retina, so that light has to pass through layers of neurons and capillaries before it reaches the rods and cones
What is indicated by the colour green?
Cornea