Anatomy Flashcards
What is the corneal epithelium?
How many layers?
What are these layers?
Stratified, squamous, non keratinised and non secretory
5-7 layers
Basal layer of columnar cells (tightly adhered to the basement membrane)
2-3 layers of interdigitating wing cells
3-4 layers of flattened nucleated squamous cells (squames)
How are the superficial layers of the epithelium joined?
Wing cells?
Basal cells
Desmosomes- tight junctions
Desmosomes + Gap junctions
Desmosomes + gap junctions + Hemidesmosomes
What is the lamina Lucida and the lamina densa?
The basement membrane, between the epithelial cells and stroma
What % of the cornea does the stroma make up
90%
What produces the lamellar stroma?
What do they produce?
Stromal fibroblasts (keratocytes)
Proteases
What is the main collagen type of the cornea?
Type 1
Overproduction of what causes corneal melting?
Proteases, inflammatory cells and bacteria
What secretes the descemets membrane?
Corneal endothelium
How many cell layers is the endothelium?
What shaped cells?
How are endothelial cells connected?
Single cell layer
Low cuboidal
Tight junctions and gap junctions
What is the process for stromal hydration?
Na K ATPase
What provides corneal epithelial nutrition?
Tear film
Limbal blood vessels
Aqueous humour
When does stromal healing occur?
Once re epithelialisation has occurred
Is the sphincter muscle in the iris supplied by the sympathetic or parasympathetic NS?
Which nerve?
What does it do to the pupil- constricts/ dilated?
Parasympathetic
Oculomotor nerve III
Constricts the pupil
Is the dilator muscle in the iris supplied by the sympathetic or parasympathetic NS?
Sympathetic
What is the function of the ciliary body?
Secreting aqueous
Nourishing the lens
Muscle for accommodation of the lens
What part of the ciliary body secretes the aqueous humour?
Non pigmented epithelium
Where does the lens get its nutrients from?
Aqueous humour
Where does conventional drainage occur for aqueous?
Iridocorneal angle
What is ‘unconventional drainage’ for aqueous outflow?
Via the uveoscleral outflow
Through the ciliary body and choroid
Does IOP increase or decrease with age?
Increase
What is the vitreous made up of?
99% water
Collagen
Hyaluronic acid
Few cells (hyalocytes)
What are the 10 layers of the retina?
What is the retinal pigment epithelium continuous with? LAYER 1
Where are the cells not pigmented?
Outer pigmented epithelium of the ciliary body
Tapetum lucidum
What does the visual cell layer have in the retina? LAYER 2
Function of these cells?
PHOTORECEPTORS
Light sensitive cells;
Rods (95%)
Cones (5%) - in the area centralis lateral to the optic disc
Rods - function in dim/ reduced light, detection of shapes/ motion
Cones - function in bright light, sharp visual acuity and colour sensation
Photopigment produce chemical energy when exposed to light, converted in to electrical energy.
What is in the outer nuclear layer of the retina? LAYER 4
Photoreceptor cell bodies and nuclei
What is in the outer plexiform layer of the retina? LAYER 5
Branching terminals of the rod and come cell axons
What is in the inner nuclear layer in the retina? LAYER 6
Cell bodies of the horizontal cells, bipolar cells, amacrine cells and Muller cells
What is in the inner plexiform layer in the retina? LAYER 7
Cell processes of inner nuclear layer synapse with ganglion cells
What cells are in the nerve fibre layer in the retina? LAYER 9
Ganglion cells (unmyelinated)
Which layers do the retinal vessels lie?
Nerve fibre layer 9
Ganglion cell layer 8
Inner plexiform layer 7
What is a holangiotic fundus?
Species?
Retina is nourished by arteries and veins on its surface
Cats and dogs
What is an anangiotic fundus?
Species?
Vasculature is restricted to the pecten
Avian
What is a merangiotic fundus?
Species?
Horizontal band of vessels (medially a laterally)
Rabbit
Are photoreceptors in a depolarised state in light or dark?
Dark
Are photoreceptors in a hyperpolarised state in light or dark?
Light
Which dogs can have an absence of a tapetum?
Merle collies
In dogs, long coat length correlates with what type of transition between the tapetum and non tapetum?
Gradual or abrupt?
Gradual
In dogs, short coat length correlates with what type of transition between the tapetum and non tapetum?
Gradual or abrupt?
Abrupt
Is the optic disc in the dog myelinated or unmyelinated?
Myelinated
Is the optic disc in the cat myelinated or unmyelinated?
Unmyelinated
What is a, b and c in an ERG?
A wave photoreceptors
B wave layers of the retina
C wave RPE
Is an ERG a cone or rod dominated response?
Rod
Which organ is an essential component of ACAID? (Anterior chamber associated immune deviation)
Spleen
What is the only lymphatic drainage of the eye?
Conjunctiva associated lymphoid tissue
