Bio Term 2 Flashcards
What are the main functions of the ciliary body
1 - to produce aqueous humour
2- to control the shape and size of lens
What are the two main sections of the ciliary body
Anterior pars plicata
Posterior pars plana
Difference between the pigmented and unpigmented epithelium in pars plicata
Pigmented epithelium contains melanin →allowing light to be absorbed in the eye → back box effect
Unipigmented epithelium responsible for producing aqueous humour
what is the inner layer of the epithelia known as
Unpigmented epithelia
What happens to the aqueous humour after being produced by the unpigmented epithelium
It gets travelled through the anterior and posterior chambers and supplies avascular lens with nutrients
Where Is the aqueous humour drained after being utilised
Canal of schlemm at filtration angle
What is the main blood supply for iris
Major iridium circle
What part of the ANS is innervated by the radial dilator muscle of the iris
Sympathetic flight or fight response causing pupils to dilate
What part of the ANS is innervated by the iris sphincter circular
Parasympathetic part causing pupils to constrict
What is the dilator muscle innervated by
Innervated by the superior cervical ganglion - spinal cord
What is the iris sphincter innervated by
By midbrain EDINGER-westphal nucleus which travels down the ciliary ganglion
Effect of severing right oculomotor nerve CNIII
This would cause a visual pathway error in the right efferent section, resulting a lack of constriction in the right pupil during pupillary light reflex
X
What are the functions of the RPE
1.) Absorbs stray light not absorbed by the photoreceptors
2.) destroys the photoreceptors via phagocytosis
3.) acts as a blood retinal barrier to control the substances which enter and exit the choriocapillaris/RPE
4.) Storage of vitamin A - pivotal visual pigment renewal
What is the interphotoreceptor matrix
Occupies Fluid filled spaces acting like glue between RPE and the photoreceptors - important in maintaining cytoskeleton organisation and preventing retinal degeneration
Retinal glial cells
Muller cells what makes up the bulk of retina - wrap itself around the ganglion cells throughout retina - similar to myelin wrapping itself worked axons
Function of Muller cells
1.) electrical insulation
2.) space fillers
3.) regeneration of cone visual pigments
4.) glycogen - nutrient hub
5.) electrophysiological function
Where does the outer retina receive its blood supply from
Nutrients from choroicapillaris
Where do inner 5 layers of retina receive its blood supply from
From the central retinal artery
Explain the blood supply of the retina from the central retinal artery
As the central retinal artery reaches the surface area of the optic disc - divides into four providing the superior, inferior nasal and temporal quadrants..
How can the retina blood vessels be seen clearly
Fluoroscein angiogram - veins will be seen with the bright fluorescein - analysing the health
Under a fundus which blood vessels appear larger - veins or arteries?
Veins are darker under the fundus because of the thinner walls - appears more red
Also deoxygenated blood tends to be more darker
