anatomy Flashcards
what are the two parts of the outer layer of the eye
sclera - muscle attachment
cornea - 2/3 of refractive power
what is the outer layer of the eye
fibrous
what is the middle layer of the eye
uvea
what are the three parts of the uvea
- iris
- ciliary body
- choroid
what is the anterior segment divided into
- anterior chamber
- posterior chamber
what does the posterior segment contain
-vitreous body
vitreous humour
what is a catact
clouding of the lens
what is in the ciliary body
- smooth muscle and blood vessels
- ciliary processes secrete aqueous
what does the aqueous circulates do
nourishes lens
what is the process of the circulation of aqueous
- ciliary body
- aqueous circulates
- aqueous then passes through pupil
- aqueous reabsorbed (into scleral venous sinus)
which vessels supplys most of the blood to the eye
the opthalmic aartery
what is an end artery
an artery with insufficient anastomoses to maintain viability of the tissue supplied if arterial occlusion occurs
which veins do most of the venous drainage of the eye
the superior and inferior opthalmic vein
what is the retina made of
- fundus
- optic disc
- macula
- fovea
function of optic disc
- point of CN II formation
- only point of entry/exit for blood vessels and axons of CN II
- blind spot
what is the fundus
-posterior area where light is focused
what is the macula
greatest density of cones
what is the fovea
- centre of macula
- area of most acute vision
what does complete interruption retinal artery branch/retinal vein mean
loss of an area of visual field corresponding to the area of ischaemia
what does a complete interruption of flow of the central artery or vein cause
monocular blindness
what is light from objects in the right visual field going to be processed by
the left primary visual cortex
what are light objects in the lower visual field going to be processed by
the upper part of the primary visual cortex
movement of vertical axis
abduction/adduction
which nerve innervates the lacrimal gland
CN VII
describe the journey of the lacrimal fluid
- produced by lacrimal gland
- wash over eye
- pushed towards medial angle
- drains through lacrimal puncta
- eventually reaches inferior meatus
what are the 4 rectus muscles
- superior rectus
- inferior rectus
- medial rectus
- lateral rectus
what are the two oblique muscles
- superior oblique
- inferior oblique
which muscle is inbetween the superior oblique and the superior rectus
the levator palpebrae superioris
where do all rectus muscles originate from
-common tendinous ring
where do all rectus muscles insert onto
sclera
where does the superior oblique muscle originate from
the sphenoid bone
where does the inferior oblique originate from
orbital plate of maxilla
where do the oblique muscles insert onto
sclera
where does the lesser palpebrae superioris originate from
lesser wing of sphenoid
where does the levator palpebrae superioris insert onto
skin and tarus of superior eyelid
innervation of the ocular muscles
lateral rectus - CN VI
superior oblique - CN IV
all others - CN III
LR6 SO4 AO3
what can raised intra-ocular pressure cause
ischaemia of the retina and glaucoma
where is aqueous reabsorbed into
scleral venous sinus at iridocorneal angle
are there any photoreceptors in the optic disc
no
movement of the transverse axis
elevation/depression
movement of the anteroposterior axis
intorsion/extorsion
what does the lateral rectus do
can only abduct the eyeball
-brings line of gaze into same plane as superior rectus and inferior rectus
which nerve innervates the lateral rectus
CN VI (abducent)
which nerve innervates the superior rectus
CN III (occulomotor)
function of the superior rectus
when in abduction, SR can only elevate
function of inferior rectus
when in abduction, IR can only depress
function of the medial rectus
can only adduct eyeball
function of inferior oblique
when in adduction, IO can only elevate
function of superior oblique
when in adduction, SO can only depress
which muscles purely elevate the eyes
superior rectus and inferior oblique
which muscles purely depress the eyes
superior oblique and inferior rectus
what are meninges
protective coverings of brain and spinal cord
what are the 3 layers of meninges
- dura mater
- arachnoid mater
- pia mater
features of the dura mater
- hard mother
- sensory supply from CN V
- encloses dural venous sinuses
features of the arachnoid mater
- spidery mother
- arachnoid granulations
what is in the subarachnoid space
circulating CSF and blood vessels
features of the pia mater
- faithful mother
- adheres to brain
label this diagram
where does a lumbar puncture have to be to access the subarachnoid space
L3/4 of L4/5 IV disc levels to obtain a sample of CSF
where does the subarachnoid space end
inferiorly at vertebral level S2
what is the circulation of CSF
- secreted by choroid plexus
- from right and left lateral ventricles
- and then into third ventricle
- then via cerebral aqueduct into the fourth ventricle
- then mainly into the subarachnoid space
- then reabsorbed via the arachnoid granulations
- into the dural venous sinuses
